How do You Fill?

[Herr Faust Schinken]

Stock ecu 17lbs injectors (po installed them) and I fill up on 91 don't have idle issues get 1-2 better mpgs on average it seems

[mikeedler]

the cheapest stuff out there, and on occasion, I pump some of the Diesel/gasoline that we pump out of diesel cars that fill up the incorrect fuel. I try to mix that 30% crap mix to 70% cheapest............. car runs a bit like crap sometimes, but it saves me about $40 per tank.

[salvuhdor]

Mine takes nothing but 91 gas. V power from shell. 1991 318is m42

[Hooffenstein HD]

98 RON(93 AKI). Stock B23 with long tube headers.

[mrsleeve]

I buy diesel

[kway]

I used to be die hard "premium fuel only". Then I bought a DD '90 325i (stock ecu) that would throw a check engine light at the same spot on my commute every time (bottom of a long hill) and would go out after a minute or two. Never even bothered to stomp test it.

I filled up on 89 one time, don't remember why, and no more CEL. I fed that car 89 from that point on until the end of it's life, and both of my DD e30s since with no issues.

[slammin.e28]

For the e28s (B34 and B35 respectivly) and Rover (M52) it's 87 non-ethanol, or 89 Shell/BP.

E46 and M3 get 93 non-ethanol or 93 Shell only. Of course if I'm in a pinch I'll deviate, but I'll never buy gas from Sheetz, WaWa, or 1970 retro mom and pop rape stations. I work like 5 miles from Southern States, who sell non-ethanol, and the (curvyyyy) road next to it goes directly to my house, pretty much, so I make it an on the way home thing.

[InuFaye]

93 octane in everything thats not the 328i, that gets 89.

I just use the cheapest shit I can find, there is no difference in the ethanol gas.

[fronton]

I fill very carefully so as not to drip on the paint. 93 only for the MarkD chipped s38

[unevolved]

89, because M42.

[slammin.e28]

...there is no difference in the ethanol gas.

I respectfully disagree.

That is all.

[jlevie]

The required octane is determined by the compression ratio. The compression ratio of M10 and M20 engines is below 9:1, which means 87 octane (just like the owner's manual says) unless it has been chipped to require 91-93. The stock DME's spark timing isn't advanced enough to properly use greater than 87 (higher octane fuel burns slower).

[InuFaye]

Aint no difference dawg.

[ForcedFirebird]

The required octane is determined by the compression ratio. The compression ratio of M10 and M20 engines is below 9:1, which means 87 octane (just like the owner's manual says) unless it has been chipped to require 91-93. The stock DME's spark timing isn't advanced enough to properly use greater than 87 (higher octane fuel burns slower).

I have experimented with timing and octane and don't see why the m20 with chips need premium unless they are pulling that much fuel and making them run lean. Keeping fuel ratios in the 12's when flat out, 87 has never knocked after we tuned a car.

[Holland]

I usually put the fuel filler in the filler neck before I pump...

Wait what?