You need to read this article if you’re thinking of using regular gas in your nitro RC car. There are no advantages of doing so and there are some serious dangers attached as well.
A nitro RC car can’t run on regular gas because it doesn’t react with the glow plug as well as nitro fuel and doesn’t have enough oil to lubricate the engine. RC nitro fuel is formulated to burn perfectly while lubricating the engine. Nitro engines are also too small and fragile for gas.
So normal gas could literally blow your nitro engine into pieces because it’s so delicate. The thickness of the engine walls is thinner than that of a gas engine.
Nitro fuel runs much cooler than gas, which is why nitro RC cars require so little active cooling. But there’s more to it than that. Let’s look at what else could happen when using gas in an RC car.
What Happens If You Put Petrol In A Nitro RC Car?
The most likely symptom will be that the petrol doesn’t ignite when it interacts with the glow plug element. This means that the engine won’t start up, and if it does, it will cut out shortly thereafter. Even if the fuel ignites, it might break the engine.
The other problem is if you manage to run gas in it for a few minutes, the engine will probably overheat and seize because of the higher combustion temperature of regular gas. Of course, along with the higher temperatures, there’s also not enough oil in gas to lubricate the engine, which exponentially increases the odds of seizing it.
If you’re thinking of adding 2-stroke oil to the gas for engine lubrication, it may help, but it’s still not the optimal formula for the glow plug to ignite and the engine won’t have enough cooling to run safely.
The Difference Between Gas And Nitro RC Cars
The main difference is that nitro engines use a glow plug to ignite the fuel, fuel that doesn’t run as hot as normal gas. Gas-powered engines use spark plugs to ignite the fuel at higher temperatures. So nitro engines are smaller, lighter, and more fragile than their gas counterparts. This makes them perfect for small vehicles like RC cars and planes.
Gas-powered RC cars are a lot bigger than nitro RC cars because the engine is bigger, they’re usually around 1:5 in scale where nitro RC cars are 1:8 scale and smaller.
Gas-powered RC cars require more maintenance because they have more parts to take care of. For all these reasons and others, nitro RC cars have complete dominance over gas RC cars in terms of popularity.
Fuel Made For Nitro RC Cars
RC Nitro fuel is made with a combination of methanol, nitromethane, and oil. Although the nitromethane is not strictly necessary. First, let’s look at what each ingredient does.
Methanol is the main ingredient and reacts with the glow plug. It ignites to create combustion for your engine to turn.
Nitromethane is the fast burning fuel that is added in varying percentages depending on the application. 10% nitromethane is used for long-lasting runs and low fuel consumption, while a formula with 40% (maximum) nitromethane is used for high-speed racing and burns down quickly. Although you’ll find nitromethane in pretty much all RC fuels, it’s actually not required and many people make their own fuel. A combination of 75% methanol and 25% AA castor oil can be used with no problem.
Please see my article covering nitromethane percentages: Nitro Fuel 20 vs 30: Which One Should You Choose?
The oil lubricates the engine in the same way 2-stroke oil does in gas engines. But for nitro engines, the percentage of oil will depend on the amount of nitromethane added. A popular mix from retailers is around 14% oil with 20% nitromethane and methanol for the rest.
For a really detailed look at nitro fuel, please check out my article: What Is Nitro Fuel Made Of?
Why RC Engines Run On Nitro
RC engines run on nitro because it’s a smaller solution for a vehicle 1/8th the size of a car or smaller. Equipping an RC car with a gas engine usually means going big, at least 1:5 in scale, because a normal gas engine is bigger and heavier than a nitro engine.
The nitro fuel made for RC cars is the perfect formula to get the optimal performance out of a car so small. Nitro fuel doesn’t run as hot as gas, so cooling requires fewer parts, which reduces the overall weight of the car.
Finally, adding oil to the fuel instead of using a crankcase further reduces the weight and volume of the vehicle. The design of the nitro RC engine was well thought out in order to get the maximum performance out of an engine so physically small.
Related article: How Long Will An RC Nitro Engine Last? With Tips To Maintain It
How Long Nitro Fuel Lasts
Nitro fuel can last for years in a cool, dark area, in a sealed container. If the container isn’t airtight, the potency of the fuel will degrade quickly.
How long nitro fuel lasts in your car will depend on the size of the engine and how hard you push it.
Do Nitro RC Cars Need Oil?
Nitro RC cars need only the oil that’s mixed in with the nitro fuel for lubrication. Nitro engines work much the same as other two-stroke engines that require oil in the fuel. The amount of oil in the fuel can vary from 7% to 25% with the average around 15%. RC nitro cars don’t take oil separately to the fuel.
It’s a terrible idea to put regular gas into a nitro RC car because the engine is built differently and doesn’t work the same internally. (Glow plug vs spark plug) Most nitro and gas RC engines are 2-cycle (2-stroke) but that’s where the similarities end. Nitro RC engines with glow plugs aren’t suited to ignite regular gas/petrol and gas doesn’t have the lubrication for the nitro engine.
But don’t use a 2-stroke oil and gas mix either, because it’s not suitable for the glow plug to ignite and has higher operating temperatures compared to an RC nitro fuel mix.
There are many reasons RC nitro engines are designed in this way, so stick to buying nitro fuel consisting of methanol, nitromethane, and oil. The nitromethane is the only optional ingredient.
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