What Is a Nitro Engine and How Do You Mod It?

Engine on a Nitro Traxxas Rustler.
Engine on a Nitro Traxxas Rustler. | Your Questions, Answered | FAQ Categories: Features | Operating RCs | Airplanes | Subs | Nitro RCs | Tires & Wheels | Painting RCs. © M. James

Most radio-controlled vehicle enthusiasts eventually want to try their hand at modifying the nitro engines that come stock with their cars or trucks—that is, making the kinds of physical changes that will improve performance above and beyond factory specs. Check any forum frequented by nitro RC owners, and you'll find a number of lively discussions about how to get more out of a stock engine.

What Does Mod Mean?

While adjusting fuel flow and air intake or changing the type of fuel can affect engine performance, they are not modifications. We're talking about mods that are irreversible. This kind of work could include making adjustments by grinding a small portion of metal off of the connecting rod, or "fanging" the piston sleeve, which is the process of removing material from the sleeve's intake and exhaust ports to create fang-like shapes cut into said ports. These kinds of mods require a Dremel or similarly small, high-speed rotary tool.

Why Modify a Nitro Engine?

Certain modifications can help streamline the performance of your nitro engine, improving top end, smoothing acceleration, and achieving better torque ranges, just to name a few. Other modifications can even improve fuel efficiency. By doing a couple of modifications to the crank and 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.

Non-Mod Improvements

Modding your nitro engine is not the only way, and arguably it is often considered the least desirable way, to increase engine performance for most RC nitro owners. In fact, if you mess up, you're out an engine. So before you mod, consider non-destructive ways to get more from an engine.

YouTubers like Squirrelod and Average Joe Nitro offer excellent videos that go over the process of tuning a nitro engine from basic to advanced techniques. This will help you get the most out of your stock nitro engine without complicated and costly modifications. Search around a bit and you'll find videos not only on tuning basics, but on stock needle settings, weather effects, fuel and glow plugs, shims, how to read engine temperatures, HSN and LSN tuning, idle crew tuning, glow plugs, detecting and sealing air leaks, compression, and the signs of an engine that runs rich, lean, and tuned.

If you prefer reading to video, Radio Control Car Action online offers a good, in-depth discussion on how to tune your nitro engine.

Downsides to Modifying a Nitro Engine

If you have never done nitro engine modding before you can seriously damage your engine—even destroy it if not done properly. As 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, modifying 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/or can't afford to loose an engine. If you have never touched a rotary tool, this is not the time to get familiar with using one. Practice carving on a piece of wood or working on a less critical project first.

That's not to say that some modding isn't useful, but it's best to take some time to understand the process and develop the skills necessary for success.

Ready to Mod?

Once you've decided that you are ready to go beyond the scope of stock nitro engines and standard upgrades, you're going to need to decide what mods to make and figure out how to make them.

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 successful doing this just by looking at some pictures and reading descriptions of the process, it's best to first practice on engines deemed inoperable. Searching YouTube channels, websites devoted to modifying a specific engine, or forums like RC Universe are great places to start. Also, check with your local RC hobby shop—they'll likely be able to hook you up with likeminded enthusiasts from whom you can learn.