Race Gas - Fuel 101

If the engine in your car has a compression ratio greater than 11:1 and routinely sees sustained rpm levels over 6,000, you have a candidate for racing fuel. If you have an engine that was assembled by a professional engine builder, you should be using the fuel that the engine builder recommends. The real issue with the use of racing fuel, aside from the needs of a high-compression engine, is the elimination of the variation seen in gasoline purchased from the corner gas station, such as octane levels, specific gravity, and vapor pressure.

For those of you who use alcohol for fuel, the difficulties you face are based on series or class rules. When I use the term alcohol, I am talking about methanol. The issues with alcohol are related to storage methods and the impact the fuel has on the engine, fuel systems, and fuel system components from a corrosion perspective. Alcohol is hygroscopic, which means that it will absorb water from the air. The containers used to store alcohol need to be kept air tight. The entire fuel system needs to be serviced on a more frequent schedule than a car powered with gasoline. Many rubbers and metals within the fuel system require more frequent replacement due to alcohol's hygroscopic nature.

There are different grades of alcohol available. You can get methanol that is pure and has a water content of less than 1 percent. While this may not sound like a significant percentage, remember that the alcohol you get at the track may have been exposed to the air longer and is more likely to become contaminated than alcohol that has a guarantee of purity. This level of purity is very expensive because a great deal of care has been taken. You may not even be able to tell the difference in how your car runs.

The transportation and transfer of fuels is something that many racers give little thought. The containers used to transport any gasoline need to be UV proof. The ultraviolet rays in sunlight can break down gasoline. In fact, some racing gasolines can undergo very serious degradation when exposed to sunlight. The container should be either metal or plastic and designed for the transportation of gasoline. If the container is plastic, then one of the best colors to use is black. If you can see the level of the fuel in the container, it is too translucent. Alcohol fuels are not as sensitive to sunlight exposure. Just keep the lids closed to minimize any exposure to the air. This is even more critical in humid conditions.

Another thing you need to remember is the hissing you hear each time you open a can of gasoline is the sound of all the light components of the gas escaping into the atmosphere. You want those light components. Granted, you will not be able to eliminate the escape of some of the light components when you open a container, but there are ways to minimize the escape, so open the can as little as possible. Do not let the fuel can sit in direct sunlight; keep containers in the shade or throw a towel or tarp over them. I have seen plastic cans swell up like balloons after sitting in the sun for a couple of hours. Remember, sunlight is an enemy of gasoline, so do your best to keep the gas cans out of it. This is something you can do to improve quality and reduce the variation in your fuel for free. There's not much you can do in racing that is free of charge and improves performance.

The reality for the Saturday night racer is that there are no pit stops, so fueling the car does not have to be accomplished in 12.5 seconds under the pressure of the race. We have some time to make it happen.

The trick is to keep the fuel clean as it is transferred to the tank. This involves several steps. First, make sure the can is clean prior to putting in any fuel. This includes the inside and the outside of the container. If the outside of the can is dirty, there is always a chance of the dirt or debris falling off the can and into the funnel or the tank. Use a good-sized funnel that is equipped with a filter. You can get some great disposable filters at any automotive paint supplier that are cheap and fit well into the oversized funnel you should be using to fuel your car.

For any of you considering the use of aero gasoline or aviation gasoline, this is fuel designed for use in a piston-powered aircraft, so please just forget about it. It is illegal to pump this fuel into anything that is not an airplane, and the fines are quite high. Aviation fuel was designed for engines that run very low rpm, and most race engines idle faster than airplane engines run at cruise speeds. The chemical makeup is also wrong for the type of engines we use in race cars, so aviation fuel is not even a consideration. It will cause more trouble and there is no upshot to using aviation gas.

Remember, keep the fuel clean, keep it in the shade, and don't spend more for it than you need to. It is just that simple.