In Reply to: Very well stated Bob posted by Don Stevens on September 12, 2000 at 19:53:22:
You have obviously done some homework. I use Amsoil 20W50 in my track car (in Florida) for a couple of reasons. 1) I just can't shake the thicker is better old school thinking for the real extreme temps we get at Sebring (I have seen 250F on my gauge). I know this is kind of dumb but I have yet to try the 0W30 on the dyno to prove to myself that I am giving up any power. 2) I like the extra zinc and phosphorous the 20W50 has.
Regarding the other gentleman's comments about 5W40 am 10W50. There is more to be lost than gained with these oils. First, I believe these are Syntec blends which, in the US, aren't even in true PAO synthetics. They are better than most petros but they are in a completely different clasification of base oil than Amsoil and Mobil. Second, any oil that has a viscosity spread of more than 30 points is using a viscosity modifier to get the extra spread. The VM breaks down faster than the base oil (particularly in track conitions) and eventually causes the oil to behave like a straight 25 or 30 wt oil. The cold start beneifit you originally bought the oil for is essentially gone by the time your drain interval is reached. In this scenario the 0W30 is better for your car per Bob's argument.
The point is, if you are using your car on the track, use the best like Bob does.