Why and How Do You Mod a Nitro Engine?

Engine on a Nitro Traxxas Rustler.
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Question: Why and How Do You Mod a Nitro Engine?

Modding a nitro engine means that you are making a modification that is or seems to make the engine better than factory specs. Modding goes beyond simply tuning your nitro engine. It involves making physical changes the engine itself.

Answer: While things like adjusting fuel flow and air intake or changing the type of fuel can affect engine performance, they are not modifications.

The type of modifications described here are irreversible. Modding a nitro engine could mean making adjustments to the connecting rod by grinding a small portion of metal off of the connecting rod. Another modification is what is called fanging the piston sleeve which is the process of removing material from the sleeve's intake and exhaust ports in a way that resembles fang like shapes cut into said ports. This requires a dremmel or a small high speed rotary tool.

There is a lot of discussion among nitro RC owners about what can be done to get a little more out of a stock RC nitro engine.

Why mod a nitro engine?

Certain modifications can help smooth out or streamline the performance of your nitro engine. This includes things such as better top end, smoother acceleration, and better torque ranges just to name a few. Modifications like these can even be done to try to get better run time out of a tank of fuel.

By doing a couple of modifications to the crank, piston sleeve and even going as far as to modify the connecting rod of the piston itself can help your nitro engine exceed stock motor performance.

Improve nitro performance without modifications

Modding your nitro engine is not the only way, and arguably the least desirable way, to increase engine performance for most RC nitro owners.

So, before you mod, consider non-destructive ways to get more from a engine.

On YouTube, Squirrelod has an excellent video series that goes over the process of tuning a nitro engine from basic to advanced techniques. This helps get the most out of what your stock nitro engine without complicated and costly modifications. His playlist kinda jumps around so just scroll down through the play list, all 14 videos are there. These videos help you go from tuning basics, finding and remembering your stock needle setting to the compression of a nitro engine. If you want to jump to a certain video in the series here is a title list. I recommend watching them in order to get the whole picture of what it takes to tune your nitro engine. Who knows you might learn something new, I know I did.

  1. Tuning basics
  2. Stock needle settings
  3. Weather effects
  4. Fuel and glow plugs
  5. Shims
  6. Reading engine temps
  7. Onsite HSN tuning
  8. Onsite LSN tuning
  9. Onsite Idle screw tuning
  10. Running signs of rich, lean, and tuned
  11. Glow plugs 101
  12. Air leak detection
  13. Sealing air leaks
  14. Compression 101

If you prefer reading to video, RC Hobbies Online offers a good, indepth discussion on how to tune your nitro engine, including a visual representation of which way to lean or richen the fuel mixture due to weather changes.

This visual aid helped me out tremendously since I often forget to do this step from time to time.

Dangers and cost of modding a nitro engine

Now all of these things might seem fun or useful to do but be forewarned: If you don't know or have never done nitro engine modding before you can seriously damage your nitro engine — even destroy it if not done properly. As I mentioned previously, most modifications are irreversible. To go back to stock you'll need to replace the parts you modified or buy a whole new engine. Not to put too fine a point on it but, if you're not careful enough it could cost you hundreds of dollars even if the initial cost was for a rotary tool and some stray spare parts.

Modding a nitro engine isn't for everyone. Especially not for those who are unsure of themselves, have shaky hands, and can't afford to loose an engine.

If you have never touched a rotary tool I would not recommend this as a way to get familiar with using one. Practice carving on a piece of wood for that.

The reason I give you all of these warnings is not because I don't think some modding is useful but because I want you to know the process and skills that it takes before you jump in feet (or rotary tool) first. My son Tyler loves the various modifications I do to all my RCs but that doesn't mean he's going to jump right in and start grinding away at the engine of his $300.00+ nitro RC to make it go faster. He opted to take the easier route and just upgraded by installing manufactured performance parts. Smart kid.

How to mod a nitro engine

Once you've decided that you want to go beyond the scope of stock nitro engines and standard upgrades you're going to need to decide what mods to make and learn how to do it.

If you are handy with small metal files and rotary tools modding isn't particularly difficult. At least handling the tools won't be. Now, knowing just how much to grind, shave and cut away is a different story. There are a lot of formulas that go into modifying a nitro engine the right way.

Although there are a select few people that have been quite successful in doing this just from looking at some pictures that others have done and reading descriptions of the process, I myself have only practiced on engines that I deemed inoperable. So knowing whether or not I'm doing it right is still a mystery. So claiming that I have done this successfully would be guessing at best.

Therefore, for the real scoop on how it's done I'm turning it over to others.

  • Nitro Motor Mod
    After several warnings which echo much of what I've said in this FAQ, this E-Maxximum RC article takes you through the steps for doing some nitro engine mods. A good tip: "you may want to experiment on a motor with a piston and sleeve that’s nearly shot. That way, if you screw things up you won’t be sending your motor to a (much) earlier grave."


  • Traxxas TRX-15 PRO Engine Modification
    Although written for a specific engine, this tutorial provides plenty of general information. It describes and illustrates needed tools, gives tips, and explains why you may want to do certain modifications.


  • RC Universe Forum
    These forum discussions can also help with knowing what and how to do some of the processes involved but they don't cover everything.

Want a modified nitro engine but not ready to tackle it yourself? Perhaps one of these sites can help. They do tuning and modifications on your RC. Please note that I have no personal experience with any of these sites so investigate them as you would any company you plan to do business with over the Internet.


As I have said and as you'll read in the linked tutorials, modding an RC nitro engine can enhance performance but it is not a task to be undertaken on a whim. It's not necessarily difficult or expensive if done right, but mistakes can be costly and can render your nitro engine useless. I'm not saying don't do it. But do your homework before attempting it.