which grade of gas do u use?

[China Man]

sunoco 94 octane

[GMGX5]

BMW DME'S are smart enough to know what octane you are running and with back off timing etc. to match. Might not ping but definately will lack a little preformance.

[bimmerFanatic]

Highest they sell in Cali is 91.

[xxx]

94 Toronto

[Eurosport]

92 chevron (close to the house, newer gas station=clean tanks=less chance of crap in your car)

[vinuneuro]

These engines have high compression= higher octane fuel required. 91/93.

[Schanck]

V-Racing 100 Octane 5% Ethanol from Shell

Melbourne Australia


Schanck

[Tupps11]

We have 98 and 95 here in Lebanon (keep in mind its RON)

The US uses a different scale AKI which converts as follows...

98 RON = 95 AKI
95 RON = 91 AKI

I always put 98 premium in all my BMW's. You should too

[JCL]

98 RON (Research Octane) as usually used in Europe = about 92 Pump Octane in North America (calculated as (R+M)/2, and also called AKI for anti-knock index) - and it is not a mathematical conversion as the test methodology is not the same for the research and motor methods of measuring resistance to pinging. It is usually about 5 or 6 points.

Using lower quality fuel will not result in pinging on the BMW engines as long as the DME can modify timing sufficiently. Taking it to extremes is obviously not recommended. I have never heard pinging on my 3 vehicles on my local 87 or 89, but performance and mileage both suffer on 87 due to the timing being retarded. I have absolutely no performance or fuel consumption degradation on 89, but that is my local 89. Fuel quality will vary widely with geography, which is why BMW specifies 91, to cover the areas that are on the low side. In other areas of North America 89 may definitely cause a performance degradation.

[4.8ISInCanada]

Originally Posted by Quicksilver

Mr. Wattenburg and others will also tell you that your fuel milage will suffer also.

Well, I've never heard him actually say that. He has said you might have a slight difference in emissions which is why they tell you to use Premium in the first place. He has said if you drive your race car 160MPH and switch to premium you might get 166MPH out of it.

Actually on Sunday night/Monday morning a caller specifically asked him about running regular in a BMW and rather than me paraphrase it anyone that wants to hear can download it here:

www.drbill.org

grab OpenLine2006-11-12.mp3

Its 30MB (fast download speed though) because its a 3 hour show, but the BMW fuel question comes up at precisely 2:47:58 so you don't need to listen to it all.