In Reply to: Re: And which one is the best ##W-## for M3s?? (eo posted by Pete on January 09, 2000 at 08:52:32:
Yes, some oil companies like Redline, Valvoline, etc. sell special racing oils (20w, 30w, 40, 50w, and 60w) This isn't too thick if you were doing some high performance racing. For starting, yes it is thick since it may act like syrup. Thats why engine priming is necessary. If you put 0w-30 in your M3 engine and went road racing for 3hrs straight for 2 days, the polymers in the engine oil will start to break down (cause of excessive heat) and will turn into it's base weight (0w). Now you don't want 0w oil lubricating your engine at normal or above operating temp. You can use 5w or 10w for starting but once your engine goes to normal operating temp. It may want something like 40w or 50w.
The only difference with racing oils and regular synthetic is that it has additives to keep it from foaming. However there aren't enough or any additives in racing oil to remove sludge or attack harmful particles.
I would use 15w-50 or 20w-50 for track use, forced induction, N20, stroker, or any mods that increase combustion temps. Heck I use 20w-50 in city and I didn't notice anything.
Using BMW 5w-40 now.