I run 87 octane in mine with no problems. That's also what my owners manual says to put in it.

This is the best explaination I have seen on Octane. Very informative
http://auto.howstuffworks.com/question90.htm
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Paul NW Indiana '89 740 Turbo 110,000

I am running with premium myself, I just don't feel like taking chances especially when it starts to get hot again down here in FL.


And yes, on the warm up/shutdown question, yes, definitely let your car warm up to normal operating temperature before you start slamming on the gas pedal. I usually let my car idle for a minute or two before I head out and I take it easy until the temp needle starts to rise. When shutting down, you'll want to let it idle for at least 30-60 seconds before switching the engine off depending on how hard it was driven. You have a water cooled turbo which doesn't require the 2min+ cool off times it takes for oil cooled units.


-M.R.

I don't have problems with pinging.
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Norm Cook Vancouver BC; 1989 745T 204,000KM

I'v always run 87 octane in my '89 but it does tend to miss a little if I'm going up a long hill or getting on the turbo quickly. Higher octane would help but I feel you don't really need it.

I run the cheap stuff in my 940t when the weather is mild to cool for highway type driving, but if runing in the mountains or when the weather gets hot I step the octane up accordingly. It'll tell me if the gas is too cheap ( ping )
Doesn't hurt to warm it up a touch ( spinning something cold at a few zillion rpms can't be good ) and yes, a cool down for about 30 seconds in a good idea ( unless of course you've already been idling through a parking lot for more than that looking for a space :-)
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '82 Mercedes 300SD for sale