Does Premium Gas Give More Horsepower?

Vehicle maintenance plays a big part in fuel economy and performance, but there are also other ways to achieve this. Using fuel with the correct octane rating is essential. The use of different fuels can change how your vehicle drives and can have other added benefits.

Gasoline comes from the refining process of crude oil. Crude oil is heated to a specific temperature and the gases that result are then distilled and cooled into gasoline. After the gasoline is produced, then fuel manufacturers add their own additives to it.

Internal Combustion

The internal combustion engine works off the same principals as just about every engine. A combination of air and fuel is pulled into the engine during the intake stroke. The mixture is then squeezed during the compression stroke. The mixture is then ignited with a spark during the power stroke. In a properly functioning engine, the ignited fuel will burn evenly in one direction. The wasted gases are then expelled from the engine during the exhaust stroke. The variables that effect the engines efficiency and performance are how much air and fuel the engine can can bring in and expel and how much it can compress it during the compression stroke.

A high-compression engine will squeeze the air and fuel into a tighter area than a low-compression engine will. The more the mixture is squeezed, the more power the ignited fuels will create. The higher the compression, the sooner the ignition must take place. This is one of the variables used in calculating the ignition timing of the engine. The sooner the ignition takes place, the slower the fuel needs to burn. If all of this does not happen correctly then serious engine noises and damage may occur.

Spark knock and detonation are noises you hear while the engine is running, particularly under acceleration, if the fuel is ignited at the wrong time or burns at the wrong speed. This can be caused by a bad engine sensor, an internal engine problem, or even the wrong fuel. This will cause serious engine problems and can result in engine failure.

Octane Rating

Octane rating is a number that indicates the fuel’s resistance to spark knock or detonation. All fuels have approximately the same amount of energy when burnt in the engine, but the octane rating is what tells you how controlled the burn is. The higher the octane rating, the slower the fuel burns. Fuel manufacturers increase the octane rating of gasoline by adding in hydrocarbons such as ethanol alcohol to slow down the burn rate of the fuel. In general, the higher the octane rating, the slower, more controllable the fuel burn is.

Engines are built to produce a specific amount of horsepower and torque. They must also be efficient and achieve a good fuel mileage rating. The compression ratio of the engine and the amount of air and fuel that is used has a direct impact on these ratings. Manufacturers will recommend the octane rating that your engine is designed to use to allow it to reach those power and mpg goals. This octane rating is also programmed into the vehicle’s computer to allow it to make calculations and adjustments to ignition timing. Sensors, like the knock sensor, are used as inputs to tell the computer that something is not right and that the wrong fuel may be in use. The vehicle’s computer will make adjustments to the engine as necessary.

Bottom Line

Higher octane fuels will not produce more power in a low-compression engine that is designed for low-octane fuels. But if you use a low-octane fuel in a high-compression engine, the performance of the engine will suffer. The vehicle’s computer will typically adjust ignition and valve timing to compensate for the lower octane fuel, which in turn will decrease horsepower. This can also decrease fuel mileage in performance vehicle. Using the recommended octane fuel is essential in achieving the power and mileage that your engine was designed for. This will also keep you from wasting money on higher octane fuels that do not provide any benefit to your vehicle.