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Thank you for purchasing the new T-Maxx 3.3. This T-Maxx is our biggest and meanest Maxx ever, and we are confident it will reward you with many hours of exciting monster truck action.
We know you're excited about getting your new T-Maxx 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 T-Maxx 3.3. Even if you are an experienced R/C enthusiast, it's important to read and follow the procedures in this manual. T-Maxx 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.
T-Maxx 3.3 is made to be a complete package that starts with the highest level of engineering and is equipped stock with the most powerful Ready-To-Race® engine available. We want you to feel confident that you own the best-performing truck in the market and that it is backed by a team of professionals who aim to provide the highest level of factory support possible. T-Maxx 3.3 is about experiencing total performance and satisfaction, not just with your truck, 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 T-Maxx 3.3!
Carefully read and follow all instructions in this and any accompanying materials to prevent serious damage to your T-Maxx 3.3. Failure to follow these instructions will be considered abuse and/or neglect.
Traxxas Support
Traxxas support is with you every step of the way. Refer below 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 outlines 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.
Before running your T-Maxx 3.3, look over this entire manual and examine the truck carefully. If for some reason you decide the T-Maxx 3.3 is not what you wanted, then do not continue any further. Your hobby dealer absolutely cannot accept a T-Maxx 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 model and related components.
Special advice from Traxxas to make things easier and more fun.
SUPPORT
If you have any questions about your T-Maxx 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 8:30 am to 9:00 pm 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 hundreds of Traxxas R/C enthusiasts in our online community at www.Traxxas.com.
Traxxas offers a full-service, on-site repair facility to handle any of your Traxxas service needs. Maintenance, replacement parts, and accessories 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. Do not hesitate to contact us with any of your product support needs. We want you to be thoroughly satisfied with your new T-Maxx 3.3!
REGISTERING YOUR MODEL
In order to serve you better as our customer, please register your product within 10 days of your purchase online at Traxxas.com/register.
All of us at Traxxas want you to safely enjoy your new T-Maxx 3.3. Operate your T-Maxx 3.3 sensibly and with care, and it will be exciting, safe, and fun for you and those around you. Failure to operate your T-Maxx 3.3 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
Children (minors) under 16 years of age and inexperienced drivers should not operate the T-Maxx 3.3 without the supervision of a responsible and knowledgeable (experienced) adult.
Batteries and Battery Charging
Your model uses rechargeable batteries that must be handled with care for safety and long battery life. Make sure to read and follow all instructions and precautions that were provided with the battery packs and your charger. It is your responsibility to charge and care for the battery packs properly. In addition to your battery and charger instructions, here are some more tips to keep in mind.
Recycling Your Traxxas Power Cell NiMH Battery
Traxxas strongly encourages you to recycle your Power Cell NiMH battery when it has reached the end of its useful life. Do not throw your battery in the trash. All Power Cell NiMH battery packs display the RBRC (Rechargeable Battery Recycling Corporation) icon, indicating they are recyclable. To find a recycling center near you, ask your local hobby dealer or visit www.call2recycle.org.
T-Maxx 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
REQUIRED TOOLS AND EQUIPMENT (sold separately)
ACCESSORY EQUIPMENT (sold separately)
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:
Tire Gluing
The factory tires on your T-Maxx 3.3 are already glued to the rims. The tires must be glued to the rims to prevent the rims from spinning inside the tires. The instructions here are provided to show you how to glue replacement tires to the rims in the future. Use CA tire glue, such as Traxxas Ultra Premium Tire Glue (part #6468). You can glue the tires without removing the wheels from the truck. For clarity, these instructions show the process with the wheels removed.
Applying the Decals
The main decals have already been applied to your T-Maxx 3.3. 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. 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 box for typical decal placement.
Your model includes the latest Traxxas TQi 2.4GHz transmitter with Traxxas Link ™ Model Memory. The transmitter's easy-to-use design provides instant driving fun for new R/C enthusiasts, and also offers a full compliment of pro-level tuning features for advanced users – or anyone interested in experimenting with the performance of their model. The steering and throttle channels feature adjustable Exponential, End Points, and Sub- Trims. Steering and braking Dual Rate are also available. Many of the next-level features are controlled by the Multi-Function knob, which can be programmed to control a variety of functions. The detailed instructions included in this manual will help you understand and operate the advanced functions of the new TQi radio system. For additional information and how-to videos, visit Traxxas.com.
Please take a moment to familiarize yourself with these radio and power system terms. They will be used throughout this manual.
2.4GHz Spread Spectrum – This model is equipped with the latest R/C technology. Unlike AM and FM systems that require frequency crystals and are prone to frequency conflicts, the TQi system automatically selects and locks onto an open frequency, and offers superior resistance to interference and "glitching."
Current - Current is a measure of power flow through the electronics, usually measured in amps. If you think of a wire as a garden hose, current is a measure of how much water is flowing through the hose.
Frequency band - The radio frequency used by the transmitter to send signals to your model. This model operates on the 2.4GHz directsequence spread spectrum.
mAh – Abbreviation for milliamp hour. A 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.
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 model that receives signals from the transmitter and relays them to the servos.
Servo - Small motor units in your model that operates the steering and throttle mechanisms.
Transmitter - The hand-held radio unit that sends throttle and steering instructions to your model.
Trim - The fine-tuning adjustment of the neutral position of the servos, made by adjusting the throttle and steering trim knobs on the face of the transmitter.
Note: The Multi Function knob must be programmed to serve as a throttle trim adjustment.
3-channel radio system - The TQi radio system, consisting of the receiver, the transmitter, and the servos. The system uses three channels: one to operate the throttle, one to operate the steering and an optional third channel.
Your TQi transmitter uses 4 AA batteries. The battery compartment is located in the base of the transmitter.
If the status LED flashes red, the transmitter batteries may be 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 battery pack installed in the model.
Use the Right Batteries
Your transmitter uses AA batteries. Use new alkaline batteries. Do not use rechargeable AA cells to power the TQi transmitter, as they will not provide sufficient voltage for optimum transmitter performance.
Discontinue running your model at the first sign of weak batteries (flashing red light on the transmitter) to avoid losing control.
The radio receiver in your model uses 4 AA batteries. The receiver battery holder is located underneath the battery cover. The battery cover can be identified by the on/off switch.
If the radio system doesn't appear to work when the transmitter and receiver switches are turned on, check for correct battery installation.
Optional Accessory: Rechargeable Receiver Battery
Your model can be upgraded with the RX Power Pack NiMH rechargeable receiver battery (part #3037). This battery eliminates the 4-cell battery holder and the need to replace alkaline batteries.
Automatic Fail-Safe
The TQi transmitter and receiver are equipped with an automatic fail-safe system that does not require user programming. In the event of signal loss or interference, the throttle will return to neutral and the steering will hold its last commanded position. If Fail-Safe activates while you are operating your model, determine the reason for signal loss and resolve the problem before operating your model again.
Steering Trim
The electronic steering trim located on the face of the transmitter adjusts the neutral (center) point of the steering channel.
Note: Traxxas Stability Management (TSM) must be completely turned off while adjusting steering trim.
Multi-Function Knob
The Multi-Function knob can be programmed to control a variety of functions. From the factory, the Multi-Function knob controls Traxxas Stability Management (TSM).
The TQi Radio System has been pre-adjusted at the factory. The adjustment should be checked before running the model, in case of movement during shipping. Here's how:
Remember, always turn the TQi transmitter on first and off last to avoid damage to your T-Maxx 3.3. Never turn the radio off while the engine is running.
Range-Testing the Radio System
Before each running session with your model, you should range-test your radio system to ensure that it operates properly.
Higher Speeds Require Greater Distance
The faster you drive your model, the more quickly it will near the limit of radio range. At 60mph, a model can cover 88 feet every second! It's a thrill, but use caution to keep your model in range. If you want to see your model achieve its maximum speed, it is best to position yourself in the middle of the truck's running area, not the far end, so you drive the truck towards and past your position. In addition to maximizing the radio's range, this technique will keep your model closer to you, making it easier to see and control.
No matter how fast you drive your model, always leave adequate space between you, the model, and others. Never drive directly toward yourself or others.
TQi Binding Instructions
For proper operation, the transmitter and receiver must be electronically 'bound.' This has been done for you at the factory. Should you ever need to re-bind the system or bind to an additional transmitter or receiver, follow these instructions. Note: the receiver must be connected to a 4.8-6.0v (nominal) power source for binding and the transmitter and receiver must be within 5 feet of each other.
Traxxas Stability Management or TSM allows you to experience all the speed and acceleration that was engineered into your Traxxas model by helping you to maintain control of the vehicle in low-traction situations. TSM helps provide straight ahead full-throttle acceleration on slippery surfaces, without fishtailing, spinouts, or loss of control. TSM also dramatically improves braking control. High speed cornering and control is also made possible as TSM makes corrections for you, without intruding on your fun, or creating unexpected side effects.
The Multi-Function knob on the TQi transmitter has been programmed to control TSM. The recommended (default) setting for TSM is to rotate the knob to the 12:00 position (the zero mark on the dial).
Turn the knob clockwise to increase assistance; turn the knob counterclockwise to decrease assistance. Turn the knob counterclockwise to its stop to turn TSM completely off.
Note: TSM is deactivated automatically when driving or braking in reverse.
When driving on surfaces with some traction, decrease the TSM setting to allow the vehicle to feel more "loose" for power sliding, drifting, and so on. On surfaces with very little traction (loose dirt, smooth concrete, ice/snow), increase TSM to maximize acceleration and control.
Drive with TSM on and off to test how it is making your control of the vehicle easier and more precise. For more information, visit Traxxas.com/tsm.
Note: TSM must be completely turned off while adjusting steering trim.
The receiver antenna has been set up and installed from the factory.
When installing the antenna, first slide the antenna wire into the bottom of the antenna tube until the white tip of the antenna is at the top of the tube under the black cap. Next insert the antenna tube into the mount while making sure that antenna wire is in slot in the antenna mount. Do not bend or kink the antenna wire! Do not shorten the antenna tube.
To prevent loss of radio range, do not kink or cut the black wire, do not bend or cut the metal tip, and do not bend or cut the white wire at the end of the metal tip.
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®.
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!
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.
Dirt is the worst enemy to your engine. A clean air filter is absolutely critical for long engine life. Due to the high performance nature of the TRX 3.3 engine, a tremendous amount of vacuum is created to move a large volume of high velocity air through the carburetor. This model is equipped with a two-stage high performance air filter which requires that the pre-filter stage be cleaned and oiled every hour of operation, and the primary filter be cleaned and oiled every 3-4 hours. An extra pre-lubed air filter set has been provided with this model to encourage you to maintain the engine's air filter.
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. 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.
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.
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.
Carb - Abbreviation for carburetor.
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.
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.
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.
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.
Pre-filter - The outer air filter element in a two-stage air filter. This provides the first level of air filtration for the engine. The majority of dirt and debris will be stopped by this filter. Clean, re-oil, and replace this filter after every hour of run time. Always use both the pre-filter and primary filter.
Primary filter - The inner air filter element in a two-stage air filter. This provides a second level of air filtration after the pre-filter removes the majority of dirt and debris. Clean, re-oil, and replace this filter after every 3 - 4 hours of run time. Always use both the pre-filter and primary filter.
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 specially-shaped metal or composite chamber with baffles that is designed to enhance the power output of the engine.
Two-stage air filter - An air filter with two separate, oiled foam filter elements. The outer element, the pre-filter, removes the majority of dirt and debris. The inner element, the primary filter, then filters the air again before it enters the engine. The pre-filter should be cleaned, oiled, and replaced every hour of runtime. The primary filter only requires cleaning and re-oiling every 3 - 4 hours, depending on running conditions.
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.
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.
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.
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.
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.
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.
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.
Handling the Fuel
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 minors 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. Fuel is flammable. Only use outdoors. Keep fuel away from all sources of ignition (flame, sparks, heat, etc.).
Use the included fuel dispensing bottle (Traxxas Top Fueler, part #5001) to put fuel into the T-Maxx'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.
To fill your model flip up the spring-loaded 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.
Fuel Tank Seal Adjustment
The rubber seal on the fuel tank is important to the function of the engine. The fuel tank is pressurized by the exhaust system to provide reliable fuel flow. If the tank lid does not seal properly, an air leak will be created that can cause your engine to run erratically and be difficult to start. If necessary, the rubber O-ring tank seal can be adjusted for improved sealing by tightening the screw on the underside of the tank lid.
The TRX 3.3 Racing Engine in this model is equipped with a specially designed two-stage air filter to deliver maximum filtering efficiency and performance while protecting your engine from dust and dirt during extended operating conditions. 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 two-stage TRX Racing Filter consists of the following components:
You must clean the outer pre-filter after every hour of run time, even if the filter looks clean. The primary filter element inside must be cleaned after 3-4 hours of run time. These intervals include 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.
Pre-Filter Cleaning Instructions (every hour of run time)
Primary Filter Cleaning Instructions (every 3 - 4 hours of run time)
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).
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 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).
The Fuel Mixture Needles
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 high-speed 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.
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 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.
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).
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.
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.
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 instructions on freeing the engine.
The Idle Speed Screw
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.
→ See Tuning Your TRX 3.3 Racing Engine for complete information on adjusting the air/fuel mixture and idle speed.
Factory Needle Settings
If your factory preset carburetor adjustments have been tampered with, use the following settings:
Always use the factory settings for initial starting. Only use these settings when the factory settings have been lost.
The Traxxas EZ-Start brings the convenience of push-button electric engine starting to your T-Maxx. The EZ-Start consists of a hand-held control unit and an on-board motorized starter.
Charging the EZ-Start Battery
The included charger can be used to charge the included EZ-Start battery pack.
Do not charge batteries inside of an automobile. Read the Safety Precautions section of this guide.
Note: If there is a problem with the battery, such as a short circuit, the charger's LED will flash red. Disconnect the battery and unplug the charger from its power source to clear the error. Determine the cause of the error before continuing.
Installing the EZ-Start Battery
Using the EZ-Start
Your EZ-Start controller plugs into a 4-prong receptacle in the center of the bed on your T-Maxx 3.3. 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.
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.
If the Glow Plug LED fails to light, the glow plug may be bad, or the glow plug wire may be damaged or disconnected.
If the Motor LED fails to light and the starter fails to operate, then the EZ-Start is in protection mode.
It's normal for your EZ-Start controller to become warm after repeated use.
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 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.
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.
Use a Strong Starter Battery
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 instructions on freeing the engine.
Shutting Off The Engine
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.
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.
Using Other Chargers
Another convenient option for charging the included battery is an AC peak-detecting charger that plugs directly into an AC wall outlet, such as the EZ-Peak Plus, part #2970. It contains special peak-detection circuitry that automatically shuts the charger off when the battery is fully charged.
Never use a 15-minute timed charger to recharge your model's battery packs. Overcharging may result, causing damage to the battery packs.
The TRX 3.3 Racing Engine uses a ringless, aluminumbrass-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 1,5 hours to complete the break-in procedure. The engine break-in period will take 5 tanks of fuel in a T-Maxx 3.3. The break-in time is not the time to impress your friends with your new T-Maxx 3.3. 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 (included) 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 high-speed running is not permitted until the 6th tank of fuel. Perform the initial break-in on a large, flat, paved surface. T-Maxx 3.3 is very fast and by tanks 4 and 5 you will need plenty of room for the truck to run in. Apply all throttle and braking actions gently. Abrupt acceleration or braking could cause the engine to stall unnecessarily.
→ See Important Points to Remember for other precautions.
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" breakin methods. Even if you have years of experience using model engines, please do not ignore this caution!
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 T-Maxx 3.3 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. We do not recommend running the model in temperatures below 35 degrees.
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 information on clearing a flooded engine
Break-in Checklist
Note: The wheelie bar is installed in the "down" position to help keep the front of the T-Maxx 3.3 down during acceleration. Apply throttle gradually to prevent wheelies during break-in. See wheelie bar adjustment.
Tank 1
TANK | THROTTLE | TIME | COOL | BODY | NOTES |
1 | 1/4 | 2 seconds | 15 minutes | Off | Apply throttle gradually. |
2 | 1/2 | 2 seconds | 15 minutes | On | Apply throttle gradually. |
3 | 1/2 | 3 seconds | - | On | Reduce idle speed if necessary. |
4 | Full | 3 seconds | - | On | Do not allow shifting to high gear. |
5 | Full | 5 seconds | - | On | Accelerate over 3 second count, hold for 2 seconds. |
Tank 2
Tank 3
Tank 4
Tank 5
Tank 6
STOP! Clean your air filter before you proceed. During the sixth tank of fuel, the engine can be tuned for general performance use. Proceed to the next section in this manual.
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.
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.
Follow the remaining break-in procedures as outlined in this Owners Manual. This, along with the steps listed above, will ensure a good breakin for your new nitro engine, and provide many hours of enjoyment.
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:
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.
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:
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.
High-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 high-speed 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 wheelies 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:
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.
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.
Low-Speed Fuel Mixture Adjustment
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".
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 T-Maxx 3.3 from doing a wheelie when you accelerate!
When adjusting the low speed fuel mixture, it is very important to make several high-speed runs with T-Maxx 3.3 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.
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.
Fuel Mixture Adjustment Chart
If the... | is.. | then the air density is... | adjust (correct) the fuel mixture to be... |
Humidity | Lower | Slightly more dense | Slightly richer |
Higher | Slightly less dense | Slightly leaner | |
Pressure (barometer) | Lower | Less dense | Leaner |
Higher | More dense | Richer | |
Temperature | Lower | More dense | Richer |
Higher | Less dense | Leaner | |
Altitude | Lower | More dense | Richer |
Higher | Less dense | Leaner | |
Nitro % | Lower | - | Leaner |
Higher | - | Richer |
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.
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 below provides general guidelines on how weather conditions affect air density when they move higher or lower than your baseline setting (see detailed info on how air density affects mixture settings).
Tuning the Engine by Temperature
Your model is equipped with a temperature sensor to indicate the engine's temperature on the dashboard of the Traxxas Link application (available separately. 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 Traxxas Link application's dashboard 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 rear of 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:
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! Before you go on, here are some important precautions to keep in mind.
Driving Tips
Shock Mounting Positions
Big bumps and rough terrain require a softer suspension with the maximum possible suspension travel and ride height. Racing on a prepared track or on-road use requires a lower ride height and firmer, more progressive suspension settings. The more progressive suspension settings help reduce body roll (increased roll stiffness), dive during braking, and squat during acceleration.
Upper shock mounting position (A) should generally be used with lower shock mounting positions 1 and 2. Upper shock mounting position (B) should be generally be used with lower shock mounting positions 3 and 4. The innermost upper shock mounting position (0) can be used for tuning with the inner pair of lower shock mounting positions on the arm (1,2). It is not compatible with lower shock mounting positions 3 and 4. Other combinations may be used to achieve individualized suspension settings.
Upper Shock Mounting Positions
The upper shock mounting positions will have suspension effects opposite from the lower shock mounting positions.
Spring rate (at the wheel), increases as the upper shock mounting position is moved from position (A) to position (B).
Ride height is not affected by changes in the upper shock mounting position. Use the chart below to see the effect of the various shock mounting positions. The horizontal length of the lines indicates the amount of suspension travel. The angle or slope of the lines indicates the spring rate (at the wheel ).
Lower Shock Mounting Positions
In the out-of-the-box configuration, the shocks are installed in position (A) on the shock tower and position (2) on the lower suspension arm.
This setting allows for firm suspension and low ride height, increasing the spring force (at the wheel). This setting improves high-speed cornering on smoother terrain by lowering the center of gravity. Body roll, brake dive, and squat are also reduced.
The inner pair of holes on the lower suspension arm should be used to increase the ride height of the T-Maxx 3.3. The more vertical position of the shocks will allow for lower shock progression and the soft, plush feel that's characteristic of a Traxxas Maxx Truck.
Spring rate (at the wheel) increases as the lower shock mounting position is moved from position (1) to position (4). This is equivalent to using stiffer springs. Use higher spring rate settings for flatter terrain with smaller and fewer bumps, and lower spring rate settings for bigger bumps.
Ride height decreases as the lower shock mounting position is moved from position (1) to position (4). Each pair of lower shock mounting holes (1,2 and 3,4) has equal ride height. Use lower ride height for highspeed cornering and flat terrain, and when racing on relatively smooth tracks. Increase the ride height for rougher terrain and tracks.
For easier access to the rear-most shock mounting screw, remove the one end of the rear turnbuckle. In the front, remove the suspension pin from the lower front suspension arm to gain easier access to the lower shock mounting screws.
Fine Tuning the Shocks
The eight shocks (oil dampers) on your T-Maxx 3.3 have tremendous 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 sets (front or rear). Piston head selection depends on the range of oil viscosities that you have available. For example, using a two-hole piston with lightweight oil will give you the same damping as a three-hole piston with heavier oil.
We recommend using two-hole pistons with a range of oil viscosities from 30W to 50W (available from your hobby shop). The thinner viscosity oils (30W or less) flow with less resistance and provide less damping, while thicker oils provide more dampening. Use only 100% pure silicone shock oil to prolong seal life. From the factory, the T-Maxx 3.3 uses 40W oil. The ride height for the T-Maxx 3.3 can be adjusted by adding or removing the clip-on spring pre-load spacers. Note that changes in ride height will occur when changes in shock angle or spring rates are made. You can compensate for ride height changes by changing the pre-load spacers on the shocks.
Adjusting the Pivot Ball Caps
The pivot ball caps should be adjusted so that the pivot balls operate freely in the axle carriers with no excess play. Use the provided four-way suspension multi-tool to tighten or loosen the pivot ball cap.
Caster Adjustment
The T-Maxx 3.3 offers the ability to adjust the caster angle of the front suspension. Caster adjustment may be used to influence the understeer/ oversteer handling characteristics of the T-Maxx 3.3. Increasing the caster angle will increase the tendency of the truck to oversteer (less traction on the rear tires, more traction on the front tires), while decreasing the caster angle will cause the truck to have a tendency to understeer (push in the turns). This effect becomes more pronounced at higher steering angles and higher spring rates. Caster is adjusted by repositioning the shims on the pivot point of the upper suspension arms.
The stock caster setting is 7-degrees with one shim at each end of the arm. Reduce the caster angle to 4-degrees by removing the rear shim and inserting it next to the front shim. The caster angle can be increased to 10-degrees by removing the front shim and inserting it next to the rear shim.
Wheel Force vs. Wheel Travel
Adjusting the Toe-in
Your T-Maxx 3.3 comes from the factory with zero degrees of toe-in in the front, and one degree of toe-in in the rear. You can adjust the toe-in on the front and rear of the truck. Set the steering trim on your transmitter to neutral. Next, adjust your steering turnbuckles so that both front 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. Adjust the rear toe control links so that the rear wheels have 1˚ of toe-in.
Static Camber Adjustment
The wheels can be set to have either positive or negative camber (see illustration below). The camber angle changes as the wheel moves up and down through its range of travel. Static camber is the camber angle at the wheel when the vehicle is set at its normal, stationary ride height.
The suspension pivot balls located in the axle carriers adjust the static camber. The pivot balls are protected by blue dust plugs. To adjust your static camber, insert the supplied 2.5mm hex wrench through the slit in the dust plug and engage the end of the pivot ball (compressing the suspension until the arms are parallel to the ground will allow for easier hex wrench engagement). The upper pivot ball is normally screwed all the way in. Negative camber is achieved by screwing the pivot ball of the lower control arm out.
Note: When camber is changed, the toe angle of the wheel has to be reset.
Static Camber Base Factory Settings
Front: 1-degree negative camber each side
Rear: 1-degree negative camber each side
Adjusting the Slipper Clutch
Your T-Maxx 3.3 is equipped with an adjustable Torque Control slipper clutch. The slipper clutch is integrated into the main spur gear on the transmission. The slipper clutch is adjusted using the springloaded locknut on the slipper shaft. Use the supplied 8mm open-end metric wrench. To tighten or loosen the slipper nut, insert the 2.0mm hex wrench into the hole in the end of the slipper shaft. This locks the shaft for adjustments. Turn the adjustment nut clockwise to tighten (less slippage) and counter-clockwise to loosen (more slippage). The slipper clutch has two functions:
From the factory, the slipper clutch is set for minimal slippage, to protect the drivetrain from shock loads. On slippery, low traction surfaces such as a hard-packed, dry racetrack you may benefit from loosening the slipper adjustment nut to allow for more clutch slippage. This will make the truck easier and more forgiving to drive by helping to reduce the amount of wheel spin. Loosening the slipper adjustment can also improve performance on extreme high traction surfaces by preventing the front end from lifting off of the ground when accelerating. Make slipper adjustments in small 1/8 turn increments.
The maximum tight setting for the slipper is just at the point where there is little or no tire slippage on a high traction surface such as concrete or a prepared racetrack. The slipper should not be tightened to the point that clutch slippage is completely eliminated. Do not overtighten the slipper nut or you could damage the slipper bearings, pressure plates, or other components.
All of the toe links are installed on the truck so that the left hand thread indicators point in the same direction. This makes it easier to remember which way to turn the wrench to increase or decrease toe link length (the direction is the same at all four corners). Note that the groove in the hex indicates the side of the toe link with the left-hand threads.
Adjusting the Two-Speed Transmission
T-Maxx 3.3 comes equipped with an adjustable two-speed transmission. When the shift point on the transmission is adjusted correctly, it will maximize acceleration and improve drivability. Use a 2mm hex wrench to adjust the shift point. To make the adjustment, the engine must be off (not running).
Changing the Spur Gear
Adjusting the Gear Ratio
The gear ratio on T-Maxx 3.3 can be adjusted for different conditions that may require either increased acceleration or increased top speed. Adjusting the gear ratio is accomplished by changing the clutch bell on the engine and/or the spur gear (slipper clutch gear) on the transmission. From the factory, T-Maxx 3.3 is equipped with a 22-tooth clutch bell and a 55-tooth spur gear. This combination will provide a good balance of acceleration and top speed. Optional spur gears and clutch bell gears are listed on your parts list. Refer to the chart below for possible gearing combinations.
Adjusting the Spur Gear/Clutch Bell Gear Mesh
The ideal spur gear/clutch bell gear mesh for T-Maxx 3.3 is 0.1mm. To set the gear mesh, place a strip of standard letter/A4 size copy or printer paper (about 0.1mm thick) between the mating teeth. Loosen the four engine mount screws from the bottom side of the chassis (see image) and slide the engine mount up to push the clutch bell gear against the spur gear so the paper is not too tight to pull out or too loose that it will fall out. Tighten the engine mount screws securely. When the paper is removed, you should feel only the slightest amount of play between the gears (almost none) and there should be no binding or friction.
Adjusting the Two-Speed Ratios
T-Maxx 3.3 is equipped to allow adjustment to the 2-speed by installing optional close and wide-ratio gearsets. This requires transmission removal and disassembly (see www.Traxxas.com for detailed instructions). The close ratio gearsets will reduce top speed slightly but will provide more powerful acceleration by reducing engine rpm loss when shifting from 1st gear to 2nd gear. The wide ratio gear set is designed for wide open areas and will increase top speed, but reduce acceleration due to greater rpm loss when shifting gears.
The gear ratio chart above shows the available combinations with optional spur gears, clutch bells, and two-speed gear sets.
T-Maxx 3.3 is equipped with a disc brake that rides on the yoke of the transmission's front output shaft. The brake is preset at the factory and should not require attention. As the brake material wears, future adjustments may be necessary.
Brake Shoulder Screw Adjustment
The two shoulder bolts that are used to secure the brake pads to the transmission housing may need to be adjusted periodically as the brake material wears down. They should be tightened so a 0.50mm (.020") gap exists between the disc and the brake pad (on the transmission side). Adjust in one of the following ways:
Brake Pad Wear and Replacement
During normal use the brake pads should wear at a relatively slow rate. However, if the brake pads wear down close to the metal pad holders, they should be replaced. Any more wear than this could cause damage to the brake parts and improper operation of the brake system.
Wheelie Bar Installation
The Maxx Wheelie Bar can be used on any Maxx truck with the stock rear skid plate, rear bumper, and rear bumper mounts. It is also compatible with the Traxxas accessory aluminum rear bumper (part #4935X). The wheelie bar is intended for use on hard, high-traction surfaces, such as pavement, where controlling wheelies can be difficult. It is easily removed for off-road racing or jumping.
Wheelie Bar Setup Instructions
Changing the position of the wheelie bar height setting is easier when the wheelie bar is installed on the truck. Snap the upper arms off of the wheelie position cross bars. Move the upper arms to the desired wheelie position cross bar and then snap them in place.
Each setting can offer different results based on the individual ride height and droop settings for a particular truck. Try to avoid riding on the wheelie bar wheels during normal driving (this can happen in the lowest setting with lower than stock ride heights).
Remove the wheelie bar when the T-Maxx will be jumped or driven in harsh off-road conditions.
Your T-Maxx 3.3 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:
After each running session:
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 with Traxxas Power-UP. It could save you time and effort. Details are in your model's documentation package.
Other periodic maintenance:
After-run Procedure
You must perform after-run maintenance on your TRX 3.3 Racing 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:
The TRX 3.3 Racing Engine 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.
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:
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:
The model's TQi transmitter is equipped with the Traxxas Link Wireless Module. This innovative accessory transforms your Apple® iPhone®, iPad®, iPod touch®, or Android device into a powerful TM tuning tool that equips your TQi with an intuitive, high-definition, fullcolor graphical user interface.
Traxxas Link
The powerful Traxxas Link App (available in the Apple App Store SM or on Google Play ) gives you complete TM control over the operation and tuning of your Traxxas model with stunning visuals and absolute precision. With the installed Traxxas Link telemetry sensors on the model, Traxxas Link displays real-time data such as speed, RPM, temperature, and battery voltage.
Intuitive iPhone, iPad, iPod touch, and Android interface
Traxxas Link makes it easy to learn, understand, and access powerful tuning options. Control Drive Effects settings such as TSM assistance percentage; steering and throttle sensitivity; steering percentage; braking strength; and throttle trim by simply touching and dragging the sliders on the screen.
Real-Time Telemetry
With the installed telemetry sensors, the Traxxas Link dashboard comes to life showing you speed, battery voltage, RPM, and temperature. Set threshold warnings and log maximums, minimums, or averages. Use the recording function to document your dashboard view, with sound, so that you can keep your eyes on your driving and not miss a single apex.
Starting Over: Restoring Factory Defaults
When programming your TQi transmitter, you may feel the need to start over with a clean slate. Follow these simple steps to restore the factory settings:
Manage up to 30 Models with Traxxas Link
The TQi radio system automatically keeps track of what vehicles it has bound to and what settings were used for each--up to 30 models total! Traxxas Link provides a visual interface to name the models, customize their settings, attach profiles, and lock them into memory. Simply choose a model and any previously bound transmitter, power them up, and start having fun.
Pairing the TQi transmitter with the Traxxas Link Wireless Module and the Traxxas Link App for the first time:
LED Color / Pattern | Name | Notes | |
![]() | Blue LED off | Connecting mode | Traxxas Link App is not running on a paired device. |
![]() | Slow blue (0.5 sec on / 0.5 sec off ) | Pairing mode | See above for information on pairing the module with Traxxas Link App. |
![]() | Solid blue | Connected | See information on how to use your transmitter controls. |
Available Tuning Adjustments
The following items can be adjusted most easily using your mobile device and the Traxxas Link application. All the features described below may also be accessed using the menu and set buttons on the transmitter and observing signals from the LED.
Your Traxxas transmitter has a programmable Multi-Function knob that can be set to control various advanced transmitter functions (set to Traxxas Stability Management (TSM) by default. Experiment with the settings and features to see if they can improve your driving experience.
Steering Sensitivity (Exponential)
The Multi-Function knob on the TQi transmitter can be set to control Steering Sensitivity (also known as exponential). The standard setting for Steering Sensitivity is "normal (zero exponential)," with the dial full left in its range of travel. This setting provides linear servo response; the steering servo's movement will correspond exactly with the input from the transmitter's steering wheel. Turning the knob clockwise from center will result in "negative exponential" and decrease steering sensitivity by making the servo less responsive near neutral, with increasing sensitivity as the servo nears the limits of its travel range. The farther you turn the knob, the more pronounced the change in steering servo movement will be. The term "exponential" comes from this effect; the servo's travel changes exponentially relative to the input from the steering wheel. The exponential effect is indicated as a percentage— the greater the percentage, the greater the effect. The illustrations below show how this works.
Normal Steering Sensitivity (0% exponential):
In this illustration, the steering servo's travel (and with it, the steering motion of the model's front wheels) corresponds precisely with the steering wheel. The ranges are exaggerated for illustrative purposes.
Decreased Steering Sensitivity (Negative Exponential):
By turning the Multi-Function knob clockwise, the steering sensitivity of the model will be decreased. Note that a relatively large amount of steering wheel travel results in a smaller amount of servo travel.
The farther you turn the knob, the more pronounced the effect becomes. Decreased steering sensitivity may be helpful when driving on low-traction surfaces, when driving at high speed, or on tracks that favor sweeping turns where gentle steering inputs are required. The ranges are exaggerated for illustrative purposes.
Throttle Sensitivity (Throttle Exponential)
The Multi-Function knob can be set to control Throttle Sensitivity. Throttle Sensitivity works the same way as Steering Sensitivity, but applies the effect to the throttle channel. Only forward throttle is affected; brake/reverse travel remains linear regardless of the Throttle Sensitivity setting.
Steering Percentage (Dual Rate)
The Multi-Function knob can be set to control the amount (percentage) of servo travel applied to steering. Turning the Multi-Function knob fully clockwise will deliver maximum steering throw; turning the knob counter-clockwise reduces steering throw (note: turning the dial counter-clockwise to its stop will eliminate all servo travel). Be aware that the steering End Point settings define the servo's maximum steering throw. If you set Steering Percentage to 100% (by turning the Multi-Function knob fully clockwise), the servo will travel all the way to its selected end point, but not past it. Many racers set Dual Rate so they have only as much steering throw as they need for the track's tightest turn, thus making the car easier to drive throughout the rest of the course. Reducing steering throw can also be useful in making a car easier to control on high-traction surfaces, and limiting steering output for oval racing where large amounts of steering travel are not required.
Braking Percentage
The Multi-Function knob may also be set to control the amount of brake travel applied by the servo in a nitro-powered model. Electric models do not have a servo-operated brake, but the Braking Percentage function still operates the same way in electric models. Turning the Multi- Function knob full clockwise will deliver maximum brake throw; turning the knob counter-clockwise reduces brake throw (Note: Turning the dial counter-clockwise to its stop will eliminate all brake action).
Steering and Throttle End Points
The TQi transmitter allows you to choose the limit of the servo's travel range (or its "end point") independently for left and right travel (on the steering channel) and throttle/brake travel (on the throttle channel). This allows you to fine-tune the servo settings to prevent binding caused by the servo moving steering or throttle linkages (in the case of a nitro car) farther than their mechanical limits. The end point adjustment settings you select will represent what you wish to be the servo's maximum travel; the Steering Percentage or Braking Percentage functions will not override the End Point settings.
Failsafe
Your Traxxas radio system is equipped with a built-in failsafe function that returns the throttle to its last saved neutral position in the event of a signal loss. The LED on the transmitter and the receiver will rapidly flash red.
Steering and Throttle Sub-Trim
The Sub-Trim function is used to precisely set the neutral point of the steering or throttle servo in the event that simply setting the trim knob to "zero" does not completely center the servo. When selected, Sub-Trim allows finer adjustment to the servo output shaft's position for precise setting of the neutral point. Always set the Steering Trim knob to zero before making final adjustment (if required) using Sub-Trim. If Throttle Trim has been previously adjusted, the Throttle Trim will need to be reprogrammed to "zero" before making final adjustment using Sub-Trim.
Throttle Trim
Setting the Multi-Function knob to serve as throttle trim will allow you to adjust the throttle's neutral position to prevent unwanted brake drag or throttle application when the transmitter trigger is at neutral.
Note: Your transmitter is equipped with a Throttle Trim Seek mode to prevent accidental runaways. See the below for more information.
Throttle Trim Seek Mode
When the Multi-Function knob is set to throttle trim, the transmitter remembers the throttle trim setting. If the throttle trim knob is moved from the original setting while the transmitter is off, or while the transmitter was used to control another model, the transmitter ignores the actual position of the trim knob. This prevents the model from accidentally running away. The LED on the face of the transmitter will rapidly blink green and the throttle trim knob (Multi-Function knob) will not adjust the trim until it is moved back to its original position saved in memory. To restore throttle trim control, simply turn the multi-function knob either direction until the LED stops blinking.
Setting Lock
Once you've adjusted all of these settings the way you like them, you may want to disable the Multi-Function knob so none of your settings can be changed. This is especially handy if you operate multiple vehicles with a single transmitter via Traxxas Link ™ Model Memory.
Multiple Settings and the Multi-Function Knob
It is important to note that settings made with the Multi-Function knob are "overlaid" on top of each other. For example, if you assign the Multi-Function to adjust Steering Percentage and set it for 50%, then reassign the knob to control Steering Sensitivity, the transmitter will "remember" the Steering Percentage setting. Adjustments you make to Steering Sensitivity will be applied to the 50% steering throw setting you selected previously. Likewise, setting the Multi-Function knob to "disabled" will prevent the knob from making further adjustments, but the last setting of the Multi-Function knob will still apply.
LED Color / Pattern | Name | Notes | |
![]() | Solid green | Normal Driving Mode | See information on how to use your transmitter controls. |
![]() | Slow red (0.5 sec on / 0.5 sec off ) | Binding | See more information on binding. |
![]() | Flashing fast green (0.1 sec on / 0.15 sec off ) | Throttle Trim Seek Mode | Turn the Multi Function knob right or left until the LED stops flashing. See above for more information. |
![]() | Flashing medium red (0.25 sec on / 0.25 sec off ) | Low Battery Alarm | Put new batteries in the transmitter. |
![]() | Flashing fast red (0.125 sec on / 0.125 sec off ) | Link Failure / Error | Transmitter and receiver are no longer bound. Turn the system off and then back on to resume normal operation. Find source of the link failure (ie out of range, low batteries, damaged antenna). |
Programming Patterns | |||
![]() | Counts out number (green or red) then pauses | Current menu position | See Menu Tree for more information. |
![]() | Fast green 8 times | Menu setting accepted (on SET) | |
![]() | Fast red 8 times | Menu SET invalid | User error such as trying to delete a locked model. |
LED Color / Pattern | Name | Notes | |
![]() | Solid green | Normal Driving Mode | See information on how to use your transmitter controls. |
![]() | Slow red (0.5 sec on / 0.5 sec off ) | Binding | See more information on binding. |
![]() | Flashing fast red (0.125 sec on / 0.125 sec off ) | Fail-Safe / Low Voltage Detect | Consistent Low Voltage in the receiver triggers Fail-Safe so there is enough power to center the throttle servo before it completely loses power. |
Traxxas Link Model Memory is an exclusive, patent-pending feature of the TQi transmitter. Each time the transmitter is bound to a new receiver, it saves that receiver in its memory along with all the settings assigned to that receiver. When the transmitter and any bound receiver are switched on, the transmitter automatically recalls the settings for that receiver. There is no need to manually select your vehicle from a list of model memory entries.
Model Lock
The Traxxas Link Model Memory feature can store up to thirty models (receivers) in its memory. If you bind a thirty-first receiver, Traxxas Link Model Memory will delete the "oldest" receiver from its memory (in other words, the model you used the longest time ago will be deleted). Activating Model Lock will lock the receiver in memory so it cannot be deleted.
You may also bind multiple TQi transmitters to the same model making it possible to pick up any transmitter and any previously bound model in your collection and simply turn them on and drive. With Traxxas Link Model Memory, there is no need remember which transmitter goes with which model and there is never a need to have to select any model from a list of model memory entries. The transmitter and receiver do it all for you automatically.
To activate Model Lock:
To delete a model:
At some point, you may wish to delete a model you no-longer drive from the memory.
The menu tree below shows how to navigate through the TQi transmitter's various settings and functions. Press and hold MENU to enter the menu tree, and use the following commands to navigate through the menu and select options.
MENU: When you enter a menu, you always start at the top. Press MENU to move down the menu tree. When you reach the bottom of the tree, pressing MENU again will return you to the top.
SET: Press SET to move across the menu tree and select options. When an option is committed to the transmitter's memory, the status LED will rapidly blink green.
BACK: Press both MENU and SET to go back one level in the menu tree.
EXIT: Press and hold MENU to exit programming. Your selected options will be saved.
ECHO: Press and hold SET to activate the "echo" function. Echo will "play back" your current position on the Menu Tree, should you lose your place. For example: If your current position is Steering Channel End Points, holding SET will cause the LED to blink green twice, green once, and then red three times. Echo will not alter your adjustments or change your position in the programming sequence.
Below is an example of how to access a function in the menu tree. In the example, the user is setting the Multi-Function knob to be a Steering % (Dual Rate) control.
To set the Multi-Function knob to control STEERING % (DUAL RATE):
Restoring Factory Defaults:
Transmitter OFF | Hold both MENU and SET | Transmitter ON | Release MENU and SET. Red LED blinks | Press MENU four times. Red LED blinks 5 times | Press SET to clear settings. LED will turn solid green. Transmitter is restored to default |
*Torque Control is a feature designed only for use with the power system in the Traxxas Funny Car Race Replica (Model #6907).
6250 Traxxas Way, McKinney, Texas 75070
1-888-TRAXXAS
Here you can download full pdf version of manual, it may contain additional safety instructions, warranty information, FCC rules, etc.
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