There isn't really an "average price" unless you specify the size you are seeking. They make nitro rc engines for cars, they also make them for airplanes, so you would need to be more specific.
The Cox .010 nitro engine
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it is a remote controlled car that uses a nitro engine to power it the nitro engine is a small 2 stroke engine that runs off of nitro fuel and these cars can go very fast and have lotxs of pwer
Mostly by engine temperature but also the sound of the engine.
Any nitro, ranging between 5% and 30% nitro. Anything more would clog the engine.
There are many companies that make Nitro RC cars. These companies include: Hobby Town USA, Traxxas, Exceed RC, and many other big businesses. The best Nitro RC car company is Traxxas. They have the best RC cars available but are very expensive.
If you mean an engine that runs on Nitromethane I think they are no different than the normal RC engine. the engines and the fuel can be purchased at most hobby shops.
No other fuels should be used except nitro.
RC Nitro cars are remote control toy cars that people use or race as hobbies. The best place to buy a RC Nitro car is at a store that carries the car and the best time is when it is on sale for the cheapest price.
It rattles very loudly when not moving.
HPI and REVOS are pretty good.
If it is NITRO powered you use anywhere from 20% nitro fuel to 33% nitro fuel. Traxxas top fuel is the best fuel for nitro cars.