Tuning a nitro RC engine is a simple process assuming you understand the basics of how a nitro engine works and the components of the engine and fuel system are in good working order. Luckily, there is an amazing video by Invisible Speed RC on YouTube that explains how a nitro engine works an how to tune nitro engines. It is over an hour long, but is a must-watch. I suggest you don’t go any further until you’ve watched this video. Personally, I watched it 3 times before I attempted to tune my first nitro RC.
Tuning is easy
Once you understand the basics of nitro engines and tuning, the tuning process can be summarized as follows:
- Reset the carburetor to factory settings (found in manual).
- Start the nitro engine with the wheels off the ground.
- Adjust the idle stop so the engine is at a low idle and the wheels are not spinning.
- Warm up the engine with some light driving for 5-10 minutes.
- If idle changes, adjust the idle stop and low end as needed to keep the car running and to prevent excessive wear on the clutch/brakes.
- Do some full throttle passes to tune the high end for optimal performance.
- After the high end is dialed in, tune the low end response for optimal performance.
- Fill the tank back to 1/2 or 3/4 full and tweak the tune as needed.
If you don’t understand nitro engines and tuning, the above won’t make any sense.
If something is wrong with the carburetor, fuel system, or engine, the above will be challenging or impossible.
If you’ve never tuned a nitro engine before, the tuning process can take 20 minutes or more. Once you know what you’re doing, you will have your nitro tuned and ready to bash in a few minutes after warming up the engine.
Tune your nitro every time you run it
Every single time you run your nitro, you need to tune it. This is just a fact of nitro engines as they will run a little different based on the environmental conditions which are never exactly the same. You might even need to tune your nitro twice if a sunny day all the sudden goes cloudy. The good thing is that tuning a nitro engine is fun. When I run my nitro, the tune is always in the back of my mind and I’m always ready to turn a screw on the carburetor.
If you run your nitro engine without tuning it or if you fail to re-tune when the tune changes, the engine could start running lean and damage to the engine.
Chasing the tune
Sometimes a nitro engine won’t hold a tune, which means the tune keeps changing and you have to keep adjusting the carburetor to keep the tune. In other words, you are chasing the tune. This can happen for multiple reasons:
- Low quality or faulty carburetor
- Carburetor requires maintenance (clean and replace o-rings/seals)
- Air leak in the fuel system
- Air leak in the engine
When the engine won’t hold a tune, it’s time to do a full inspection of the carburetor, engine, and fuel system.
Here’s another great video on tuning your nitro RC. I suggest watching this after the Invisible Speed RC video linked above.
Can I supercharge or boost my nitro RC engine?
There is a supercharger product on the market for nitro RC engines, but it simply doesn’t work. Nitro RC engines won’t hold additional boost like certain types of two-stroke engines or four-stroke engines. Many people have tried adding a supercharger to their nitro RC engine and no one has any proof that does anything besides add a cool supercharger sound.
Nitrous oxide injection is also something you can add to your nitro RC engine and it does work, but it also throws your engine out of tune every time you hit the nitrous. So if your engine is tuned perfectly and then you hit the nitrous, it will run lean while the nitrous is in the combustion chamber, which is terrible for your engine. You could tune your engine really rich and then have it run optimally when you hit the nitrous, but that doesn’t make much sense.
If you want to get more out of your engine, the simplest thing to do is run 30% nitro fuel.