Originally posted by Big Jim:
Well I guess I'll jump in here with both feet. Again. I've posted about this before.
I use 87 octane in my 98 SVT E0.
With 136,000 miles on it it has had only about a dozen tanks of 91+ octane in it. I can find no difference in MPG or performance. And I often (if not nearly always) drive in a very spirited manner.
Have I ever heard any detonation? Yes, three times. All three times on hot winter days (we have some of those in Southern California). So that would have been with winter blend fuel. It was also only present at light to moderate throttle acceleration. It was very mild, what may be called a "trace ping". It went away with hard acceleration (richer fuel mixture) and at constant load and speed.
With that said, I also meticulously maintain the engine including the fuel system. The air filter is changed every 15,000 miles. The throttle body is cleaned often, at least every 10,000 miles. The oil is changed every 3,000 miles. Injector cleaner is added to the fuel with every throttle body cleaning. All this to minimize the carbon build up in the cylinders and ports and to keep the injectors free flowing. If I felt for a moment that I was harming the engine I would use higher octane fuel. Others may not be able to keep such a close eye and ear on their engine.
Octane is nothing more than a measure of the fuels ability to resist ping. It does not in and of itself create more power. Other things that inhanse power may make the slower burning higher octane fuel necessary. If you don't need the extra octane you are just paying extra for something you don't need.
So I'm not saying that this is for all SVT owners, but it works for me.
There is a article that was posted in the forums that would show you different.
