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Once you become familiar with driving your Nitro 4-Tec, you may
wish to make adjustments for better driving performance.

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 allen 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
through the access hole. Note
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 allen 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

counter-clockwise 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.

7.

Use 1/8 turn increments to find the approximate, desired shift
point.

8.

Check performance by running a test lap after each
adjustment.

9.

Use 1/8-1/16 turn increments to fine tune the shift point.

Alignment Specs

The Nitro 4-Tec is supplied with soft-compound, race-quality
tires. Due to the high power output of the TRX 2.5 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 rear wheels can be
adjusted with the 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 should 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 stock
tires and inserts.

• Front Camber Degrees  ......-1.0
• Rear Camber Degrees  ........-1.0
• Front Caster Degrees* ........12.0
• Front Toe-In Degrees  ............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).

38

Adjusting Your Nitro 4-Tec

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 counter-
clockwise. 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.  

Access

Hole

Drum

-1

°

-2

°

TO

0

°

Front
Camber

Rear
Camber

Summary of Contents for 4810

Page 1: ...Nitro 4 Tec Owner s Manual Model 4810 ...

Page 2: ...s com Entire contents 2003 Traxxas Corporation Traxxas Nitro 4 Tec TRX 2 5 TQ Top Fuel EZ Start Ready To Race and ProGraphix are trademarks or registered trademarks of Traxxas Corporation 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 witho...

Page 3: ...ctric starting The new second generation EZ Start has evolved into an incredibly advanced and reliable starting solution featuring thermal protection for the motor and built in diagnostics to monitor the condition of the glow plug In this manual we ll take you step by step through all necessary set up break in tuning and operating procedures Even if you are an experienced R C enthusiast it is impo...

Page 4: ...nal safety or avoiding damage to your Nitro 4 Tec and related components Special advice from Traxxas to make things easier and more fun Refers you to a page with a related topic Support If you have any questions about your Nitro 4 Tec 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 30 am ...

Page 5: ... refueling or stopping the engine 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 Don t 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 ...

Page 6: ...lt NiCad battery pack for the EZ Start starting system NiCad battery charger Traxxas Top Fuel 10 quart 5010 20 quart 5020 10 gallon 5060 20 gallon 5070 Fuel dispensing bottle Traxxas part 5001 TRAXXAS 1 5mm hex wrench 2 0mm hex wrench Glow plug universal wrench Turnbuckle wrenches Batteries Fuel Supplied Tools Your Nitro 4 Tec comes with these specialty metric tools Other Required Tools and Suppli...

Page 7: ...g Block Air Filter Pipe Header Engine see pg 21 for details Pressure Line Fuel Line EZ Start Motor EZ Start Plug Shock Tower Body Foam Bumper Mount Chassis lower 7 On Off Switch Antenna Mount Pipe Hanger Front Camber Link Turnbuckle Racing Tires Two Speed Transmission Bellcrank Steering Front Differential Front Drive Belt Drive Belt Pulley Rear Differential Body Mount Center Drive Belt ...

Page 8: ...o system See page 18 Make a habit of turning the transmitter on first and off last 10 Check servo operation See page 19 Make sure the throttle and steering servos are working correctly 11 Range test the radio system See page 20 Follow this procedure to make sure your radio system works properly at a distance and that there is no interference from outside sources 12 Fill the fuel tank See page 26 U...

Page 9: ...d carefully pull it off the body in one continuous piece Your Nitro 4 Tec decals are die cut for easy removal Use a hobby knife to lift the corner of a decal and lift it from the backing 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 Look at the photos on the ...

Page 10: ...ews Now 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 The rear body mounts attach as shown in the drawing 10 Installing Nitro 4 Tec Body Mounts 3x10mm Countersunk Self tapping screws Foam Bumper 3x14mm Washerhead Self tapping screws Installing Rear Body Mounts Installing Front Body Mounts ...

Page 11: ...c makes use of two channels for throttle brake and steering Nitro 4 Tec Wiring Diagram Antenna On Off Switch Black Negative Red Positive Receiver 4 Cell Battery Holder Channel 1 Steering Servo Channel 2 Throttle Servo Channel 2 Channel 1 Battery CH 2 CH 1 Antenna Throttle Neutral Adjust Steering Wheel Throttle Trim Steering Trim Power Switch Power Indicator Battery Compartment Servo Reversing Swit...

Page 12: ...TR models operate on a 27 MHz frequency band Neutral position The standing position that the servos seek when the transmitter controls are at the neutral setting NiCad Refers to rechargeable nickel cadmium batteries The most economical choice since they may be recharged up to 500 times Receiver The radio unit inside your Nitro 4 Tec that receives signals from the transmitter and relays them to the...

Page 13: ...s The power indicator light does not indicate the charge level of the receiver batteries in the model Use the Right Batteries Your transmitter and receiver use AA batteries Use new alkaline batteries or rechargeable batteries such as NiCad or Ni MH nickel metal hydride batteries in your transmitter and receiver Make sure rechargeable batteries are fully charged according to the manufacturer s inst...

Page 14: ...re 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 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 incl...

Page 15: ... the black antenna wire that exits the receiver The Nitro 4 Tec receiver is mounted on the side of the upper chassis The receiver is wrapped in a balloon for protection The color of the balloon indicates the channel number see page 12 2 Pull the wire straight with your fingers and then insert the end of the wire into one end of the antenna tube Push the wire all the way through the antenna tube 3 ...

Page 16: ...by pressing the button and sliding it to the desired position There are two settings available 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 the Nitro 4 Tec with the TRX 2 5 Racing Engine Electronic Throttle Trim The electronic throttle trim located on the face of the transmitter adjusts t...

Page 17: ...he model drive straight with no steering input at the wheel Servo Reversing Switches 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 ...

Page 18: ... and running out of control 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 Always use new or freshly charged batteries for the radio system Weak batteries will limit the range of the radio signal between the re...

Page 19: ... 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 6 Operate the throttle trigger on the transmitter and check for rapid operation of the throttle serv...

Page 20: ... 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 5 Do not attempt to operate the model if there is any problem with the radio system or any external interference with your ...

Page 21: ...l 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 2 5 racing engine Old style break in procedures such as 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 steps in this manual A routine maintenance ...

Page 22: ...Start Motor Low Speed Needle Throttle Arm Clutch Bell Flywheel Carburetor Air Intake Fuel Intake High Speed Needle Idle Speed Screw EZ Start Plug Positive Wire Negative Wire Fuel Line Fuel Tank Pipe Exhaust Tip Pressure Line Ground Wire Glow Plug Wire EZ Start Controller 22 Crankshaft Crankcase Header Pipe Coupler ...

Page 23: ...here 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 2 5 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 Cooling fins The c...

Page 24: ...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 ne...

Page 25: ...ternal 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...

Page 26: ... or a claim to make about fuel The engineering team at Traxxas spent over 2 years developing the TRX 2 5 racing engine 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 2 5 Handling the Fuel Follow all directions and warnings on the fuel can ...

Page 27: ...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 by saturating it with foam filter oil Use the supplied Traxxas filter oil part 5263...

Page 28: ... 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 The Fuel Mixture Needles The amount of fuel metered and atomized by the carburetor is controlled by the two mixture needles th...

Page 29: ...s 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 The Idle Speed Adjus...

Page 30: ...t NiCad 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 NiCad battery pack into the connector inside 3 Twist the battery 2 or 3 times to twirl the battery plug wires This helps hold the wire...

Page 31: ...oad 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 ca...

Page 32: ...f fuel As the engine begins to break in the duration and intensity of the acceleration will gradually increase Sustained high speed running is not permitted until the 6th tank of fuel Perform the initial break in on a large flat paved surface Apply all throttle and braking actions gently Abrupt acceleration or braking could cause the engine to stall unnecessarily Special break in fuels are not rec...

Page 33: ...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 2 As the engine loosens the idle speed may increase ...

Page 34: ...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 Before you begin t...

Page 35: ...still maintaining reliable running characteristics 4 Reset the throttle trim on the transmitter Fine Tuning the Carburetor After fine tuning your TRX 2 5 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 c...

Page 36: ... degree weather For this reason we cannot give you a definitive temperature range that indicates the best possible engine tuning The temperature gauge can aid you in tuning by giving you a relative indication of how your adjustments are affecting the engine and by preventing you from exceeding maximum engine temperature For example as you lean the fuel mixture the engine performance will increase ...

Page 37: ...elies 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 da...

Page 38: ...RX 2 5 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 rear wheels can be adjusted with the camber rods upper turnbuckles Use a square or right angle triangle to set the camber a...

Page 39: ...tes 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 Belt Tension Adjustments The Nitro 4 Tec s front...

Page 40: ...iers 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 remove the two...

Page 41: ...ack 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 automatic...

Page 42: ...y connected Inspect and recharge if necessary If the glow plug LED lights and the motor LED does not then the EZ Start 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 indicate...

Page 43: ...k 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 caus...

Page 44: ... closed to idle Replace the wrist pin and G clip whenever the piston and sleeve are replaced Connecting rod The connecting rod should be replaced when the piston and sleeve are replaced or after three gallons of fuel whichever comes first 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 ...

Page 45: ... 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 5 Open the throttle fully and spray a one second burst of WD 40 into the carburetor and into...

Page 46: ...amber 23 Compression 24 43 44 Connecting rod 23 44 Cooling fins 23 Crankcase 22 23 Crankshaft 22 23 45 Crystal 12 18 Customer service 4 42 43 Cylinder sealing 32 Decals 9 Drive Belt 7 39 tension 39 Drivetrain friction 37 Dyno 23 E mail 4 Engine TRX 2 5 7 22 26 cutting out 34 break in 21 23 32 driving procedure 33 cooling 36 44 damage 27 detonation 34 failure 27 44 flooding 31 42 43 hesitation 34 l...

Page 47: ...ence 5 20 Radio System 11 12 19 42 43 adjustments 16 controls 16 range testing 20 rules 18 terminology 12 terms 12 Range 14 15 18 20 42 43 short 42 43 Receiver 11 12 42 cover box 7 42 43 Required equipment 6 Rich 25 29 RPM 25 limits 37 Safety 5 Servo reversing switches 11 16 Servos 7 11 12 41 centering 41 reversing 11 17 steering 7 11 17 19 throttle brake 7 11 16 17 19 Shift point 38 Shipping 4 Sh...

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