better than your average gas...

[Justin99GST]

i just got a 99 GST, got a little tired of having to fill up my trans-am every two or three days. the question i have is about higher octane gas like 100, 105, 110 for instance. i currently live in Wa and go out to SIR or pacific raceways whatever you choose to call it and they have their own gas pump with the three above listed choices of gas. will running any of them hurt the car, suprisingly i found the GST completely untouched and will begin modding soon, this was just a question i was curious about. thanks in advance for the help.

 

[chromegsx]

The higher the octane number the more resistant the gas is to detonation (very bad for your engine) The higher the number does not mean better gas mileage and in some cases gas mileage may be improved by lowering the octane you normally use. If the car is un-modded just use regular gas and don't waste your money that you can use on mods. But in the end it shouldn't "hurt" the car as long as it is not LEADED. If it is it will kill your O2 sensor shortly and you will definitely get bad gas mileage.

 

[weith1111]

edit: ^^^^^^ beat me to it!

Unleaded high octane will not hurt anything, but leaded fuel will destroy the o2 sensor(s) and cat over time. Meaning using them on occasion, but not at every fill up, would be ok. The only downside is, unless you have some means of tuning, using race gas will not improve anything for you, and actually may make power/gas mileage worse. That's a quick answer, there are tons of threads on this, just search for race gas or 100 octane or leaded fuel.

 

[Justin99GST]

i was only intending on playing with it a little bit at the track like maybe a 1/4 tank or something, i dont want to spend the money to use it on the street. i hadnt planned on really using it until i get somethings for the car, i was looking at the greddy profec-b II or the e-manage havent decided yet. my buddy has a GS with a turbo kit on it and knows a thing or two about cars so i am kinda depending on him since i have never owned an import not to mention a turbo charged car. thanks.