Regular, mid-grade, or premium?

[curtistuckr]

What grade of gasoline should I put in the tank?

curtistuckr -- 1987 BMW 635CSi (E24) -- Savannah GA

[Pabloel]

From my expierience BP 93 octane has the lowest amount of sulfur. Cleared CEL on my oxygen sensors on the 528i e39 which was a big lol for me!

[Der Krieger]

My M30s have always been perfectly delighted with a middle grade; although they don't complain over regular, either ...

[oxen]

these cars have no knock sensor. so they dont realy care as the timing is not super agressive on these old cars. but i like to burn 92 oct , but 87 is just fine. its up to diver decision what you feed your car :)

[vadon]

+1 with oxen.I have a preference for shell or BP premium.

[volac]

I've always put premium in, due to my dinan chip. You just get used to it, but I bet it's cost me a lot of money by now over regular :P

[bgriff]

My '85 also has a Dinan chip - at first I used hi octane because Steve Dinan recommended it, a few years ago I started stepping it down to 89, then 87 - now I only use regular (87) in it and the car runs great. I've used regular in my '79 since it was new, have had no problems yet.


Bob G

[tlister67]

I use premium (91) from Chevron. I might try a local supplier in town that is ethanol free.

[CW6er]

The book calls for 87 octane. It is a waste of money to use anything higher unless you have chipped the car. The engine does not produce any more power by using a higher octane. Actually, the higher the octane, the less volatile the fuel is.

Back in the bad old days ('80's to mid '90's), the gas had too much sulfur in the gas for the fuel injectors and injector cleaners were developed to help. Then Chevron/Standard started blending their Techron cleaner into their Premium and then Mid-grade fuels and others followed suit. I used the Mid-grade Chevron for several years and it did make a difference when the sulfur levels were high, and people got in the habit of using Premium/Mid-Grade because they could feel the diffrence. But now, by law, the sulfur levels have been reduced and are no longer a big problem. Either a can of Techron or a tank full of gas with a blended cleaner once in a while is all that is needed.