Anybody wth an M20 525i...

[CharlesAFerg]

oops

[CharlesAFerg]

I saw some old people filling up their chrystler something (old people car, I don't even remember) with rpemium, I'm beginning to think that people thing premium is better for the engine because it's called premium... The only car I get premium for is the family's Porsche 928s They are picky, because it was built for it. I was just curious if the E34 was built for higher octane, but i figured not, just thought I would check!
Thanks guys

[TheEndIsNear]

The book for my '90 says regular is fine but I run 3 out of 5 tanks premium. I never notice much difference in power or mileage but I do get slightly more tick on the regular.

[SC David]

My car runs noticeably worse with regular. Idle will be rough and there is a loss of power. My girlfriend's E30 M20 runs smoothly with regular though. Meh.

[TheEndIsNear]

I really think it just depends on how beat the motor is and how honest the gas station is...

[BillionPa]

any car with a "performance chip" should require high octane gas, because the performance chips mainly change the timing advancement maps.

however, running high octane on a car that is listed for low octane can actually cause problems, because octane is the resistance to ignition (and preignition), and having the gas ignite at a different speed is bad, mkay

[TheEndIsNear]

Well said... My protege always ran better on regular.