Originally Posted by kero
Interestingly enough, my 2.5i wagon on 87 knocks or pings alot. I changed over to 93 and it doesn't happen. When I am tight on money and go back to 87, the pings/knocks start again.
The gas station or company has no affect, it's the octane for my car that makes the difference and I haven't read much about others having the same issue.
With the A/C, I have to 93 or my car cries like a baby.
What I said earlier plus
Octane does not slow flame speed; it simply delays the initial combustion
so a lower octane fuel used does not delay initial combustion and the excess carbon in the combustion chamber might create hot spots causing pre ignition which goes away when you use the higher octane fuel. Did your buddy change the oil frequently?