Originally Posted by wmandra
oil temps have been rock solid on mine, even when pushing hard on the track. 2 days at watkins glen and temps never went above 250F. I've actually considered installing the auxiliary radiator that comes on the N20 in the X3, but held off. I may log water temps when I go to Limerock next month and see what they look like. I think there may be something to what you were saying about better cooling in the engine bay, the Z4 bay is significantly larger than the 3-series.
It has better air flow from the kidneys, too. In the oil cooler thread we had going before, someone (was it you, Nick?) mentioned dropping in the radiator fan from the 335is or 1M, which should be PnP for our cars (at least on the N54). That would help on an N54 car.
Nick, I bet you would see oil temps drop a lot if you threw some catless downpipes on there. I know you're reluctant to do invasive bolt-ons due to warranty issues and understand your concern, but I'm just mentioning this as a theoretical matter. I saw oil temps drop on my Mini with the N18 when I put a downpipe on there.