What octane of gas would you put in a 535i

[winfred]

around here it's only a extra buck or two to tank up on 93* instead of 87* so if the car likes it after a tank it's not a big deal, i need to run 93* because i have chips in my cars but i can't remember running the cheep stuff because the last several cars i have had have ether needed preimum or could of atleast used it's benifits (turbo volvos with the boost turned up)

[Kalevera]

Are you sure someone didn't pull a coding chip change on the car?!

best, whit

[Nick.Hay]

I'm not sure if I want to know HOW you found that out!!

[Dash01]

FWIW, I've recently run both regular and premium in my chipped '90 535i: Seat of the pants, the car seems to run smoother and somewhat peppier with premium, and gets better fuel economy on the highway cruising at ~75-80 mph.

The better mileage pretty much offsets the higher price for premium fuel, so cost per mile works out about the same, with somewhat more pep.

[Jay 535i]

Keep in mind that different countries measure octane differently. An octane 'rating' of 91 isn't necessarily the same everywhere. You want to know how that number was arrived at.