Emerson SiteLink-4 Network Router User Manual

MODEL 4809
owners manual
Introduction
3 Before You
Proceed
4 Safety
Precautions
5 Tools, Supplies
and Required
Equipment
6 Anatomy of
Your Nitro 4-Tec
7 Quick Start:
Getting Up
to Speed
8 Decorating and
Installing your
Nitro 4-Tec Body
9 The Traxxas
TQ Radio System
17 The TRX 3.3
Racing Engine
32 Driving Your
Nitro 4-Tec
33 Adjusting Your
Nitro 4-Tec
36 Maintaining
and Storing
Your Nitro 4-Tec
38 Troubleshooting
40 Index
2 • Nitro 4-Tec 3.3
Thank you for purchasing the Traxxas Nitro 4-Tec 3.3™ all-wheel-drive
nitro supercar. The Nitro 4-Tec 3.3 was designed to deliver extreme
power for expert drivers. It is the most powerful Ready-To-Race® allwheel-drive nitro supercar ever conceived. The incredible TRX 3.3
Racing Engine is bigger, faster, and puts out a whopping 60% more
peak horsepower compared to the legendary, award-winning TRX 2.5.
Relentless horsepower and the lightweight Nitro 4-Tec 3.3 platform
combine for a driving experience that is like no other. The explosive
acceleration and extreme top speed are intended to test the reflexes
of only the most skilled and experienced drivers. The broad linear
power output of TRX 3.3 Racing Engine delivers responsive,
pavement-burning power at almost any speed.
Nitro 4-Tec 3.3 is made to be a complete package that starts with the
highest level of engineering; a professionally produced DVD to
acquaint you with the starting, racing, and maintenance procedures;
and is equipped stock with the most powerful Ready-To-Race®
smallblock engine available. We want you to feel confident that you
own the best performing car in the market and that it is backed by a
team of professionals who aim to provide the highest level of factory
support possible. Nitro 4-Tec 3.3 is about experiencing total
performance and satisfaction, not just with your car, but also with the
company that stands behind it.
Thank you again for going with Traxxas. We work hard every day to
assure you the highest level of customer satisfaction possible. We
truly want you to enjoy your new Nitro 4-Tec 3.3!
Traxxas Support
Traxxas support is with you every step of the way.
Refer to the next page to find out how to contact
us and what your support options are.
Quick Start
This manual is designed with a Quick Start path
that covers only the necessary procedures to get your model
up and running in the shortest time possible. If you are an
experienced R/C enthusiast you will find it helpful and fast.
Be sure and read through the rest of the manual to learn
about important safety, maintenance, and adjustment
procedures. Turn to page 7 to begin.
We know you’re excited about getting your new Nitro 4-Tec 3.3 on
the road, but it’s very important that you take some time to read
through the Owners Manual. This manual contains all the necessary
set-up, break-in, tuning, and operating procedures that allow you to
unlock the incredible performance and adjustment potential that
Traxxas engineers designed into Nitro 4-Tec 3.3. Even if you are an
experienced R/C enthusiast, it’s important to read and follow the
procedures in this manual. Nitro 4-Tec 3.3 contains new
technologies in the engine, suspension, and transmission
operation that you may not be familiar with. Pay particular
attention to the fuel and break-in requirements for the engine.
The advanced design of the TRX 3.3 Racing Engine has a special
break-in procedure that has been developed and proven to
produce the best-performing engine possible. Using traditional
or old-fashioned procedures could reduce engine performance
and longevity.
Before You Proceed
Carefully read and follow all instructions in this and any accompanying
materials to prevent serious damage to your Nitro 4-Tec 3.3. Failure to
follow these instructions will be considered abuse and/or neglect.
WARNING! NOT A TOY! Read carefully! This product is capable of
extreme speed and acceleration! It is intended for expert drivers only.
Experience with nitro-powered radio controlled models is required.
The driver must exercise all caution and accept full responsibility for
their own safety, and the safety of others nearby. Full-speed operation
requires a large, smooth running area free of obstacles and closed off
to pedestrian and automobile traffic. This product is not designed for
children under 16. Responsible adult supervision is required during
operation and maintenance. For outdoor use only.
Nitro 4-Tec 3.3 is very fast and carries our highest skill level rating of 5
(Expert. For experienced drivers only!). Prior experience with R/C models
is required. Nitro 4-Tec 3.3 is a high-performance model which is NOT
intended for use on public roads or in congested areas where its
operation may conflict with or disrupt pedestrian or vehicular traffic. Read
all enclosed information before operating. Fully illustrated, step-by-step
instructions describe adjustment and required maintenance procedures.
Nitro 4-Tec 3.3 should not be operated in a crowd, indoors or without
adequate space and ventilation. The vehicle is fully assembled, ready-torun, and requires the following items for operation: 12 AA alkaline
batteries, model car fuel, a 7.2 volt rechargeable battery pack, and a
charger. These items are available from your hobby dealer. In an effort to
continually upgrade our products, Traxxas reserves the right to make
improvements and modifications to this model, which may not be
reflected in the photographs and specifications printed in this manual.
Before running your Nitro 4-Tec 3.3, look over this entire manual and
examine the car carefully. If for some reason you decide Nitro 4-Tec 3.3 is
not what you wanted, then do not continue any further. Your hobby
dealer absolutely cannot accept a Nitro 4-Tec 3.3 for return or exchange
after it has been run.
Warnings, helpful hints, & cross-references
Throughout this manual, you’ll notice warnings and helpful hints
identified by the icons below. Be sure to read them!
An important warning about personal safety or avoiding
damage to your Nitro 4-Tec 3.3 and related components.
Special advice from Traxxas to make things easier and more fun.
Traxxas
1100 Klein Road
Plano, Texas 75074
Phone: 972-265-8000
Toll-free 1-888-TRAXXAS
Traxxas U.K.
P.O. Box 1128
Winterbourne, Bristol BS36-2SH
England
Phone: 44-117-956-1002
Refers you to a page with a related topic.
Internet
www.Traxxas.com
E-mail: support@Traxxas.com
Support
If you have any questions about your Nitro 4-Tec 3.3 or its operation,
call the Traxxas Technical Support line toll-free at:
1-888-TRAXXAS (1-888-872-9927)*
Technical support is available Monday through Friday from 8:30am
to 9:00pm central time. Technical assistance is also available at
www.Traxxas.com. You may also e-mail customer support with your
question at support@Traxxas.com. Join thousands of registered
members in our online community at Traxxas.com.
Traxxas offers a full-service, on-site repair facility to handle any of
your Traxxas service needs. Maintenance and replacement parts
may be purchased directly from Traxxas by phone or online at
www.BuyTraxxas.com. You can save time, along with shipping and
handling costs, by purchasing replacement parts from your local dealer.
Entire contents ©2006 Traxxas.
Traxxas, Nitro 4-Tec, TRX 3.3
Racing Engine, TQ, Top Fuel,
EZ-Start, Ready-To-Race, ReadyTo-Win, and ProGraphix are
trademarks or registered
trademarks of Traxxas. Other
brand names and marks are the
property of their respective
holders and are used only for
purposes of identification. No
part of this manual may be
reproduced or distributed in
print or electronic media without
the express written permission
of Traxxas.
Do not hesitate to contact us with any of your product support needs.
We want you to be thoroughly satisfied with your new Nitro 4-Tec 3.3!
*Toll-free support is available to U.S. residents only.
Nitro 4-Tec 3.3 • 3
Safety Precautions
All instructions and
precautions outlined in
this manual should be
strictly followed to ensure
safe operation of your
Nitro 4-Tec 3.3.
Nitro 4-Tec 3.3 is not intended
for use by children under 16
years of age without the
supervision of a responsible
and knowledgeable adult.
Not a Toy! For Expert Drivers
Only! This product is capable
of extreme speed and
acceleration! It carries our
highest skill level rating (5)
and is intended for expert
drivers only. Experience with
nitro-powered radio controlled
models is required. The driver
must exercise all caution and
accept full responsibility for
their own safety, and the
safety of others nearby.
Full-speed operation requires
a large, smooth running area
free of obstacles and closed
off to pedestrian and
automobile traffic.
All of us at Traxxas want you to safely enjoy your new Nitro 4-Tec 3.3.
Operate your Nitro 4-Tec sensibly and with care, and it will be exciting,
safe, and fun for you and those around you. Failure to operate your Nitro
4-Tec in a safe and responsible manner may result in property damage
and serious injury. The precautions outlined in this manual should be
strictly followed to help ensure safe operation. You alone must see that
the instructions are followed and the precautions are adhered to.
Important Points to Remember
This product is capable of extreme speed and acceleration! It is
intended for expert drivers only. Experience with nitro-powered
radio controlled models is required. The driver must exercise all
caution and accept full responsibility for their own safety, and the
safety of others nearby. Full-speed operation requires a large,
smooth running area free of obstacles and closed off to pedestrian
and automobile traffic.
Model engine fuel is dangerous and highly poisonous. Always follow
all directions and precautions printed on the fuel container. Model
engine fuel is poisonous to humans and animals. Drinking the fuel can
cause blindness and death. Handle with care and respect.
Model engine fuel, especially when in a fuel dispensing bottle, may
look like a cool drink to a child. Keep all fuel out of the reach of
children at all times. Do not place fuel containers on the ground
where children can get to them while you are driving.
Model engine fuel is flammable. Never allow smoking, sparks, heat or
flame in the presence of fuel or fuel vapors.
The engine, brakes, and exhaust system may become extremely hot
during use. Be careful not to touch the parts, especially when
refueling or stopping the engine.
For outdoor use only. Prolonged exposure to the engine exhaust
can be harmful. Avoid breathing the engine exhaust. Always run
your Nitro 4-Tec outdoors, in a well-ventilated area. Never run the
engine indoors.
4 • Nitro 4-Tec 3.3
Do not operate your Nitro 4-Tec at night, or anytime your line of sight to
the model may be obstructed or impaired in any way.
Never operate your Nitro 4-Tec in crowds of people or busy pedestrian
areas. Nitro 4-Tec is very fast and could cause injury to those unaware
of its presence.
Because Nitro 4-Tec is controlled by radio, it is subject to radio
interference from many sources beyond your control. Since radio
interference can cause momentary loss of control, always allow a
safety margin in all directions around your model to prevent collisions.
The engine can be loud. If the noise makes you uncomfortable, wear
ear protection. Be considerate of your neighbors by not running your
model early in the morning or late in the evening.
Most importantly, use good common sense at all times.
Tools, Supplies, and Required Equipment
Your Nitro 4-Tec 3.3 comes with a set of specialty metric tools. You’ll need to purchase other items, available from your hobby dealer, to operate and maintain your model.
Supplied Tools and Equipment
Turnbuckle wrenches
1.5mm “L” hex wrench
For more information on
radio system batteries, see
Use the Right Batteries on
page 11.
2.0mm “L” hex wrench
Required Tools and Equipment
Glow plug and
wheel nut wrench
4-way wrench
U-joint wrench
2.5mm “L” hex wrench
Antenna nut wrench
(sold separately)
Foam air filter oil and
extra oiled air filter element
(see page 22)
10% quart - #5010
20% quart - #5020
33% quart - #5030
10% gallon - #5060
20% gallon - #5070
33% gallon - #5080
Traxxas Top Fuel™
see page21
Fuel dispensing bottle
Part #5001
After-run oil to protect
the engine from corrosion
Accessory Equipment
TRX Power Charger
Traxxas part #3030X
NiCad or NiMH battery charger
Traxxas part #3030X shown
NiCad or NiMH
7.2V battery pack
12 AA alkaline batteries
Hobby knife
Philips screwdriver
A peak-detecting charger,
such as the TRX Power
Charger (part #3030X), is
recommended for best
performance and longest
battery life. For more
information, see Use the
Right Charger on page 25.
Recommended Equipment
These items are not
required for the operation
of your model, but are a
good idea to include in any
R/C toolbox:
• Safety glasses
• Thin, hobby-quality
cyanoacrylate instant tire
glue (CA glue)
• Side cutters or needle
nose pliers
• Metric hex driver set
Small flat-blade screwdriver
for tuning (1/8 inch blade)
(sold separately)
RX battery power pack
Traxxas part #3037
RX Wiring Harness
Traxxas part #3034
DC car adapter for TRX Power Charger
Traxxas part #3032
Nitro 4-Tec 3.3 • 5
Anatomy of Your Nitro 4-Tec 3.3
Chassis (lower)
TRX 3.3 Racing Engine
see pg. 18 for details
Racing Tires
Pressure
Line
Antenna
Mount
Servo
Saver
Receiver
Header
EZ-Start
Motor
Crystal
Access
Pipe
Steering
Bellcrank
Pipe
Hanger
Tie Rod
(Turnbuckle)
Front Camber Link
(Turnbuckle)
Front Bumper
Plate
Shock
Tower
Body
Mount
EZ-Start
Plug
Rear
Differential
Air
Filter
Fuel Line
Center
Drive Belt
Rear
Suspension Arm
Two-Speed Transmission
6 • Nitro 4-Tec 3.3
Throttle/Brake Servo
Fuel Tank
Drive Belt
Pulley
Bearing
Block
Battery Holder
Fuel Tank Lid
Body
Mount
Front
Drive Belt
Shock
(Oil Damper)
On/Off
Switch
Front
Differential
Quick Start: Getting up to Speed
The following guide is an overview of the procedures for getting your Nitro 4-Tec 3.3 running, from opening the box to breaking in and tuning
your engine. Refer to the pages indicated for details on each step. Look for the Quick Start logo on the bottom corners of Quick Start pages.
1. Read the safety precautions on page 4
For your own safety, understand where carelessness and misuse
could lead to personal injury.
10. Check servo operation • See page 16
Make sure the throttle, shifting, and steering servos are
working correctly.
2. Charge the EZ-Start battery pack • See page 25
The EZ-Start requires a fully charged 7.2-volt battery
pack (sold separately).
11. Range test the radio system • See page 16
Follow this procedure to make sure your radio system works properly
at a distance and that there is no interference from outside sources.
3. Install the antenna • See page 13.
Install the antenna mast in Nitro 4-Tec.
12. Fill the fuel tank • See page 22
Use your fuel-dispensing bottle to fill the tank.
4. Decal and Install the body • See page 8
You will need to use the body during break in, so it's best to apply
any additional decals before you use the body.
13. Connect the EZ-Start to the model • See page 26
Learn the proper way to use the EZ-Start electric starting system
5. Install the body mounts • See page 8
Install the body mounts and foam bumper.
14. Start the engine • See page 27
Learn to use the correct starting procedure for your TRX 3.3.
6. Install batteries in the transmitter • See page 11
Nitro 4-Tec requires 8 AA alkaline or rechargeable batteries
for the transmitter.
15. Break-in your engine • See page 27
Follow the break-in instructions exactly to ensure the
best-performing, longest-lasting engine.
7. Install batteries in the model • See page 12
The Nitro 4-Tec requires 4AA alkaline or rechargeable
batteries for the receiver.
16. Tune your engine • See page 29
Learn how to set the fuel mixture needles for optimum
engine performance.
8. Install the EZ-Start battery • See page 25
Install and connect a charged 7.2-volt battery pack
in the EZ-Start controller.
17. Drive your Nitro 4-Tec • See page 32
Driving tips and adjustments for your Nitro 4-Tec.
9. Turn on the radio system • See page 15
Make a habit of turning the transmitter on first, and off last.
18. Maintaining your Car • See pages 36-37
Follow these critical steps to maintain the performance of your
Nitro 4-Tec and keep it in excellent running condition.
The Quick Start Guide is
not intended to replace
the full operating
instructions available in
this manual. Please read
this entire manual for
complete instructions
on the proper use and
maintenance of
your Nitro 4-Tec.
Look for the Quick Start
logo at the bottom of
Quick Start pages.
Nitro 4-Tec 3.3 • 7
Decorating Installing your Nitro 4-Tec 3.3 Body
Applying The Decals
Installing
The main decals have already been
applied to your Nitro 4-Tec. The extra
decals provided are die-cut for easy
removal. Use a hobby knife to lift the
corner of a decal and remove it from
the backing.
The body mount parts are located
in a separate bag with your
instructions. The front body mount
posts attach to the front bumper
with 3x10mm countersunk cap
screws. Slide the foam bumper
over the front mounts, as shown in
the drawing. The excess length of
the mounts should be trimmed off
after the body is installed.
Carefully position the decal over the
desired location and press one side on
the body. Pull the decal tight and use
a finger to gradually smooth out any
air bubbles as you apply the decal.
Foam
Bumper
The Body Mounts
Installing Front Body Mounts
Foam
Bumper
The rear body mounts attach as
shown in the drawing.
Look at the photos on the box for
typical decal placement.
Installing Rear Body Mounts
3x14mm
buttonhead
cap screws
3x10mm countersunk
cap screws
3x10mm countersunk
cap screws
8 • Nitro 4-Tec 3.3
The Traxxas TQ Radio System
Your Nitro 4-Tec (model 4809) is equipped with the TQ Radio System. The TQ is a 2-channel system that provides high-power output up
to a quarter mile and control for two servos. The Nitro 4-Tec makes use of two channels for throttle/brake and steering.
TQ Transmitter
Antenna
Nitro 4-Tec 3.3 Wiring Diagram
4-Cell Battery
Holder
Throttle Neutral Adjust
Steering Wheel
Throttle Trim
Steering Trim
On/Off
Switch
Antenna
Steering
Servo
Throttle
Servo
Throttle
Trigger
CH.2
CH.1
Receiver
Servo Reversing
Switch
Power Switch
Battery Compartment
Battery
Channel 1
Channel 2
Not Used (Channel 3)
Power Indicator
Nitro 4-Tec 3.3 • 9
The Traxxas TQ Radio System
Radio System Terminology
Learn terms related to the
TRX 3.3 Racing Engine
beginning on page 19.
Please take a moment to familiarize yourself with these radio-system
terms. They will be used throughout this manual.
Channel - The 27 MHz frequency band is divided into 6 channels so that
up to six models can be operated simultaneously. Each channel is
referred to by its flag color and channel number, as shown below.
1
Frequency
Band
26.995
Flag
Color
Brown
Traxxas
Part No.
2031
2
27.045
Red
2032
3
27.095
Orange
2033
4
27.145
Yellow
2034
5
27.195
Green
2035
6
27.255
Blue
2036
Channel
Clearing your frequency - A routine, verbal check to make sure
nobody else in your area is operating on the same channel. Always
clear your frequency by calling out your channel number before
operating your model. Wait or move to another area if your channel
is already being used.
Crystal (X-tal) - The plug-in device that determines which channel the
radio system will operate on. For each channel, there are two crystals,
one for the receiver and one for the transmitter. Of those two crystals,
the one marked “RX” with the lower number (.455 MHz lower) must be
inserted into the receiver.
Frequency band - The radio frequency used by the transmitter to send
signals to your Nitro 4-Tec. All Traxxas RTR models operate on a 27
MHz frequency band.
mAh – Abbreviation for milliamp hour. Measure of the capacity of the
battery pack. The higher the number, the longer the battery will last
between recharges.
Neutral position - The standing position that the servos seek when the
transmitter controls are at the neutral setting.
10 • Nitro 4-Tec 3.3
NiCad - Abbreviation for nickel-cadmium. The original rechargeable
hobby pack, NiCad batteries have very high current handling, high
capacity, and can last up to 1000 charging cycles. Good charging
procedures are required to reduce the possibility of developing a
“memory” effect and shortened run times.
NiMH - Abbreviation for nickel-metal hydride. Rechargeable NiMH
batteries offer high current handling, and much greater resistance
to the “memory” effect. NiMH batteries generally allow higher
capacity than NiCad batteries. They can last up to 500 charge
cycles. A peak charger designed for NiMH batteries is required
for optimal performance.
Receiver - The radio unit inside your Nitro 4-Tec that receives signals
from the transmitter and relays them to the servos.
Servos - Small motor units in your Nitro 4-Tec that operate the throttle
and steering mechanisms.
Two-channel radio system - The TQ radio system, consisting of the
receiver, the transmitter, and the servos. The system uses two
channels: one to operate the throttle and one to operate the steering.
Transmitter - The hand-held radio unit that sends throttle and steering
instructions to your Nitro 4-Tec.
Trim - The fine-tuning adjustment of the neutral position of the servos,
made by turning the throttle and steering trim knobs on the face of
the transmitter.
The Traxxas TQ Radio System
Installing Transmitter Batteries
Your TQ transmitter uses 8 AA batteries. The battery compartment is
located in the base of the transmitter.
Use the Right Batteries
CH.1
CH.2
4. Turn on the transmitter and check the power indicator for a
solid red light.
If the power indicator light flashes, then the transmitter batteries are
weak, discharged or possibly installed incorrectly. Replace with new or
freshly charged batteries. The power indicator light does not indicate
the charge level of the RX Power Pack installed in the model.
1. Remove the battery compartment door by pressing the tab and
lifting the door up.
2. Install the batteries in the correct orientation as indicated in the
battery compartment.
3. Reinstall the battery door and snap it closed.
Your transmitter uses AA
batteries. Use new alkaline
batteries, or rechargeable
batteries such as NiCad or
NiMH (Nickel Metal Hydride)
batteries in your
transmitter. Make sure
rechargeable batteries are
fully charged according to
the manufacturer’s
instructions.
If you use rechargeable
batteries in your
transmitter, be aware
that when they begin
to lose their charge, they
lose power much more
quickly than regular alkaline
batteries.
Caution: Discontinue
running your Nitro 4-Tec at
the first sign of weak
batteries (flashing red light)
to avoid losing control.
If the power indicator
doesn’t light red, check the
polarity of the batteries.
Check rechargeable
batteries for a full charge.
Nitro 4-Tec 3.3 • 11
The Traxxas TQ Radio System
Installing the Receiver Batteries
If you use rechargeable
batteries in your receiver,
be aware that when they
begin to lose their charge,
they lose power much more
quickly than regular
alkaline batteries. Signs of
weak receiver batteries
include sluggish steering
response and shortened
radio range. Caution:
Discontinue running your
Nitro 4-Tec at the first sign
of weak batteries to avoid
losing control.
The radio receiver in your Nitro 4-Tec uses 4 AA batteries. The receiver
battery holder is located underneath the top plate, just to the right of
the fuel tank.
1. Press the tab on the reusable zip tie to release the
battery holder.
4. Install the battery holder into the car
and secure it to the top plate with the
reusable zip-tie. Make sure the battery
holder is secure in the model and will not
come loose. If the tie wrap is loose, it will
interfere with the middle drive belt.
Traxxas TRX Power System (optional)
If the radio system doesn’t
appear to work when the
transmitter and receiver
switches are turned on,
check for correct battery
installation.
2. Remove the battery holder and
install 4 AA alkaline batteries.
Make careful note of the battery
polarity by comparing against the
diagrams in the battery holder.
3. Stretch a rubber balloon over the
battery holder to prevent fuel
contamination.
The optional Traxxas TRX Power System can be
purchased separately to power the radio system
in the Nitro 4-Tec 3.3. Benefits include the
economy of a rechargeable 5-cell nickel metal
hydride (NiMH) battery pack that replaces AA
alkaline batteries, and increased voltage for
dramatically improved servo performance. The
TRX Power Charger (Part #3030X) is a peak-detecting unit that will
charge the RX Power Pack (Part #3036 flat pack or #3037 hump pack) in
about one hour. The peak detection circuitry automatically shuts off the
charger when the maximum charge has been achieved. The TRX Power
Charger also includes a 7.2V adapter for charging 7.2V EZ-Start batteries.
The TRX Power Charger can operate on either AC or DC power. A special
wiring harness for Nitro 4-Tec (Traxxas part #3034) that includes a handy
external charging jack is required.
The optional DC car adapter (Part #3032) features a
tangle-free, extra long wire and integrated fuse. The
long charging cord allows the model to remain outside
the car while charging. Caution! Never charge batteries
in an enclosed car interior or while driving. Never leave
charging batteries unattended. Monitor them closely.
Traxxas' integrated TRX Power System is the easiest way to add the
power and economy of rechargeable batteries to your Nitro 4-Tec 3.3.
Consult your hobby dealer for purchasing information.
12 • Nitro 4-Tec 3.3
The Traxxas TQ Radio System
Setting up the Antenna
You must install the antenna mast (tube) before you operate your
Nitro 4-Tec. You’ll find the plastic antenna tube and tip in the bag
with your manuals and documentation.
Antenna Tip
Antenna Sleeve
1. Locate the black antenna wire that exits the receiver cover. The
receiver cover is located between the fuel tank and the tuned
pipe. The antenna wire exits the cover towards the front.
Don’t shorten the length
of the antenna wire. Its
length is tuned to the
frequency band; cutting it
could severely shorten the
radio system’s range.
2. Pull the wire straight with your fingers and then insert the end of
the wire into one end of the antenna tube (the antenna tube, tip,
crimp nut and sleeve are located in the documents bag). Push the
wire all the way through the antenna tube.
3. Carefully position the wire so it exits through the slot in
the molded antenna post and insert the base of the tube into
the antenna post.
Antenna Tube
4. Slide the crimp nut over the antenna tube and screw it onto the
antenna post. Use the supplied tool to tighten the crimp nut on
the post just until the antenna tube is securely in place. Do not
over tighten or crush the antenna wire against the top plate.
5. Fold the top of the antenna wire over the top of the antenna
tube. Slide the antenna sleeve over the tube to retain the
antenna wire. Now slide the antenna tip onto the top of the
antenna tube. Never
cut or shorten the antenna wire.
Spray a little window
cleaner on the antenna
wire to make it easier
to push through the
antenna tube.
Don’t push the
transmitter antenna down
from the top. Pull it down
from the bottom, one
segment at a time, to
prevent binding and
kinking the antenna mast.
Antenna Wrench
6. On the transmitter, always fully extend the telescoping antenna
when running your 4-Tec. Make a habit of holding the transmitter
so the antenna points straight up.
Antenna Crimp Nut
Antenna Post
Nitro 4-Tec 3.3 • 13
The Traxxas TQ Radio System
There are two settings available:
TQ Radio System Controls
RN RIGHT
TU
N LEFT
TUR
Steering
50/50: Allows equal travel for both
acceleration and braking.
70/30: Allows more throttle travel
(70%) and less brake travel (30%).
50/50 is the required setting for Nitro 4-Tec
with the TRX 3.3 Racing Engine.
Electronic Throttle Trim
Brake
The electronic throttle trim located on the face of the transmitter adjusts
the neutral (center) point of the throttle servo when the servo is at rest.
This control has been preset for you at the factory. If necessary, adjust
the control so that the carburetor is at idle, and the brakes are not
applied (the model will roll freely). Do not use the throttle trim to raise
or lower the engine idle speed. Make the idle speed adjustment on the
carburetor.
Electronic Steering Trim
Neutral
The electronic steering trim located on the face of the transmitter
adjusts the neutral (center) point of the steering servos when the servos
are at rest. Adjust this control to make the model drive straight with no
steering input at the wheel.
Servo Reversing Switches
CH.1
CH.2
Accelerate
The servo reversing switches are located on the front of the transmitter,
next to the on/off switch. Moving a switch reverses the direction of the
corresponding servo. Each switch corresponds to a channel, as shown
below. For example, if you turn the steering wheel to the right and your
front wheels turn left, you would move the channel 1 switch to correct
the servo direction. It may be
necessary to adjust the
corresponding trim control after
moving a switch. The default
position for the servo reversing
switches is shown.
CH.1
TQ Radio System Adjustments
In addition to the electronic throttle and steering trim controls, your radio
system features throttle neutral adjustment and servo reversing switches.
CH.1
Throttle Neutral Adjustment
The throttle neutral adjustment is located on the transmitter face and
controls the forward/reverse travel of the throttle trigger. Change the
adjustment by pressing the button and sliding it to the desired position.
14 • Nitro 4-Tec 3.3
CH.2
TQ Channel to Servo Chart
Channel
1
2
Servo
Steering
Throttle & braking
Default Setting
Left
Right
CH.2
The Traxxas TQ Radio System
Always have the transmitter and receiver turned on before you start
the engine. Never turn the radio system off while the engine is
running. The on/off switch in the model only turns the receiver on
and off. It does not turn off the engine.
TQ Radio System Rules
Each time you prepare to run your Nitro 4-Tec,
you must clear your frequency to be sure no
one else in the area is using the same channel
as you.
Channel 1
Brown
Channel 2
Red
Always use new or freshly charged batteries for the radio system.
Weak batteries will limit the range of the radio signal between the
receiver and the transmitter. Loss of the radio signal can cause you to
lose control of your Nitro 4-Tec.
Channel 3
Orange
There are six possible channels, numbered 1
through 6. Each is represented by a color. Look
at the crystal plugged into the back of your
transmitter to determine which channel your
car is assigned to.
Channel 4
Yellow
Remember, always turn the
TQ transmitter on first and
off last to avoid damage to
your Nitro 4-Tec. Never turn
the radio off while the
engine is running.
Channel 5
Green
Channel 6
Blue
Always turn your TQ transmitter on first and off last. This procedure
will help to prevent your Nitro 4-Tec from receiving stray signals from
another transmitter, or other source, and running out of control.
CH.1
CH.2
1
2
3
Always turn your transmitter on first.
Always turn your receiver on second.
Then start your engine.
Nitro 4-Tec 3.3 • 15
The Traxxas TQ Radio System
Using the TQ Radio System
When the engine is running,
do not use the throttle trim
on the transmitter to adjust
the engine idle speed.
Always use the idle speed
adjustment screw (see page
18) on the carburetor.
Don’t attempt to operate
your Nitro 4-Tec 3.3 if
there are any problems
with your radio system
or radio interference at
your location.
The TQ Radio System was pre-adjusted at the factory. The adjustment
should be checked before running the model, in case of movement
during shipping. Here’s how:
7. Once adjustments are made, turn off the receiver on your Nitro 4-Tec,
followed by the hand-held transmitter.
Throttle
1. Fully extend the chrome antenna mast on the transmitter and turn
the switch on. The red indicator light on the transmitter should be
solid red (not flashing).
2. Turn on the receiver switch in the model. The switch is located on the
rear shock tower.
3. Position the Nitro 4-Tec so that its front wheels are off the ground.
4. Turn the steering wheel on the transmitter back and forth and check
for rapid operation of the steering servo. Also, check that the steering
mechanism is not loose or binding. If the steering operates slowly,
check for weak receiver batteries.
5. When looking down at model, the front wheels should be pointing
straight ahead. If the wheels are turned slightly to the left or right,
slowly adjust the steering trim control on the transmitter until they
are pointing straight ahead.
Brake
Throttle/Brake
Servo
Steering
Servo
Nitro 4-Tec
Servo Operation
Range-Testing the TQ Radio System
Before each running session with your Nitro 4-Tec, you should range-test
your radio system to ensure that it operates properly.
1. Turn on the radio system and check its operation as described in the
previous section (Using the TQ Radio System).
2. Have a friend hold the model with the engine off.
3. Make sure your transmitter antenna is fully extended, and then walk
away from the model with the transmitter until you reach the farthest
distance you plan to operate the model.
4. Operate the controls on the transmitter once again to be sure that
the model responds correctly.
0°
0°
6. Operate the throttle trigger on the transmitter and check for rapid
operation of the throttle servo. When the throttle-1°
trigger is pulled
TO
back, the carburetor should open. When the throttle trigger
-2° is
pushed all the way forward, the brake should lock.
16 • Nitro 4-Tec 3.3
5. Do not attempt to operate the model if there is any problem with the
radio system or any external interference with your radio signal at
your location.
The TRX 3.3 Racing Engine™
Introduction
The TRX 3.3 Racing Engine is the next generation of TRX nitro power.
The larger displacement and advanced porting generate class-leading
horsepower while still maintaining the TRX Racing Engine characteristics of
broad, linear power delivery and ease of tuning. Focused engineering and
rigorous testing have yielded unprecedented power and uncompromising
performance that turns ready-to-run into Ready-To-Race®
.
Traxxas strongly
discourages changing or
modifying any part of the
TRX 3.3 Racing Engine. Old
tech tips and tricks that
may have boosted the
power of other engines
could seriously diminish
the performance of the
TRX 3.3 Racing Engine.
The TRX 3.3 Racing Engine takes a total-system approach. Each part of
the engine, from the air filter to the exhaust tip, is carefully engineered
to work in harmony with other engine components. Each part
complements the next, to extract maximum power. The TRX 3.3 Racing
Engine is designed to be tolerant of variations in tuning, and to run
successfully through a wide range of variable atmospheric conditions
such as changes in temperature, humidity, and altitude.
In order to get the longest engine life and keep the TRX 3.3 Racing
Engine in top running condition, it is very important to perform regular
routine maintenance. The number one cause of premature engine
wear and failure is lack of care and maintenance!
Break-In
The TRX 3.3 Racing Engine is manufactured to exacting tolerances and
requires a specially-designed break-in procedure to accomplish the final
precision fitting of the internal engine components. It is very important
that you follow the new break-in procedure as closely as possible to
achieve the best performance and longest life from your TRX 3.3 Racing
Engine. Engine break-in will take between one and two hours. Old style
break-in procedures, such as idling the engine on the bench for several
tanks of fuel or simply running the engine with a very rich fuel mixture
for the first 4 tanks of fuel, will not achieve the best results. Follow the
easy steps in this manual.
After-Run Maintenance
Perform after-run maintenance on the engine to prevent corrosion
from building up on the internal engine components. The fuel
naturally attracts moisture and corrosion can build up very quickly
inside the engine if it is not prevented.
There’s more advanced
thinking, development and
testing in the stock parts of
your TRX 3.3 Racing Engine
than in many aftermarket
manufacturer’s
performance parts. The
TRX 3.3 Racing Engine is
already the most powerful
engine in its class and may
not benefit from average,
low-tech, aftermarket bolt
on performance items.
A few minutes spent before and after each time you run your model
will allow you to enjoy it for a long time to come. Read on for more
exciting details about your new engine.
Air Filter Maintenance
A clean air filter is critical for long engine life. Due to the highperformance nature of the TRX 3.3 Racing Engine, a tremendous amount
of vacuum is created to move a large volume of high-velocity air through
the carburetor. Dirt is the worst enemy to your engine. Clean the air filter
after each hour of running to prevent sucking dirt into the engine. An
extra pre-lubed air filter element has been provided to encourage you to
maintain your air filter.
Nitro 4-Tec 3.3 • 17
The TRX 3.3 Racing Engine
TRX 3.3 Racing Engine Illustrated
Air Filter
Base
Idle Speed
Screw
Air Filter
Housing
Head Protector
PowerTune™ head
(Cylinder head)
EZ-Start Drive Unit
EZ-Start Motor
Low-Speed Needle
High-Speed
Needle
Throttle Arm
Fuel Intake
Engine Mount
Air Intake
Crankcase
Carburetor
Flywheel
Clutch Bell
Crankshaft
Glow Plug Wire
EZ-Start
Controller
EZ-Start Plug
Positive Wire
Ground Wire
Pressure Line
Negative Wire
Fuel Line
Engine Shut-off Clamp
Header
Tuned Pipe
Fuel Tank
18 • Nitro 4-Tec 3.3
The TRX 3.3 Racing Engine
Terms to Know
You’ll find these Nitro R/C engine terms throughout this section
of the manual.
.15 - .15 or “15” refers to the displacement of the engine. The TRX 2.5
Racing Engine is .15 cubic inches or 2.5 cubic centimeters (cc). The name
“TRX 2.5” is derived from the cc measurement.
.20 - .20 or “20” refers to the size of the engine. The TRX 3.3 is .20 cubic
inches or 3.3 cubic centimeters (cc). The name “TRX 3.3” is derived from
the cc measurement.
ABC - Abbreviation for aluminum, brass, and chrome. Refers to engine
construction that consists of an aluminum piston that slides in a chromeplated brass sleeve. The TRX 3.3 uses ABC construction.
Air filter - The air filter sits atop the carburetor and prevents harmful dust
and dirt from entering the engine. Dirt ingestion is the number one
cause of premature engine failure so the engine should never be run
without the air filter in place.
BDC - Bottom dead center. The bottom-most position of the engine
piston stroke.
Break-in - Break-in is the procedure for running a brand new engine
according to specific instructions. This correctly prepares the engine for
normal running. The break-in procedure can be different for different
makes of engines. Follow the Traxxas directions for break-in exactly.
Carb - Abbreviation for carburetor.
Carburetor - The carburetor atomizes (mixes) the fuel with the air so that
the engine can burn it. There are two types of carburetors; slide carbs
and barrel carbs. The TRX 3.3 uses the superior slide carburetor design.
Clean-out - Cleaning-out is a condition that occurs when the engine is
accelerating and the fuel mixture becomes sufficiently lean to allow the
engine to continue into its upper rpm power band. It is usually
characterized by a noticeable decrease in blue exhaust smoke and a
dramatic increase in engine speed.
Combustion chamber - The combustion chamber is machined into the
bottom of the cylinder head. This is where the glow plug ignites the fuel.
The shape of the combustion chamber is designed to promote more
efficient burning of the fuel.
Connecting rod - The connecting rod transfers the piston motion to the
crankshaft. The TRX 3.3 Racing Engine uses a “knife-edged” connecting
rod. The aerodynamic, sharpened edges allow it to “slice” through the
pressurized air/fuel mixture inside the crankcase.
Crankcase - The engine’s “body” that contains all of the running
mechanical components.
Crankshaft - The main shaft of the engine that holds the
reciprocating assembly.
Cooling fins - The cooling fins are milled into the cylinder head and
crankcase and cause heat to be drawn away from the engine. Heat is
removed when it dissipates into the air passing across the cooling fins.
It is important to keep the fins clean of dirt and debris for maximum
cooling efficiency.
Cylinder head (head) - The finned aluminum part on top of the engine
that is responsible for dissipating most of the engine’s heat. The
combustion chamber is machined into the bottom of the head.
Dyno - Abbreviation for dynamometer. A precise piece of testing
equipment that accurately measures engine power and torque output
over the engine’s entire rpm range.
EZ-Start - Traxxas on-board electric starting system. The system consists of
a hand held starter control unit and an on-board gearbox with an electric
motor to spin the engine.
Filter foam - The oiled foam element inside the air filter housing. The filter
foam in the TRX 3.3 must be thoroughly cleaned and re-oiled after every
hour of run time.
Fit - Usually refers to the fit of the piston and sleeve. If the fit is tight, the
piston will feel very tight at top of the sleeve (top dead center), and the
engine will have good sealing and compression. If the fit is loose,
compression will be low and both the piston and sleeve should be
replaced.
Flame-out - Occurs when the engine stops running at high rpm. Usually
the fault of an excessively lean fuel mixture or glow plug failure.
Fuel - (10%, 20%, 33%) The TRX 3.3 must have model engine fuel to run.
Traxxas Top Fuel™ is recommended. Fuel is sold in quarts and gallons
from hobby dealers. The 10%, 20% and 33% labeling refers to the
percentage of nitromethane contained in the fuel.
Fuel mixture - The ratio of fuel to air as determined by the needle settings
of the carburetor.
Fuel tubing (fuel line) - The thick silicone tubing that carries fuel
from the fuel tank to the carburetor.
Glow plug - The glow plug is located in the cylinder head at the top of the
combustion chamber. It contains an element that glows red hot when
voltage is applied. When the engine is being started, the heat from the
glow plug ignites the fuel mixture and starts the combustion process.
Nitro 4-Tec 3.3 • 19
The TRX 3.3 Racing Engine
Glow plug driver - This tool clips onto the glow plug and supplies the
required voltage to light the glow plug element. It is also called an
igniter. EZ-Start equipped engines do not require this separate tool.
Header - The aluminum tube that connects the exhaust system to the
engine exhaust port. The length and diameter of the header must be
carefully selected to extract the most power from the engine.
High-speed needle (HSN) - Adjusts the carburetors fuel/air mixture at
high throttle openings.
Idle speed - The speed (rpm) the engine runs at when the transmitter’s
throttle trigger is at neutral.
Idle speed screw (ISS) - Located on the carburetor body. This screw
adjusts the idle rpm of the engine.
Lean - A running condition where the engine is not getting enough fuel
(for the available air). Symptoms include engine overheating, or the
engine runs for a short time and then stalls, particularly at high speed.
This is a dangerous condition that should be corrected immediately or
it can ruin your engine.
Leaning the mixture - Turning either the high-speed and/or low-speed
needle(s) clockwise to decrease the amount of fuel the engine receives.
Low-speed needle (LSN) - Needle valve that controls the fuel mixture at
low throttle openings.
Needle valve - Valve consisting of a tapered needle that closes against a
corresponding seat to regulate fuel flow.
Nitro - Abbreviation for nitromethane, a component of model engine
fuel that improves fuel combustion and power output. Nitro also refers
to a class of R/C powered by model engines instead of electric.
Nitro content - The amount of nitromethane used in the fuel. Usually
measured as a percentage of the total fuel volume. Traxxas engines are
optimized to use 10-20% nitro. 33% nitro may be used for racing.
Nitromethane - Nitromethane is a component in the fuel that increases
power from the combustion process up to a point. Engines are
generally optimized to use a range of nitro content for the best power.
O-ring - Rubber “O”-shaped ring used as a sealing gasket.
Pipe - Abbreviation for the tuned exhaust pipe on a nitro engine.
See “Tuned Pipe”.
Piston - The piston is the internal engine part that is attached to the
upper end of the connecting rod and moves up and down in the
cylinder sleeve. The precise fit between the piston and the sleeve
creates a seal that allows the engine to have the required compression
for combustion.
20 • Nitro 4-Tec 3.3
Port - Ports are openings in the sleeve that allow atomized fuel to enter
the combustion chamber and burned exhaust gases to exit. The shape
and location of the ports are a large factor in controlling the engine
timing and power output.
Priming - Manually causing fuel to move from the fuel tank up to the
carburetor. This is sometimes necessary after the engine has been
sitting for a long period of time and all of the fuel has drained back to
the tank. On a Traxxas model this is done by holding your finger over
the exhaust tip for one or two seconds while the engine is starting.
Punch - A term that refers to how quickly the model responds to throttle
input or how quickly it accelerates.
Rich - A running condition where the engine is getting too much fuel for
the available air. It is better to run an engine slightly rich to increase
engine life. Excessively rich mixtures cause the engine to have sluggish
performance with exaggerated blue smoke and unburned fuel coming
from the exhaust.
rpm - Abbreviation for revolutions per minute (how many times the
engine crankshaft spins in a minute).
Sleeve - Internal engine part that contains the piston. The precise fit
between the sleeve and the piston creates a seal that allows engine to
have the required compression for combustion. The sleeve in a TRX
engine is made of brass and is then hard-chrome plated.
Slide carburetor - The throttle on a slide carburetor closes and opens by
sliding a barrel in and out of the carburetor body. This type of
carburetor is preferred for performance use because it provides a less
restrictive “straight-through” air path than the barrel carburetor design.
Stall - When the engine stops running, usually due to an incorrect fuel
mixture setting or running out of fuel.
TDC - Top dead center. The top-most position of the engine
piston stroke.
Tuned pipe - The tuned exhaust pipe usually consists of a speciallyshaped metal or composite chamber with baffles that is designed to
enhance the power output of the engine.
Wear-in - Fitment process that occurs during engine break-in where
internal engine parts develop an even more precise matched fit
through actual use under controlled circumstances.
WOT - Abbreviation for wide-open throttle.
The TRX 3.3 Racing Engine
The Fuel
Use the Right Fuel
It’s imperative that you use the correct fuel in your
TRX 3.3 Racing Engine for maximum performance
and engine life. Traxxas Top Fuel™ should be used
to ensure correct engine lubrication, performance,
and ease of tuning. Traxxas Top Fuel has been
proven in thousands of engines, so you can count
on it every day for great performance.
Top Fuel is the only fuel which is
100% certified for use in Traxxas engines.
Traxxas Top Fuel is made with just the right balance of the highest
grade natural and synthetic lubricants to allow excellent throttle
response and the best top-end performance, without sacrificing
long-term durability.
All of the components in the fuel are carefully selected from the
best materials available and then custom blended to match the
metallurgy and temperature characteristics of Traxxas engines.
You may use 10%, 20% or 33% nitro-content fuel. Try to use the same
percentage all the time, avoid switching back and forth between fuels.
We recommend that if you break in your engine on 20% fuel that you stick
with that percentage. If you do move to a higher or lower percentage,
make sure you readjust your fuel mixture to compensate (see below).
Choosing a Nitro Percentage
A commonly asked question is "what is the difference between 10%, 20%,
and 33% fuels?" Increasing the nitro in the fuel is almost like adding extra
oxygen to the combustion process. It burns more efficiently, improves
combustion, and delivers more power. When increased nitro is used, more
of the other fuel components are then required inside the combustion
chamber to maintain the perfect air/fuel ratio. Therefore, overall fuel
mixtures need to be richened slightly (on the high speed needle, about
3/4 of a turn counterclockwise when changing from 20% to 33%, about
1/2 of a turn counterclockwise when changing from 10% to 20%). This
allows greater fuel flow through the engine and promotes cooler running,
even at the maximum lean settings.
If 33% improves power, then it seems that the highest nitro content
available (beyond 33%) should always be used in the engine. In reality,
there are practical limitations. Engines are designed to run best within a
range of nitro percentages. How the engine is ported, the size of the
combustion chamber and other factors determine how much nitro can be
efficiently used in the engine. The TRX 3.3 Racing Engine responds
exceptionally well to a maximum of 33% nitro, returning cooler temps,
more power, and a smoother throttle response. For those who want to run
higher nitro, 33% Top Fuel is the optimum nitro percentage for the TRX
3.3 Racing Engine. Increasing the nitro beyond 33% can introduce the
need for engine modifications (ports, head shimming, etc.) to avoid
starting and tuning difficulties. There are limits to how much nitro an
engine can effectively use to make more power. Lower nitro percentages
have their own advantages. Nitro is an expensive component in the fuel
so 10% nitro blend is more economical for the sport user. 10% also
provides greater latitude with the needle settings for easier tuning.
When using Traxxas Top Fuel, using higher nitro percentages does not
cause the engine to wear out faster. 33% Top Fuel contains the same
quality lubrication package as 10 and 20% Top Fuel. Some non-Traxxas
high-percentage nitro racing fuels do sacrifice some lubrication in
attempts to increase performance. We urge you to not take chances with
your engine investment and use Top Fuel for consistent performance and
long engine life.
DANGER! Model engine fuel
is poisonous to humans
and animals. Drinking the
fuel can cause blindness
and death. Handle with
care and respect. Keep it
out of reach of small
children at all times! While
driving, do not leave your
fuel dispensing bottle on
the ground where a child
could have access to it.
Follow fuel label warnings.
What about Other Fuels?
Can other brands of fuel be used besides Top Fuel? There are other fuels
that can provide satisfactory performance; however there could be longterm costs in the form of decreased engine performance, loss of tuning
ease, and shorter engine life. Only use fuels that contain both castor and
synthetic oil.
Everyone has an opinion or a claim to make about fuel. The engineering
team at Traxxas has spent years developing TRX Racing Engines. No one
knows more about the specific fuel requirements of Traxxas engines,
than Traxxas engineers. We strongly urge you not to take chances with
your engine investment and use the Traxxas fuel made for the TRX 3.3
Racing Engine.
Handling the Fuel
Follow all directions and warnings on the fuel can.
Keep the fuel tightly capped at all times. Some components in the fuel
can evaporate very quickly and upset the balance of the fuel.
Do not store unused fuel in the fuel dispenser. Immediately return fresh
unused fuel back into the fuel can.
Do not mix old and new fuel. Never mix different fuel brands together.
Store the fuel in a cool dry location, away from any source of heat,
ignition, or combustion.
Read and follow the safety precautions on page 4 in this manual.
Nitro 4-Tec 3.3 • 21
The TRX 3.3 Racing Engine
Filling the Fuel Tank
Air Filter Cleaning Instructions
Use a fuel dispensing bottle (Traxxas Top Fueler, part#
5001) to put fuel into the Nitro 4-Tec’s fuel tank. To fill
the fuel bottle, squeeze the air out, insert the
dispenser tip into the fuel can, and release your
grip on the bottle. As the bottle expands, fuel will
be drawn into it.
1. Remove the air filter from the carburetor
bore by pulling the entire filter assembly
firmly to the side to release it. Do not pull
straight up.
To fill your model flip up the springloaded cap on the fuel tank, insert
the tip of the fuel bottle, and
squeeze to dispense the fuel. Fill the
tank until the fuel level reaches the
base of the filler neck. Close the fuel
tank lid, making sure it closes tightly.
The Air Filter
The TRX 3.3 Racing Engine air filter is specifically designed to deliver
maximum performance while protecting your engine from dust and dirt.
Use only the supplied filter. You will not improve engine performance by
switching to an aftermarket filter, and you may risk engine damage due to
poor filtration.
The TRX 3.3 Racing Engine air filter assembly consists of 3 pieces:
1. A rubber filter base.
2. A plastic housing consisting of a permanently
assembled mesh cap and body.
3. An oiled foam element.
You must clean the filter after every hour of run time, even if the filter
looks clean. This includes the break-in time. Clean your air filter after
break-in. Dust (which is often too fine to see) and dirt constantly move
through the filter anytime the engine is running. Even if you can’t see dirt
on the filter, it is present inside the foam after any amount of run time. If
you exceed the recommended cleaning intervals, your engine will be
damaged. Engine damage or wear due to dirt ingestion is easy to detect,
and one of the top causes of premature engine failure.
22 • Nitro 4-Tec 3.3
2. Disassemble the filter. Pull the rubber air
filter neck out of the filter body. With the
base removed, the foam element is visible
in the bottom of the filter body. Pull out the foam element.
3. Clean the filter parts by thoroughly washing all three pieces of the filter
assembly in hot soapy water (dishwashing detergent works well).
Repeat twice.
4. Thoroughly dry the parts with a clean towel or compressed air.
Remember to wear your safety glasses when working with
compressed air.
5. Oil the foam element with foam filter oil. Use the supplied Traxxas filter
oil (part# 5263) or a high-quality, special-purpose foam filter oil like
what is used for off-road motorcycle and ATV engines.This type of filter
oil is available at motorcycle pro-shops. Apply 30 drops of the Traxxas
filter oil evenly to the top, bottom and sides of the filter element (30
total drops divided among the 3 surfaces). Squeeze the filter element
repeatedly to help spread the oil throughout. The filter element should
be evenly colored by the oil. Even color indicates that the oil is
distributed evenly. Do not squeeze out excess oil.
Note: Do not use the air filter oil for anything other than the air filter.
It is not meant to be a lubricant.
6. Reassemble the filter and install it on the engine, making sure
the rubber filter neck fits securely on the carburetor with no gaps
or air leaks.
The TRX 3.3 Racing Engine
The Carburetor
Understanding the Carburetor adjustments
The carburetor performs several functions. It controls the engine’s speed
by restricting the intake of air and fuel into the engine. It atomizes the
fuel (suspends the fuel droplets in the air) and also controls the air/fuel
ratio of the mixture entering the engine (how much air for a given
amount of fuel).
molecules) to maintain the correct air/fuel ratio. Warmer air is less dense
(fewer air molecules) and therefore needs less fuel to maintain the
correct air/fuel ratio. The tuning needles are there to adjust how much
fuel is made available for the carburetor to mix with the available air
(atomization).
Cold Air (More Dense)
See page 30 for more
information on how
air density affects
engine tuning.
(Warm Air) Less Dense
A “turn” refers to
tightening (“turning in”) or
loosening (“turning out”)
mixture needles. A “full
turn” refers to turning the
needle 360°, so a “1/2 turn”
would be 180°, a “1/4 turn”
would be 90°, and so on.
Air
Fuel
Full Turn
360°
1/8 Turn
45°
Start
The Fuel Mixture Needles
To help provide a better understanding of engine tuning and why it’s
necessary, the following is a brief explanation of the air/fuel combustion
process that takes place inside the engine.
In order to create the cylinder pressure that results in power, the engine
burns the air/fuel mixture. Both air and fuel, in correct amounts, are
needed for proper combustion. It is the carburetor’s job to mix the air
and fuel together (atomize the fuel), in the correct proportion for the
best possible combustion. This is the ideal air/fuel ratio. The ideal air/fuel
ratio required for the engine remains roughly constant. Due to variations
in atmospheric conditions (temperature, humidity, altitude etc.) fuel flow
adjustment valves (called fuel mixture needles) are required to meter the
fuel and maintain the ideal air/fuel ratio in these ever-changing
conditions. For example, colder air is more dense (more air molecules)
for a given volume of air and therefore requires more fuel (more fuel
The amount of fuel metered and atomized by the carburetor is
controlled by the two mixture needles, the high-speed needle and the
low-speed needle. The low-speed needle is used to meter the fuel used
by the engine at idle and low rpm (part-throttle) engine speed. The highspeed needle is used to meter the fuel when the throttle is open from
part throttle to wide-open throttle (WOT). Two needles on the TRX 3.3
Racing Engine provide precise control of the air/fuel ratio across the
engine’s entire rpm range.
1/4 Turn
90°
3/4 Turn
270°
1/2 Turn
180°
The maximum possible fuel flow is always controlled by the high-speed
needle. It works like the main water valve on a garden hose. Turn it
clockwise to close the valve, counter-clockwise to open it. When the
throttle is at idle or partially open, the low-speed needle meters the fuel
flow at the outlet (needle seat) where the fuel enters the carburetor
venturi. This second valve acts like the spray nozzle at the end of the
garden hose in our example. When you accelerate from idle, the throttle
opens and the low-speed needle is pulled away from the needle seat.
This allows more fuel to flow with the increased air flow. As the throttle
Nitro 4-Tec 3.3 • 23
The TRX 3.3 Racing Engine
See Tuning Your TRX 3.3
Racing Engine on page 29
for complete information on
adjusting the air/fuel
mixture and idle speed.
Water Valve
Richen
(Controls Overall Flow)
High Speed Needle
Slightly rich fuel mixtures deliver cooler running and more
lubrication but with slightly less power.
Tuning the engine means finding the perfect balance between the two;
excellent power to meet your needs while maintaining good lubrication
for long engine life. The optimal fuel mixture setting is rich to provide a
safety margin against having a lean condition if some variable changes
(such as the temperature from one day to the next).
Factory Needle Settings
If your factory preset
carburetor adjustments
have been tampered with,
use the following settings:
Water Nozzle
• Set the high-speed needle
to 4 turns out from closed.
• Set the low-speed needle
so the screw head (red in
Fig. A) is flush (even) with
the end of the slide (yellow
in Fig. A).
Fig. A
Low Speed
Needle Adjustment
Always use the factory
settings for initial starting.
Only use these settings
when the factory settings
have been lost.
Higher nitro requires a
richer fuel mixture. When
running 33% fuel, richen
your high speed needle 3/4
turn if previously running
20% nitro and then re-tune
the engine for maximum
performance.
24 • Nitro 4-Tec 3.3
Slightly lean fuel mixtures deliver stronger, more efficient
combustion and more power, but with less lubrication.
(Controls Fine Flow)
Low Speed Needle
is increased, the low-speed needle is pulled completely away from the
needle seat leaving it fully open. At that point, fuel metering is entirely
controlled by the high-speed needle. Again, using our water hose
example, when the spray nozzle at the end of our garden hose is fully
open, then the main water valve can be used to adjust how fast the
water flows.
The engine’s performance is directly linked to the fuel mixture.
Richening the fuel mixture increases the amount of fuel in the air/fuel
mixture ratio and leaning the fuel mixture decreases the amount of
fuel in the air/fuel mixture ratio.
Lean
Rich
General fuel mixture settings are measured by the number of turns the
needles are turned out from fully closed. The fuel mixture settings have
been pre-set from the factory to typical break-in settings. Do not
readjust your carburetor from the factory settings until after the engine
is started and running, and you have been able to observe the engine
running to assess what minor adjustments may be required to
compensate for fuel, temperature, and altitude. Adjustments are usually
made in 1/8 or 1/16-turn increments. If the engine sticks at TDC, see
page 37 for instructions on freeing the engine.
The Idle Speed Adjustment
The idle speed screw controls the closed position of the throttle slide.
When the throttle servo is in its neutral position, the throttle slide should
be stopped against the idle adjustment screw. Always use the idle speed
adjusting screw to control engine idle. Do not use the throttle trim on
the transmitter to adjust idle speed. The idle speed should be set as low
as possible and still maintain reliable running.
The TRX 3.3 Racing Engine
The Traxxas EZ-Start Electric Starting System
The Traxxas EZ-Start brings the convenience of push-button electric
engine starting to your Nitro 4-Tec. The EZ-Start consists of a hand-held
control unit and an on-board motorized starter.
Power for the EZ-Start system comes from a 7.2-volt rechargeable
battery pack installed in the hand-held control unit (battery
sold separately).
The engine glow plug is heated automatically by the EZ-Start system,
eliminating the need to keep up with a separate glow plug igniter.
The voltage to the glow plug is kept constant, regardless of the load
placed on the starter by the starter motor.
The “Glow Plug” LED (light emitting diode) on the control unit
indicates the condition of the glow plug.
The “Motor” LED indicates the status of the EZ-Start electric
starter motor.
The cush drive mechanism in the drive unit prevents damage to the
gears caused by engine kickback.
™
Smart Start protection circuitry prevents damage to the motor by
cutting power if the load on the motor or other electronics exceeds
safe limits.
Installing the EZ-Start Battery
The EZ-Start system requires a fully charged 7.2-volt rechargeable NiCad
or NiMH battery pack (not included). Use a charger (not included)
designed for 7.2-volt battery packs. Charge the battery according to the
charger manufacturer’s directions.
1. Press the tab in the end of the battery
compartment door to open.
2. Plug a fully charged 7.2-volt
battery pack into the
connector inside.
3. Twist the battery two or three
times to twirl the battery plug
wires. This helps hold the wire
and battery in place when the
battery is installed in the
compartment.
B
A
C
D
4. Install the battery into the
compartment and press the wires
securely into place.
5. Snap the battery compartment door back on and lock the end tab.
Use the Right Charger:
The most convenient type
of charger is an AC peakdetecting charger that
plugs directly into an AC
wall outlet, such as the TRX
Power Charger (part #3030X,
see www.Traxxas.com for
more info). It contains
special peak-detection
circuitry that automatically
shuts the charger off when
the battery is fully charged.
If you’re using a 15-minute
timed charger, always fully
discharge the battery pack
before each charge. Some
high mAh battery packs
(1500 mAh or higher)
require more than the
standard 15 minutes of
charge time. If the battery
pack is cold after 15
minutes of charging, add
another 5 minutes of charge
time. Closely monitor the
battery pack and stop
charging it when it begins
to feel warm to the touch.
Never leave a battery
charging unattended.
Always follow charger
manufacturer’s instructions.
Inexpensive overnight wall
chargers may also be used.
Nitro 4-Tec 3.3 • 25
The TRX 3.3 Racing Engine
Using the EZ-Start
off the power to the motor. Allow at least 3 minutes for the starter motor
to cool and the circuit to automatically reset before continuing. Use the
time to find and eliminate the condition that caused the excessive load
on the starter motor.
Glow
Plug
Motor
Glow
Plug
Glow
Plug
A weak starter battery, or one that has not been fully charged, may not
deliver enough power to crank the engine over at the appropriate rpm
to keep the piston from sticking at top dead center (TDC). A new engine
will typically have a tight fit between the piston and the top of the
sleeve. This is a tapered fit, and a tight piston sleeve fit on initial startup
is desirable for those who want the best-performing engine. Make sure
you are using a good quality battery pack that is fully charged (new
batteries usually require several charge cycles to reach peak voltage and
full capacity). This is especially important with a new engine that needs
to be broken in. If the engine sticks at TDC, see page 37 for instructions
on freeing the engine.
Motor
Motor
Glow
Plug
If the Glow Plug LED fails to light,
the glow plug may be bad, or the
glow plug wire may be damaged
or disconnected.
Motor
Use a Strong Starter Battery
Each of the two status indicator LEDs on
the hand-held control unit, the Motor
LED and the Glow Plug LED, should
light green while starting. If either LED
fails to light while starting, there is a
fault indicated with that function:
Glow
Plug
Glow
Plug
Motor
It’s normal for your EZ-Start
controller to become warm
after repeated use.
Your EZ-Start controller plugs into a 4-prong receptacle in the center of
the rear deck on your Nitro 4-Tec. When the red button on the controller
is pressed, the EZ-Start motor begins to spin the engine and power from
the control unit heats the glow plug. Assuming all settings and
preparations are correct, the engine should start almost immediately.
Motor
When the EZ-Start
controller is in protection
mode, wait at least three
minutes before attempting
to start the engine, to give
the starter motor time
to cool.
Protection Mode
The EZ-Start uses Smart Start™ technology to monitor the condition of
the system and detect failures. The controller monitors the load being
placed on the EZ-Start motor. If the load becomes excessive, the system
shuts off power to the motor to prevent costly damage to the motor and
the controller. This may occur, for example, if the engine floods with fuel
during starting. The starter spins at first but when excessive fuel in the
combustion chamber begins to lock up the engine, the starter motor
slows under the heavier load. This causes the protection circuit to shut
26 • Nitro 4-Tec 3.3
Glow
Plug
Turning off the switch for the radio will
not shut off the engine. To shut off the
engine, use the shut-off clamp on the fuel
line. Squeeze the clamp closed to shut off
the fuel supply to the engine. Don’t forget
to release it when you restart the engine.
Motor
Glow
Plug
Glow
Plug
Motor
If the Motor LED fails to light and
the starter fails to operate, then the
EZ-Start is in protection mode.
Motor
Shutting Off The Engine
Avoid shutting off the engine by placing your finger over the exhaust
outlet, especially if you are through driving for the day. This will leave
more unburned fuel in the engine that could lead to harmful corrosion.
Always be careful not to touch the exhaust pipe after running, it can
become very hot.
The TRX 3.3 Racing Engine
Breaking in Your TRX 3.3 Racing Engine
The TRX 3.3 Racing Engine uses a ringless, aluminum-brass-chrome (ABC)
piston/sleeve construction. This type of engine design relies on a very
precise running fit between the piston and sleeve for cylinder sealing.
Engine break-in is necessary to allow the piston and sleeve to develop
an extremely precise fit and optimum cylinder sealing. Therefore,
proper engine break-in is critical to achieving the fastest, most reliable
engine performance.
Allow yourself about 1 to 11/2 hours to complete the break-in procedure.
The engine break-in period will take 5 tanks of fuel in a Nitro 4-Tec. The
break-in time is not the time to impress your friends with your new Nitro
4-Tec. You must wait until the engine is fully broken in before
attempting sustained high speed running. Patience and careful
attention during break-in will reward you with the best-performing TRX
3.3 Racing Engine possible.
During break-in, your engine may appear to malfunction with symptoms
like stalling, inconsistent performance, and fouled glow plugs. These are
simply the normal “break-in pains” engines sometimes go through. They
will disappear once your engine is fully broken in. Many owners report
not experiencing any of these symptoms with TRX Racing Engines. We
recommend to go ahead and replace the glow plug with a new one
after the engine break in procedure.
Engine Break-in Procedure
The focus during break-in is to vary and limit the engine speed. This will
be accomplished by accelerating and stopping at different rates for the
first 5 tanks of fuel. As the engine begins to break-in, the duration and
intensity of the acceleration will gradually increase. Sustained highspeed running is not permitted until the 6th tank of fuel. Perform the
initial break-in on a large, flat, paved surface. Nitro 4-Tec is very fast and
by tanks 4 and 5 you will need plenty of room for the car to run in.
Apply all throttle and braking actions gently. Abrupt acceleration or
braking could cause the engine to stall unnecessarily.
Special break-in fuels are not recommended. Use the same fuel you
plan to use everyday.
If possible, avoid breaking-in the engine on extremely hot or cold days
(see page 29).
Pay careful attention to the fuel level. Do not allow the fuel tank to run
completely empty. An extremely low fuel level causes the mixture to
run too lean. This could result in a burned glow plug or extremely high
engine temperatures.
Do not attempt to break in the TRX 3.3 Racing Engine by idling it on a
stand. This will produce poor results.
Keep extra Traxxas glow plugs handy. The break-in process can cause
deposits to form on the plug leading to plug failure.
Change or clean your air filter after break-in.
Follow the instructions exactly for each of the first 5 tanks of fuel.
Starting Your TRX 3.3 Racing Engine for the First Time
Before you start your TRX 3.3 Racing Engine for the first time, make sure
you have read all instructions and precautions in this manual. Pay close
attention to the tank-by-tank break-in instructions in the next section,
and make sure you have read and understood them before you run
your engine.
Your engine must be at room temperature (70°F or 21° C) or above the
first time you start it. If it’s cooler than room temperature outside, remove
all fuel and keep your Nitro 4-Tec indoors until you’re ready to start it and
then take it outside. If it’s colder than 45 degrees, special considerations
should be made. See cold weather break-in on page 29. We do not
recommend running the model in temperatures below 35 degrees.
1. Turn on the radio system (see page 15).
2. Make sure the throttle trigger on the
transmitter is in the idle (neutral) position.
3. Connect the EZ-Start controller according to
the instructions on page 26.
4. Press the starter button in short two second
bursts and watch for fuel moving through the
fuel line up to the carburetor. Watch closely!
The fuel moves very fast. If the fuel doesn’t
move through the line within 5 seconds, prime the engine by briefly
(one or two seconds) covering the exhaust outlet with your finger until
the fuel is just visible in the carburetor fuel line. Watch carefully! If the
engine is primed too long, it will flood with fuel and stop turning.
5. Once fuel reaches the carburetor, the engine should
quickly start and idle.
6. Disconnect the EZ-Start controller from the model.
7. Proceed with the engine break-in.
8. Do not rev your engine with no load (wheels off the ground).
If your engine doesn’t start, go online to www.traxxas.com/support. If your
factory fuel mixture settings have been altered, refer to page 24. If you still
have problems, contact Traxxas Customer Support at 1-888-TRAXXAS or
support@traxxas.com.
See Important Points to
Remember on page 4 for
other precautions.
Never run your Nitro 4-Tec
indoors. Since the TRX 3.3
Racing Engine exhaust
fumes are harmful, always
run your model outdoors, in
a well-ventilated area.
Your TRX 3.3 Racing Engine
doesn’t usually require
priming. If you do need to
prime your engine, watch
the fuel line carefully to
avoid flooding your engine.
See page 37 for information
on clearing a flooded engine.
Factory Needle Settings:
Your carburetor is preset at
the factory to give the
correct air-to-fuel ratio and
idle speed for engine breakin. Do not adjust the
carburetor unless you
observe a poor running
condition that requires
correction (see page 24 for
stock settings).
Higher nitro requires a
richer fuel mixture. When
running 33% fuel, richen
your high speed needle 3/4
turn if previously running
20% nitro and then re-tune
the engine for maximum
performance. See page 21
for more information.
Nitro 4-Tec 3.3 • 27
The TRX 3.3 Racing Engine
High Altitude Operation:
If you live in a high
altitude region (5000 or
more feet above sea level),
the lower air density may
require you to lean your
high-speed fuel mixture
slightly from the factory
break in settings. Try this
if you are experiencing
difficult starting or
extremely sluggish
engine performance at
high altitude.
As you gain experience in
the hobby, you may
discover that many people
have differing opinions on
what is the proper
procedure to break-in a
model engine. Only use the
Traxxas break-in procedure.
Other break-in procedures
could result in a weak,
damaged, or otherwise poor
performing engine. The
procedure outlined here
was extensively tested and
proven to yield better
performing engines than
other “common” break-in
methods. Even if you have
years of experience using
model engines, please do
not ignore this caution!
28 • Nitro 4-Tec 3.3
Tank 1
1. Drive the model with the body off.
2. Driving procedure: Gently pull the throttle trigger to 1/4 throttle over
a 2-second count. Then gently apply the brake to stop. Count the two
seconds out while accelerating: one thousand one, one thousand two,
and then stop. Operate the throttle trigger as smoothly as you can.
Repeat this starting and stopping procedure until the first tank of
fuel is nearly empty.
3. Look for thick blue smoke exiting the exhaust outlet. If there is
no smoke, richen the high-speed needle 1/4 turn, by turning the needle
counterclockwise.
4. When the fuel tank is nearly empty, shut off the engine by pinching the
fuel line connected to the carburetor (use the installed clamp).
5. Let the engine cool for 15 minutes.
Note: If at any point the engine cuts out or stalls during gentle
acceleration, richen the high-speed needle 1/4 turn by turning the needle
counterclockwise.
Tank 2
1. From tank 2 forward, Nitro 4-Tec should be driven with the body on.
2. Driving procedure: Gently pull the throttle trigger to 1/2 throttle over
a 2-second count. Then gently apply the brake to stop. Count the two
seconds out while accelerating: one thousand one, one thousand two,
and then stop. Repeat this starting and stopping procedure until the
second tank of fuel is nearly empty.
3. When the fuel tank is nearly empty, shut off the engine and let it cool
for 15 minutes.
Tank 3
1. Driving procedure: Gently pull the throttle trigger to 1/2 throttle over
a 3-second count. Then gently apply the brake to stop. Count the
three seconds out while accelerating: one thousand one, one thousand
two, one thousand three, and then stop. Repeat this starting and
stopping procedure until the third tank of fuel is nearly empty.
Tank
Throttle
1
2
3
4
5
1/4
1/2
1/2
Full
Full
Time
2
2
3
3
5
Seconds
Seconds
Seconds
Seconds
Seconds
2. As the engine loosens, the idle speed may increase and cause
the model to try to creep forward when stopped. Reduce the
idle speed by turning the idle adjustment (see page 18) on the
carburetor counterclockwise.
3. When the fuel tank is nearly empty, shut off the engine and refuel.
From here on, you do not need to let the engine cool between tanks.
Tank 4
1. Driving procedure: Gently pull the throttle trigger to full throttle over
a 3-second count. Then gently apply the brake to stop. Count the
three seconds out while accelerating: one thousand one, one thousand
two, one thousand three, and then stop. Repeat this starting and
stopping procedure until the fourth tank of fuel is nearly empty.
2. Apply the throttle gradually! Your finger should not reach full throttle
until the end of the three-second count. Nitro 4-Tec may try to shift into
second gear. If it does, reduce the throttle input. Do not let Nitro 4-Tec
shift out of first gear.
3. Keep your driving smooth and consistent.
4. When the fuel tank is nearly empty, shut off the engine and refuel.
Tank 5
1. Driving procedure: Gently pull the throttle trigger to full throttle over
a 3-second count, hold for 2 more seconds, and then gently apply
the brake to stop. Count the five seconds out while accelerating.
Repeat this starting and stopping procedure until the fifth tank of
fuel is nearly empty.
2. The model should now be shifting into second gear. If it is not, try
turning the high-speed needle clockwise 1/8 turn to lean the fuel
mixture slightly and test for shifting.
3. When the fuel tank is nearly empty, shut off the engine and refuel.
Tank 6
STOP! Clean your air filter before you proceed. Refer to the instructions
on page 22. During the sixth tank of fuel, the engine can be tuned
for general performance use. Proceed to the next section in this manual.
Cool
Body
15 Minutes
15 Minutes
-
Off
On
On
On
On
Notes
Apply throttle gradually.
Apply throttle gradually.
Reduce idle speed if necessary.
Do not allow shifting to high gear.
Accelerate over 3 second count, hold for 2 seconds.
The TRX 3.3 Racing Engine
Winter Break-in Tips
During the break-in process, the piston and sleeve wear into each other to
form a precise fit. The engine needs to heat up to a temperature around 200
to 215 degrees to allow the piston and sleeve to achieve this fit properly. A
precise fit between these two components is critical for proper compression,
and optimum performance. If the engine runs too cold during break-in, the
piston and sleeve will not expand to their appropriate sizes for break-in, and
this can lead to premature wear of these components. This wear may not
become apparent until after winter has past, and the engine is operated
under warmer running conditions.
Warm the engine to approximately room temperature by removing
all fuel and storing the vehicle inside at room temperature until just
before starting the engine. An extremely cold engine can become
difficult to start.
After the engine is running, it is important to keep the temperature of
the engine up around 200 to 215 degrees during break-in. In weather
below 45 degrees, the TRX 3.3 Racing Engine will tend to run at lower
temperatures between 160 to 180 degrees (when tuned at proper breakin mixture settings). This is too cool for break-in. Do not lean the fuel
mixture to increase engine temperature! This will also decrease
lubrication and cause your piston/sleeve to wear prematurely.
Wrap the cooling head with a paper towel,
clean rag or sock to help keep the engine
running around the recommended 200 to 215
break-in temp. If too much heat is contained,
the engine can actually run too hot. Make sure
that you monitor the engine's temp closely for
the first couple of tanks until you get the right
amount of cover for the cooling head. This will,
of course, depend on your current weather conditions. Adjusting the
cover up and down, exposing more or fewer cooling fins, is a convenient
way to regulate engine temps.
For owners that do not have access to a temperature probe, a drop of
water on the cooling head (around the glow plug area) should slowly
sizzle for approximately 6 to 8 seconds around 200 to 210 degrees. If the
water sizzles for only a few seconds, then it is likely that it is over 220
degrees, and needs to cool down. If the water takes a long time or does
not evaporate at all, then the engine is too cool.
We do not recommend that you operate your engine below 35 degrees
Fahrenheit. If you insist on running your vehicle below 35 degrees, be
aware that nitro engines may be very difficult to start and tune at
extremely cold temperatures. Also, at temperatures below freezing, nitro
fuel can actually begin to gel up, and this can be harmful to the engine.
Follow the remaining break-in procedures as outlined in this Owners
Manual. This, along with the steps listed above, will ensure a good break-in
for your new nitro engine, and provide many hours of enjoyment.
Tuning Your TRX 3.3 Racing Engine
The engine’s performance
depends on the fuel mixture.
Turn the mixture needles
clockwise to lean the fuel
mixture and counterclockwise
to richen it. Leaning the fuel
mixture will increase engine
power up to the engine’s
mechanical limits. Never run
the engine too lean (not
enough fuel flow). Never
lean the engine until it
begins to cut-out or stall.
Leaning the engine beyond
the safe allowable limits will
result in poor performance
and almost certain engine
damage. Indications of an
overly lean mixture include:
When tuning for
performance, watch closely
to notice when there is no
longer any increase in speed
or power when the
high-speed mixture is lean.
If you lean the high-speed
mixture to the point that the
engine cuts-out, hesitates,
or stalls, you are well into
the danger zone and engine
damage is likely. Richen the
high-speed needle 1/4 turn
and retune.
For your convenience, the
low-speed needle has a
positive stop that prevents
it from being over tightened
and damaging the needle
and seat. This also provides
an easy way to gauge how
many turns out from closed
the low-speed needle
adjustment is set to.
Cutting out or sudden loss of power during acceleration.
Overheating (temperature beyond 270° F at the glow plug).
Little or no blue smoke coming from the exhaust.
If any of these conditions are present, stop immediately and richen the
high speed mixture 1/4 turn. The engine will probably be slightly rich at
that setting and you can then retune for performance. Always tune for
performance by starting rich and moving leaner toward the ideal setting.
Never try to tune from the lean side. There should always be a light
stream of blue smoke coming from the exhaust.
Nitro 4-Tec 3.3 • 29
The TRX 3.3 Racing Engine
When adjusting the low
speed fuel mixture, it is
very important to make
several high-speed runs
with Nitro 4-Tec between
adjustments to clear out
any excess fuel. Perform
the pinch test immediately
after. If the engine is
allowed to idle for a long
period of time, it could
“load up” with fuel and
give you an inaccurate
measurement from your
pinch test.
Higher nitro requires a
richer fuel mixture. When
running 33% fuel, richen
your high speed needle 3/4
turn if previously running
20% nitro and then re-tune
the engine for maximum
performance. See page 21
for more information
Before you begin tuning, the engine should be warmed up to its normal
operating temperature and running slightly rich. All final tuning adjustments
must be made to the engine at its normal operating temperature. You can
tell the engine is running rich by noting any of the following:
Sluggish acceleration with blue smoke coming from the exhaust.
Nitro 4-Tec may not shift into second gear.
There is unburned fuel spraying from the exhaust tip.
Leaning the high-speed fuel mixture increases performance.
Richen the fuel mixture to the optimum setting by richening the highspeed needle at least 1/8 turn counterclockwise and retest. This setting
will extend engine component life.
High-Speed Fuel Mixture Adjustment
Low-Speed Fuel Mixture Adjustment
With the engine warm and running at a rich setting, gradually lean the
high-speed fuel mixture in 1/16 turn increments. Make several highspeed passes after each adjustment to clear out the engine and note any
change in performance. The TRX 3.3 is extremely powerful. Remember to
apply the throttle gradually to prevent spin-outs or loss of control.
Continue this procedure until there is no longer any performance
improvement. If any one of the following conditions occurs, the fuel
mixture is already past the maximum safe lean setting:
The low-speed mixture is always set after the high-speed needle is correctly
adjusted. The low-speed mixture is set using the pinch test.
1.
2.
3.
4.
There is no longer any performance improvement.
The engine begins to cut out at high speed (Danger!).
There is a sudden loss of power during acceleration (Danger!).
The engine begins to overheat. Symptoms of overheating include:
Steam or smoke coming from the engine (not exhaust).
Hesitation or stalling during acceleration.
Popping or clattering sound when decelerating (detonation).
Fuel Mixture Adjustment Chart
If the...
is..
Humidity
Pressure (barometer)
Temperature
Altitude
Nitro %
30 • Nitro 4-Tec 3.3
Fluctuating idle speed.
Temperature measurement above 270° F at the glow plug
(A temperature reading above 270° alone does not necessarily
indicate overheating. Look for other symptoms of overheating
combined with temperature for a more accurate warning).
Lower
Higher
Lower
Higher
Lower
Higher
Lower
Higher
Lower
Higher
1. Once the engine is warm, do several high-speed runs to confirm
that the high-speed needle is set correctly.
2. Bring the vehicle in and pinch closed the fuel line going into the
carburetor (use the engine shut-off clamp). The engine should run for 2-3
seconds, speed up, and then shut off.
3. If the engine runs longer than 3 seconds, then lean the low-speed needle
1/16 turn, make several more high-speed runs, and retest.
4. If the engine shuts off immediately without speeding up, then richen the
low-speed needle 1/8 turn, make several more high-speed runs, and retest.
When the low-speed needle is set correctly, the engine’s throttle response
should be very quick, even to the point of making it difficult to keep Nitro 4Tec from doing a wheelie when you accelerate!
then the air density is...
Slightly more dense
Slightly less dense
Less dense
More dense
More dense
Less dense
More dense
Less dense
adjust (correct) the
fuel mixture to be...
Slightly richer
Slightly leaner
Leaner
Richer
Richer
Leaner
Richer
Leaner
Leaner
Richer
The TRX 3.3 Racing Engine
Idle Speed Adjustment
Once the high and low-speed mixtures have been set, reduce the idle speed
to the minimum reliable idle speed. Remember, this adjustment should be
made while the engine is running at normal operating temperature.
1. Turn the throttle trim on the transmitter so the brakes are
applied (note its original position). This ensures that the throttle
slide is resting against the idle adjustment screw.
2. Turn the screw counterclockwise to reduce the idle speed, or clockwise to
increase it. The idle speed should be set as low as possible while still
maintaining reliable running characteristics.
3. Reset the throttle trim on the transmitter to its original position.
Fine-Tuning the Carburetor
After fine-tuning your TRX 3.3 Racing Engine at the end of the break-in
procedure, no major adjustments to the fuel mixture are usually necessary.
Make note of the temperature, humidity, and barometric pressure at the
time you finished fine tuning your carburetor. Current weather conditions
can be found online from national websites, local TV news websites, and
television. This information will be considered your baseline setting.
You may need to adjust your carburetor needles to compensate for changes
in temperature and barometric pressure (air density) from day to day.
Generally, you’ll need to richen the fuel mixture when the weather is colder
than your baseline temperature and the air density is higher. Lean the fuel
mixture when weather is warmer than your baseline temperature and the air
density is lower. The chart on page 30 provides general guidelines on how
weather conditions affect air density when they move higher or lower than
your baseline setting (see page 23 for detailed info on how air density affects
mixture settings).
Tuning the Engine by Temperature
The following procedures require an optional
infrared temperature probe or on-board temperature
gauge (Traxxas on-board digital temperature gauge,
part #4091). Engine temperature can be used as an
effective tuning aid when you understand the relationship between engine
temperature and ambient temperature. The engine operating temperature,
when tuned for maximum performance, will vary according to atmospheric
conditions, engine load, gauge accuracy, and many other factors. The
atmospheric condition that has the most influence on engine temperature is
air temperature. Expect the engine temperature to vary almost in direct
proportion to air temperature. Assuming you tuned the engine for the same
maximum performance each day, the engine will run about twenty degrees
hotter when it’s ninety degrees outside than it would in seventy-degree
weather. For this reason, we cannot give you a definitive temperature range
that indicates the best possible engine tuning.
There is NO optimal temperature that can be used as a target to deliver
the best engine tuning. Do not rely on a temp gauge alone to tune your
engine. Tune the engine by paying very close attention to how it
responds to changes in fuel mixture (more smoke/less smoke,
fast/sluggish, reliable/stalling, smooth sound/ muffled sound, etc).
Once the engine is tuned, then observe the temperature.
The temperature gauge can aid you in tuning by giving you a relative
indication of how your adjustments are affecting the engine and to help
prevent you from reaching excessive engine temperatures. For example, as
you lean the fuel mixture, the engine performance will increase along with
the temperature. If you continue to lean the fuel mixture and the
temperature increases but the engine performance does not change, then
you have exceeded the maximum safe lean setting. Make note of the engine
temperature. Generally, try to keep your engine from exceeding 270°F when
measured at the glow plug. If necessary,
increase airflow to the engine by cutting
out the windshield. In some situations,
the engine may perform very well with
no stalling, lagging, or hesitation at
temperatures above 270°F, particularly
in very hot climates.
If richening the fuel mixture to bring the temperature down to 270°F results
in poor, sluggish performance (engine never cleans out) then return the
engine back to a satisfactory state of tune based on how it sounds and
performs (always with a visible stream of blue smoke coming from the
exhaust). If engine temperature is exceeding 270°F with proper cooling and
no signs of abnormal running, then avoid running the engine at its
maximum lean setting. Watch closely for any signs of overheating. Richen
the fuel mixture slightly to provide a safety margin of additional cooling
lubrication. Symptoms of overheating include:
Steam or smoke coming from the engine (not exhaust).
Hesitation or stalling during acceleration.
Popping or clattering sound when decelerating (detonation).
Fluctuating idle speed.
Nitro 4-Tec 3.3 • 31
Driving Your Nitro 4-Tec 3.3
Introduction
Your TRX 3.3 Racing Engine is broken in, the fuel mixture is balanced, and
the idle is set…now it’s time to have some fun! This section contains
instructions on making adjustments to your Nitro 4-Tec. Before you go
on, here are some important precautions to keep in mind.
Don’t run your Nitro 4-Tec in water, mud, snow, or wet grass.
Water and mud are easily drawn through the air filter and will
severely damage the engine. Small amounts of moisture can cause
electronics to fail and loss of control over your Nitro 4-Tec.
The TRX 3.3 Racing Engine is extremely powerful. Remember to apply
the throttle gradually to prevent spin-outs or loss of control.
Don’t hold the Nitro 4-Tec off the ground and rev the engine
excessively with no load on the engine. This practice could result in
internal engine damage.
Avoid excessive high-speed running for extended periods of time or
over long distances. This could cause the engine to build up enough
speed to exceed maximum safe RPM limits.
Don’t drive your Nitro 4-Tec with drive train damage of any kind. The
engine could be damaged due to overloads on the engine caused by
drivetrain friction, or over-revving caused by loose or missing parts.
Don’t tow anything with your Nitro 4-Tec. The engine is cooled
by airflow created by speed. Towing creates a high load on the
engine, and at the same time limits cooling of the engine due to
low vehicle speed.
If your Nitro 4-Tec gets stuck, stop driving immediately. Move the
vehicle and then continue driving.
Never turn off the radio system while the engine is running. The car
could run out of control.
32 • Nitro 4-Tec 3.3
Not a Toy! For Expert Drivers Only! This product is capable of
extreme speed and acceleration! It carries our highest skill level
rating (5) and is intended for expert drivers only. Experience with
nitro-powered radio controlled models is required. The driver must
exercise all caution and accept full responsibility for their own
safety, and the safety of others nearby. Full-speed operation requires a large,
smooth running area free of obstacles and closed off to pedestrian and
automobile traffic.
WARNING! NOT A TOY! Read carefully! This product is capable of
extreme speed and acceleration! It is intended for expert drivers only.
Experience with nitro-powered radio controlled models is required.
The driver must exercise all caution and accept full responsibility for
their own safety, and the safety of others nearby. Full-speed operation
requires a large, smooth running area free of obstacles and closed off
to pedestrian and automobile traffic. This product is not designed for
children under 16. Responsible adult supervision is required during
operation and maintenance. For outdoor use only.
Nitro 4-Tec 3.3 is very fast and carries our highest skill level rating of 5
(Expert. For experienced drivers only!). Prior experience with R/C models
is required. Nitro 4-Tec 3.3 is a high-performance model which is NOT
intended for use on public roads or in congested areas where its
operation may conflict with or disrupt pedestrian or vehicular traffic.
Read all enclosed information before operating. Fully illustrated, step-bystep instructions describe adjustment and required maintenance
procedures. Nitro 4-Tec 3.3 should not be operated in a crowd, indoors or
without adequate space and ventilation. The vehicle is fully assembled,
ready-to-run, and requires the following items for operation: 12 AA
alkaline batteries, model car fuel, a 7.2 volt rechargeable battery pack,
and a charger. These items are available from your hobby dealer. In an
effort to continually upgrade our products, Traxxas reserves the right to
make improvements and modifications to this model, which may not be
reflected in the photographs and specifications printed in this manual.
Before running your Nitro 4-Tec 3.3, look over this entire manual and
examine the car carefully. If for some reason you decide Nitro 4-Tec 3.3 is
not what you wanted, then do not continue any further. Your hobby
dealer absolutely cannot accept a Nitro 4-Tec 3.3 for return or exchange
after it has been run.
Adjusting Your Nitro 4-Tec 3.3
Once you become familiar with driving your Nitro 4-Tec 3.3, you may
wish to make adjustments for better driving performance.
0°
0°
7. Use 1/8 turn increments to find the approximate, desired shift point.
8. Check performance by running a test lap after each adjustment.
-1°TOpoint.
9. Use 1/8-1/16 turn increments to fine tune the shift
-2°
Adjusting the Shift Point
The Nitro 4-Tec comes equipped with a two-speed transmission. When
the shift point on this transmission is adjusted correctly, it will
maximize acceleration, improve drivability, and minimize lap times. Use
a 2.0mm hex wrench to adjust the shift point.
1. Stop engine.
2. Rotate the drum until the access hole is visible from the top.
3. Hold the spur gear set, and roll
the car forward while looking
Access
Hole
through the access hole. Note
Drum
that you will see two set screws
through the access hole as you
roll the car forward. The first one
holds the two-speed mechanism
to the shaft. Do not loosen this
screw unless you want to
remove the two-speed
mechanism. The second is the
adjustment set screw. Refer to the drawing to identify the screws.
4. Insert a 2.0 hex wrench through the clutch drum and into
the adjustment set screw. (See diagram)
5. Turn the adjustment screw clockwise
to raise the shift point (later shifts).
Be careful not to overtighten the
adjustment screw or you may
damage the tension spring.
6. Turn the adjustment screw counterclockwise to lower shift point (earlier
shifts). Be careful not to loosen the
adjustment screw too much or you
may cause the screw and spring to
fall out.
Alignment Specs
The Nitro 4-Tec is supplied with soft-compound, race-quality tires. Due
to the high power output of the TRX 3.3 Racing Engine and the high
performance nature of the tires, suspension alignment is critical to
achieving maximum tire life. Proper alignment promotes even and
consistent tire wear as well as predictable and balanced handling.
Camber
The camber angle of both the front and
Front
rear wheels can be adjusted with the
Camber
camber rods (upper turnbuckles). Use a
square or right-angle triangle to set the
camber accurately. Adjust the front wheels
to 0 degrees of camber (wheel is
perpendicular to the ground). In the rear,
adjust the wheels to 1 to 2 degrees of
negative camber. These adjustments
should0°
be set with the car positioned at its
normal ride height. The following
information gives recommended stock
alignment settings for the Nitro 4-Tec with
-1°TO
stock tires and inserts.
0°
0°
Rear
Camber
-2°
Front Camber Degrees
Rear Camber Degrees
Front Caster Degrees*
Front Toe-In Degrees
-1.0
-1.0
12.0
0.0
* This setting is achieved by having the
1mm caster spacer in the front and the
2mm caster spacer in the rear (where
the upper suspension arm attaches to
the upper suspension arm mount).
It is important that your
engine is properly tuned
and has reached full
operating temperature
before making shift point
adjustments. Stop the
engine before making
adjustments.
The transmission may not
shift if the adjustment screw
is turned too far in (locked
in first gear), or too far out
(locked in second gear). If
the car has quick
acceleration and does not
appear to shift, the
transmission is never
reaching the shift point. The
shift point needs to be
lowered by turning the
adjustment screw counterclockwise. If the car has
poor acceleration but very
high top speed, the
transmission is shifting into
second gear almost
instantly. The shift point
needs to be raised by
turning the adjustment
screw clockwise.
0°
Nitro 4-Tec 3.3 • 33
Adjusting Your Nitro 4-Tec 3.3
At no time should the
body of the car strike the
ground or interfere with
the suspension or tires.
Either situation will
cause extremely
unpredictable handling.
Toe In
Belt Tension Adjustments
Set the steering trim on your transmitter to neutral. Now, adjust your
tie rods so that both wheels are pointing straight ahead and are
parallel to each other (0 degrees toe in). This will ensure the same
amount of steering in both directions. If you run out of adjustment,
then the steering servo will have to be re-centered (see centering your
servos on page 35).
The Nitro 4-Tec’s front and middle drive
belts are designed to have a high initial
tension. During the break-in period, the
drive belts and pulleys will “wear in” and
the belt tension will gradually decrease.
The front and middle belt tensions can be
tightened by inserting shims under the
front bearing block. Do not tighten the
front belt tension unless there is more
than 0.25 inch (6mm) deflection at the
center of the belt (see drawing). To
tighten the belt, add the 0.1mm shim first
and retest. If the belt is still loose, remove
the 0.1mm shim and add the 0.2mm shim
and retest.
Fine Tuning the Shocks
The four shocks on your Nitro 4-Tec have the
most influence on its handling. Whenever you
rebuild your shocks, or make any changes to
the pistons, springs or oil, always do it
carefully and in pairs (front or rear). Piston
head selection depends on the range of oil
viscosities that you have available. For
example, using a one-hole piston with a
lightweight oil will give you the same
dampening as a two-hole piston with heavier
oil. We recommend using the one-hole
pistons with a range of oil viscosities from
10W to 50W (available from your hobby
shop). The thinner viscosity oils (30W or less)
flow more smoothly and are more consistent,
while thicker oils provide more dampening.
Use only 100% pure silicone shock oil to prolong seal life.
The ride height for Nitro 4-Tec can be adjusted by adding or removing
the clip-on spring pre-load spacers. Instead of adding spacers to
increase stiffness, use stiffer springs. Adjust the ride height so that the
suspension arms are slightly above being parallel to the ground. Note
that changes in ride height will occur when the changes in damper
angle or spring rates are made. You can compensate for ride height
changes by changing the pre-load spacers on the dampers. Generally
speaking, ride height should be set as low as possible without causing
significant bottoming of the chassis. Also, in order not to disturb
cornering balance, front and rear tire height diameters should be
equal. Replace excessively worn tires.
34 • Nitro 4-Tec 3.3
Using Belt
Adjustment Shims
The rear belt tension is
adjustable via belt tension
cams in the right and left
rear side plates. The rear
belt in the Nitro 4-Tec
transmits most of the
engine’s power. Because of
Left side plate
Right side plate
the high loading of the rear
(Bulkhead)
(Bulkhead)
belt, the tension should be
Rear of car
Rear of car
checked every 3-4 hours
(20-25 tanks of fuel) of running. If the rear belt can be deflected more
than 0.25¨ (6mm) (see illustration), the belt tension cams should be
rotated rearward to the next eccentric slot.
.25¨ (6mm)
Adjusting Your Nitro 4-Tec 3.3
Gear Ratios
Another Nitro 4-Tec 3.3 feature is the ability to change the gear ratios.
Currently, there are three optional gear ratios for the Nitro 4-Tec. The
stock gear ratio will provide very high (70+ MPH) top speeds. The
following gear ratio chart shows the available combinations with
optional spur gears and clutch bells.
Gear
Clutch
Teeth
Spur
Teeth
Primary
Reduction
Overall
Reduction
Nitro 4-Tec Stock
Equipment
Explosive acceleration
1st
2nd
15
19
45
41
3.00
2.16
5.10
3.67
Optional Clutch Gears
w/Stock Spur Gears
Very good acceleration
1st
2nd
16
20
45
41
2.81
2.05
4.78
3.49
Stock Clutch Gears
w/Optional Spur Gears
Good acceleration
1st
2nd
15
19
41
37
2.73
1.95
4.65
3.31
Optional Clutch Gears
w/Optional Spur Gears
Moderate acceleration
1st
2nd
16
20
41
37
2.56
1.85
4.36
3.15
Nitro 4-Tec gear ratios must be changed as 1st and 2nd gear sets in
order to maintain compatible gear center distances. The gear ratio
chart gives the only four compatible ratio choices.
Changing the Clutch Bell Gears
1. Remove the right, rear wheel. Remove the E-clip
from the two-speed shaft. Slide the pulley and belt off
of the shaft, being careful not to lose the pin that sits
under the pulley. Remove the pin. Slide the spur gears off
of the shaft (If you are using optional gears, you may
have to loosen the right chassis stiffener to remove the
spur gears).
2. Lock the flywheel with a
flathead screwdriver to
immobilize it. Use a 2.5mm
hex wrench to unscrew
the caphead screw that
holds the clutch bell to the
pilot shaft. Remove the
clutch bell.
3. To separate the gears from the clutch
bell, gently grip the clutch bell with
channel-lock, adjustable pliers. Cover
the gears with a cloth to protect the
teeth. Using the pliers, unscrew the
gears counter-clockwise.
4. New clutch gears simply screw onto the clutch bell. Reinstall the
clutch bell and caphead screw onto the pilot shaft. Reinstall the spur
gears, pin, pulley and belt. Secure them on the two-speed shaft with
the E-clip.
5. To adjust the gear mesh, first loosen the four 3x10 countersunk
hex screws in the slotted holes in the bottom of the chassis.
Next, loosen the two countersunk hex head screws in the bottom
of the chassis which hold the slotted engine mount. The engine
should now slide back and forth. Slide a strip of thin note paper
between the spur gears and the clutch bell gears. Push the clutch
bell gears against the spur gears and tighten the screws on the
bottom of the chassis. Remove the paper and the gear mesh is now
correctly adjusted.
Centering the Servos
Whenever your radio system has been removed for service or cleaning,
the servos must be re-centered prior to installing the radio system in
the model. If the radio system is installed in the car, disconnect the
servo horns from the servos.
Connect the steering servo to channel 1 on your receiver and the
throttle servo to channel 2. The white wire on each servo cable is
positioned towards the crystal. Connect the red and black cable from
the battery holder to the “batt” terminal on the receiver. The red wire is
positive and the black wire is negative.
Place fresh “AA” batteries in the transmitter and turn the power switch
on. Slide the throttle and steering trim adjustments to to the center
position. Now install fresh “AA” batteries into the battery holder and
turn the power switch to the on position. The servos will automatically
jump to their center positions.
Turn off the battery holder switch followed by the transmitter. The
servos are now ready to be installed. Be careful not to move the servo
shaft when reinstalling the servo horns.
Nitro 4-Tec 3.3 • 35
Maintaining and Storing Your Nitro 4-Tec 3.3
If the engine is worn or
damaged enough to require
replacing the piston, sleeve,
or connecting rod, consider
exchanging your old engine
for a brand new engine
under the terms of the
Traxxas Lifetime Engine
Replacement Plan (ERP). It
could save you time and
effort. Details are in your
model’s documentation
package or on our website.
The TRX 3.3 is designed to
be easy to rebuild. Critical
engine components such as
the crankcase, crankshaft,
and engine bearings are
made to extremely high
quality standards and
should under normal
circumstances outlast
multiple sets of pistons,
sleeves, connecting rods,
and wrist pins (reciprocating
assemblies). It could be
more economical for you to
continue to use your good
bearings and crankshafts,
and simply replace the
reciprocating assembly as
needed. Engine assembly is
not difficult and replacing
the reciprocating assembly
does not require any special
tools or skills.
36 • Nitro 4-Tec 3.3
Your Nitro 4-Tec requires timely maintenance in order to stay in top
running condition. Neglecting the maintenance could allow dirt,
deposits, and moisture to build up inside the engine leading to internal
engine failure. The following procedures should be taken very seriously.
After each hour of running:
Clean and re-oil the air filter. The instructions for this procedure are on
page 22. We cannot stress enough the value of cleaning your air
filter at the scheduled intervals. The cleanliness and condition of your
air filter directly influences the running life span of your engine. Do not
skip air filter maintenance!
Clean the outside of the engine of accumulated dirt, oil, and grime.
Accumulated grime will decrease the engine’s ability to cool itself.
To maintain optimum radio system performance, the RX Power Pack
(receiver battery) should be recharged after each hour of runtime.
Tighten the wheel nuts (especially on the left side). Use the 8mm end
of the included glow plug wrench.
After each running session:
Perform after-run maintenance on the engine. This clears the engine
of destructive moisture and other corrosive deposits. This is extremely
important for the life of the engine. Read on for after-run
maintenance procedures.
Inspect the gears for wear, broken teeth, or debris lodged
between the teeth
Inspect the vehicle for obvious damage or wear. Look for:
1.
2.
3.
4.
5.
Loose or missing screws
Cracked, bent, or damaged parts
Cut or loose wiring
Cut or kinked fuel lines
Signs of fuel leakage
Other periodic maintenance:
Connecting rod: The connecting rod should be replaced when the
piston and sleeve are replaced. Also replace the piston wrist pin and
G-clip whenever the connecting rod is replaced. As with other
internal engine components, connecting rod life depends engine’s
usage and the quality and frequency of the engine maintenance.
Inspect the connecting rod after 3-gallons of fuel have been used.
Piston/sleeve: The life of the piston and sleeve will
vary greatly with how the engine was used and
maintained. The piston and sleeve should be
replaced when they no longer seal effectively (loss
of compression). Symptoms include the engine
being difficult to start when warm, stalling when
warm, and stalling when throttle is suddenly closed
to idle. Replace the wrist pin and G-clip whenever
the piston and sleeve are replaced.
After-run Procedure
You must perform after-run maintenance on your Traxxas
engine whenever the model will be stored for longer
than a few hours. Taking the time to prepare your engine
for storage will reward you with longer engine life, easier
starting, and better performance.
When a nitro engine is shut off, some excess unburned
fuel remains in the engine. The methanol in model
engine fuel is hygroscopic, which means it easily attracts and absorbs
moisture. This moisture can cause rust and corrosion on the steel engine
parts (crankshaft, bearings, wrist pin and starter shaft) if the fuel is not
removed from the engine. There are after run oil products available from
your hobby dealer or you can use WD-40™,
a common household lubricant. To ensure your TRX 3.3 Racing Engine is
protected from internal corrosion, use the following procedure:
1. Whenever possible, shut off the engine by pinching the fuel line
closed. This allows most of the excess fuel to be consumed by the
engine. Be sure the throttle is in the idle position. You may have to
pinch the fuel line closed for several seconds before the engine stops.
2. Completely empty the fuel tank. Use your fuel-dispensing bottle to
suck out the old fuel. Do not mix the old fuel with your fresh fuel
supply. If you leave fuel in the tank, transporting or handling your
Nitro 4-Tec may cause fuel to run into the engine.
3. With the fuel tank empty and the throttle at the idle position, try to
start the engine. The engine will most likely start and run for a few
seconds as it uses up any fuel remaining in the engine and fuel lines.
4. Once the engine stops, clean the outside of the engine with
compressed air or spray motor cleaner. Once the engine is clean and
dry, remove the glow plug power wire, glow plug, and air filter.
Maintaining and Storing Your Nitro 4-Tec 3.3
5. Open the throttle fully and spray a one-second burst of WD-40 into the
carburetor and into the glow plug hole (Caution! Wear safety glasses to
prevent spray from getting into your eyes). If you are using after-run
oil, follow the manufacturer’s instructions.
6. Place a rag or paper towel over the engine to catch any WD-40 or afterrun oil that may come out the carburetor or glow plug hole.
7. Connect the EZ-Start controller to the model and spin the engine for
10 seconds.
8. Remove the rag or paper towel and repeat steps 5–7 two more times.
9. Clean and re-oil the air filter so it will be ready for use next time. See
page 22 for air filter maintenance instructions.
10. Replace the glow plug, reconnect the glow plug power wire, and
reinstall the air filter.
Clearing a Flooded Engine
If the engine is primed for too long during startup, then it can become
flooded with fuel. When the engine is flooded it will no longer turn due to
excess fuel in the combustion chamber preventing upward movement of
the piston. Use the following procedure to clear a flooded engine:
1. Remove the blue glow plug wire.
2. Remove the glow plug and gasket with the glow plug wrench supplied
with your model. A 5/16 or 8mm nut driver will also work.
3. Turn the model upside down and plug in the EZ-Start controller.
4. Push the EZ-Start button for several seconds to clear the engine
of excess fuel. Do not look into the glow plug hole while the
engine is spinning or you could spray fuel into your face!
5. Turn the model over and reinstall the glow plug and gasket.
6. Reconnect the blue glow plug wire to the glow plug.
Piston stuck at “top dead center” (TDC)
“Top dead center” is the position where the piston is
at the very top of the tapered sleeve. Occasionally an
engine can get “stuck” at this position. This is most
likely to happen on new engines during break-in, but
can also happen at other times. If the engine is stuck
at TDC, use the following procedure to release the
piston from the sleeve:
Top Dead Center
1. Remove the glow plug using the included tool or
8mm (5/16") nut driver and verify that the piston
is at the top of its stroke.
2. Turn the Nitro 4-Tec over and locate the flywheel
through the cutout in the chassis. Insert a flat blade
screwdriver as shown between the chassis and
flywheel. Using the chassis for leverage, rotate the
flywheel counterclockwise by pressing down on
the screwdriver. The flywheel will turn, unsticking
the piston from the sleeve.
3. Put two or three drops of light machine oil into
the glow plug hole to lubricate the piston and
sleeve. Do not use too much oil. It will hydro-lock
the engine. Verify the starter will spin the engine
with the glow plug out.
4. Rotate the flywheel so the piston is at bottom
Bottom Dead Center
dead center and replace the glow plug with gasket.
Reconnect the blue glow plug wire.
5. You should now be able to start the engine with the EZ-Start.
Denatured alcohol
(available from home
centers and paint supply
stores) in a spray bottle is
an extremely effective
cleaner. Be sure to wear
safety glasses and gloves
when working with
denatured alcohol.
Be sure to follow proper
maintenance and storage
procedures to avoid
damage to your engine
and other components of
your Nitro 4-Tec.
Don’t put the fuel from
your tank back into your
fuel jug. Dispose of it
properly, following city or
county regulations.
Always wear eye
protection when using
compressed air or spray
cleaners and lubricants.
7. Reconnect the EZ-Start controller.
8. Do not prime the engine. Pull the throttle to 1/2 throttle and push the
EZ-Start button. The engine should start immediately.
Nitro 4-Tec 3.3 • 37
Troubleshooting Your Nitro 4-Tec 3.3
The following section addresses some very basic engine and radio
questions you may have about your Nitro 4-Tec 3.3. Most questions arise
from simple user errors or minor adjustments that are easy to correct.
If you can’t find a solution for your Nitro 4-Tec here, then visit our Web
site at www.Traxxas.com and click on the Customer Support menu.
There you will find a much more extensive and detailed online
troubleshooting area. In addition, you may call Traxxas Customer
Service at 1-888-TRAXXAS (outside the US call 972-265-8000).
Radio system does not work properly:
If the power light on the transmitter does not come on, check for
proper battery installation and that the batteries are new and/or fully
charged. If the power light is blinking, then the transmitter batteries
are weak and should be replaced. See page 11 for more details.
If the transmitter light is on but the radio is still not responding,
check for proper installation of the receiver batteries and that the
batteries are new and/or fully charged. Check to make sure the
on/off switch on the model is in the on position. Finally, if there is
still no response check the red and black wires that connect the
battery pack to the “batt” terminal on the receiver (you will have to
remove the receiver cover). Make sure the wires are not pinched or
damaged and that the plug is secure in the receiver. See page 13 for
more details.
Short radio range:
If the radio range appears short, then first check to make sure the
transmitter antenna is fully extended and that the antenna in the
Nitro 4-Tec is in place and has not been cut or damaged. Next, make
sure the batteries are all fully charged. Finally, if you are still
experiencing short range, try a different location. Sometimes there
can be interference from various sources that can cause your radio to
malfunction.
Engine will not spin (EZ-Start will not turn the engine):
If neither LED on the controller lights, the EZ-Start battery could be
discharged or improperly connected. Inspect and recharge if
necessary.
38 • Nitro 4-Tec 3.3
If the glow plug LED lights and the motor LED does not, then the EZStart controller is in protection mode. Allow the controller to cool for
at least three minutes. The circuitry should automatically reset.
Check to make sure the wires are connected to the EZ-Start motor in
the Nitro 4-Tec. The red wire should connect to the positive motor
terminal, indicated by a red dot next to the terminal.
The engine could be flooded. If too much fuel accumulates in the
combustion chamber at start up, the engine will hydraulically lock.
Follow the procedure on page 37 for clearing a flooded engine.
Check for binding at the engine flywheel. If you are not able to turn
the engine by hand, the engine could be flooded, there could be
binding in the clutch system, or there could be internal engine
damage. See page 37 for info on clearing a flooded engine and
releasing a stuck piston. (Note: It is normal for the engine to be
extremely tight and hard to turn when the piston reaches the top of
the compression stroke.)
Engine extremely sluggish, hard to start, and will not idle
during tank 1 of the break in:
It is possible that the factory adjusted break-in settings on your
carburetor are too rich for your geographic location, atmospheric
conditions, or fuel brand. Extremes in temperature, humidity,
barometric pressure, and altitude can’t always be accounted for with
a single high-speed needle setting. The symptoms described above
can occur when the air density is very low such as in high
mountainous elevations, and extremely cold temperatures. Under
these conditions, lean the fuel mixture slightly, 1/8 turn, to see if
there is any improvement in starting and idling. Only lean the fuel
mixture just until the engine will run and idle reliably and then
proceed with the break in.
The contents of different brands of fuel (other than Traxxas Top Fuel)
in combination with extreme atmospheric conditions can also make
the factory preset break-in settings too rich and cause the symptoms
described above. Again, try leaning the fuel mixture slightly, 1/8 turn,
to see if there is any improvement in starting and idling.
Troubleshooting Your Nitro 4-Tec 3.3
Engine spins but will not start:
If the engine is spinning but will not start, first check to make sure
that both the motor and glow plug LEDs on the EZ-Start controller
light when the button is depressed. If the glow plug LED does not
light, make sure the blue glow plug wire is tightly connected and is
not damaged in any way. If the wire is good, then replace the glow
plug. It is normal for glow plugs to require periodic replacement. Only
use Traxxas heavy-duty long glow plugs (part #3231).
Check to make sure the fuel is getting to the carburetor. Remove the
fuel line where it connects to the carburetor to see if there is fuel in it.
If not, you may need to prime the engine. Reconnect the fuel line and
then refer to page 27 for instructions on priming the engine.
Try a new Traxxas 3231 glow plug. Sometimes a glow plug will work
well enough to start the engine but not be able to deliver the
engine’s full performance potential.
If the fuel mixture seems to be set correctly, make sure the fuel is
fresh. If the fuel is old, or was left uncapped for a long period, then
some of the important fuel components could have evaporated. Try
new, fresh, Traxxas Top Fuel
Check to make sure there is no binding in the driveline that would
cause excessive loads on the engine.
Check your fuel mixture settings. It may be necessary to adjust the
fuel mixture if the outside temperature or barometric pressure has
changed significantly since the last time the engine was run (see Fine
Tuning the Carburetor on page 31). Turn the high-speed needle out
(rich/counterclockwise) 1/4 turn, hold the throttle trigger at about 1/2
throttle and try again to start the engine. Once started, retune the
engine for performance (see page 29).
The engine could be worn. If the fit between the piston and sleeve is
loose, compression is reduced and the engine will be difficult to start
when it is warm, and may tend to stall when running and when the
throttle is closed suddenly to idle. Engine life depends on many
factors including fuel type, air filter maintenance, needle settings, and
how the engine was used. For example, if the engine was allowed to
ingest dirt from lack of air filter maintenance or running through
water, then the internal engine components could wear out
extremely fast.
Engine performance sluggish:
Engine performance depends mostly on the fuel mixture settings and
how they compensate for the current atmospheric conditions. Before
you suspect other failures with the engine, richen the high-speed
needle at least 1/4 turn and then retune the engine for performance
(see page 29).
Nitro 4-Tec 3.3 • 39
Index
ABC, 19
Adjustments, 33
After-run procedure, 36
Air density, 30
Air filter, 6, 18, 19, 22
cleaning, 22
foam, 19
Air intake, 18
Air/fuel mixture, 23
Air/fuel ratio, 23
Alignment, 33
Altitude, 28
Ambient temperature, 31
Antenna (receiver), 9, 13
mount, 6
Antenna (transmitter), 9
Atmospheric conditions, 23, 31
Barometric pressure, 31
Baseline setting, 31
Batteries, 11
alkaline, 5
charging, 11, 25
compartment, 9, 11
installing, 12
NiCad (nickel-cadmium), 10, 11
NiMH (nickel-metal hydride), 10, 11
receiver, 12
rechargeable, 12
transmitter, 11
Battery Holder, 6
BDC (Bottom Dead Center), 19, 37
Bearing Block, 6
Bellcrank, 6
Body Mount, 6
installing, 8
Break-in, 19, 27
starting, 27
40 • Nitro 4-Tec 3.3
Tank 1, 28
Tank 2, 28
Tank 3, 28
Tank 4, 28
Tank 5, 28
Tank 6, 28
winter, 29
Bumper Plate, 6
Camber, 33
Camber Link (Turnbuckle), 6
Carburetor (carb), 18, 19, 23
adjustments, 23
fine-tuning, 31
slide carburetor, 20
venturi, 23
Chassis, 6
Clean-out, 19
Clutch bell, 18
changing, 35
Combustion chamber, 19
Connecting rod, 19
maintenance, 36
Cooling fins, 19
Crankcase, 18, 19
Crankshaft, 18, 19
Customer service, 3
Cylinder sealing, 27
Decals, 8
Differential, 6
Drive Belt, 6
adjustment shims, 34
pulley, 6
tension adjustments, 34
Driving, 32
Dyno, 19
E-mail, 3
Engine (TRX 3.3), 6
clearing a flood, 37
cutting out, 29
detonation, 30
hesitation, 30
high altitude operation, 28
lubrication, 21, 24, 31
overheating, 29, 30
priming, 20, 27
shut-off clamp, 18, 26
sluggish, 28, 30
stalling, 27, 30, 36
starting, 26, 27
temperature, 27, 29, 31
terms, 19
tuning, 29
tuning by temperature, 31
EZ-Start, 18, 19, 25
battery, 26
installing, 25
controller, 18
drive unit, 18
Glow Plug LED, 26
motor, 6, 18
Motor LED, 26
plug, 6, 18
glow plug wire, 18
ground wire, 18
negative wire, 18
positive wire, 18
protection mode, 26
using, 26
Fit, 19
Flame-out, 19
Flywheel, 18
Foam Bumper, 6, 8
Frequency, 10
clearing, 10
Index
Fuel (Top Fuel), 5, 19, 21, 37
break-in, 27
dispensing bottle, 5
flow, 21, 23
handling, 21
other fuels, 21
unburned, 26, 36
Fuel intake, 18
Fuel line (fuel tubing), 6, 18, 19
Fuel mixture, 19, 23
Fuel tank, 6, 18
filling, 22
fuel tank lid, 6
Gear Ratios, 35
Glow plug, 19
driver, 20
glow plug wire, 18
Head (cylinder head), 18, 19
Head protector, 18
Header, 6, 18, 20
High-speed needle, 18, 20
adjustment, 30
Humidity, 30
Idle speed screw, 18, 20, 24
adjustment, 31
Lean, 20
leaning the mixture, 20
maximum safe lean setting, 30
Low-speed needle, 18, 20
adjustment, 30
mAh, 10
Maintenance, 36
Needle Settings, 24
Needle valve, 20
Nitromethane (Nitro), 20
content, 20
percentage, 21
O-ring, 20
On/Off Switch, 6
Pinch test, 30
Pipe, 6, 18, 20
hanger, 6
Piston, 20
maintenance, 36
stuck at “top dead center”, 37
Port, 20
Pressure line, 6, 18
Punch, 20
Quick Start, 7, 8, 11, 12, 13, 16, 17, 22, 26, 27, 28,
30, 33, 40
Radio system (TQ), 9
channel, 10
controls, 14
crystal, 10
range-testing, 16
rules, 15
terminology, 10
trim, 10
using, 16
Range, 13
Receiver, 6, 9, 10, 15
Rich, 20
rpm, 20
Safety, 4, 37
Servo chart, 14
Servo reversing switches, 9
Servo, steering, 6
Servo, throttle/brake, 6
Servos, centering the, 35
Shift Point, 33
Shipping, 3
Shock Tower, 6
Shocks (Oil Dampers), 6
fine tuning, 34
Sleeve, 20
maintenance, 36
Smoke, 29
Stall, 20
Steering trim, 9
Steering wheel, 9
Supplies, 5
Support, 3
Suspension Arm, 6
TDC (Top Dead Center), 20, 37
Temperature gauge, 31
Throttle arm, 18
Throttle neutral adjust, 9
Throttle trigger, 9
Throttle trim, 9, 16
Tie Rod (Turnbuckle), 6
Tires, 6
Toe In, 34
Tools, 5
Transmission, 6
Transmitter, 9, 10, 11, 14, 15
power indicator, 9, 11
power switch, 9
Troubleshooting, 38
Turn, 23
Wear-in, 20
Weather conditions, 31
Wiring Diagram, 9
WOT, 20
Nitro 4-Tec 3.3 • 41
Notes
42 • Nitro 4-Tec 3.3
Notes
Nitro 4-Tec 3.3 • 43
owners manual
MODEL 4809
060602
1100 Klein Road, Plano Texas 75074
1-888-TRAXXAS