Does fuel grade really make a difference?

Question

Does fuel grade really make a difference?

Answer 1

Yes but new cars are designed to run well on 87.  I drive a 5000 lb truck and 87 is fine. Older vehicles are where you can really tell the difference.  I have an old truck too, with a 35 year old V8 in it, and it runs much smoother and cleaner on 93.

Answer 2

It does for some cars. Some are set to run better on premium. Our motorcycle runs better on high test. Out classic Mercedes takes premium. The van , it does not matter. However, the gas with alcohol we have now is working worse an getting lower gas mileage.

Answer 3

It's funny - the grade of the fuel is a measure of the octane in it, and octane is actually a flame retardant.  It means that a high-compression engine needs high-octane gas to run without destroying itself, but adding octane actually reduces the amount of power that gas can provide.  Modern engines have computers that can accept the low octane, more-dangerous gas, and run without destroying itself.  Older engines, especially high-performance ones without computers (like old musclecars) need high-octane gas to stop them from burning out the pistons while still providing high horsepower.

So, yes, fuel grade makes a difference.  If you have a modern fuel-injected computer-controlled car, use the low octane, cheaper fuel.  If you use higher grade fuel, you are reducing your car's power for no reason.