Regular vs. Premium

[kjewer1]

Higher octane tends to burn slower. But the burnrates are actually very close. It is more accurate to say it doesnt ignite as easily. BUt this is a very complicated subject, and I could go on for another novel here...

Changing plugs shouldnt affect mileage unless you didnt gap them properly. Gap can affect economy for sure.

Edit> Its also worth noting that how the car runs on 87 depends on the car. In my case, if someone acccidently put 87 in my tank I would lose the motor, no question in my mind. And it has happened to other people with well modded cars. One guy lost his motor when his GF tried to be nice and fill his tank for him after borrowing the car. I feel bad for both of them. Thats one reason I only run premium and I make a big deal about it so anyone that could potentially use my car doesnt make the same mistake. Its also nice to have things like DSMlink that warn you when you are kncking, even when you are not datalogging (CEL comes on at over 3 degrees of knock retard).

[fussman238]

Thanks guys great info you've convinced me to use premium, after i thought about it 2-3 dollars a tank is nuthin to worry about haha thank god for AF.com