I have reprints of actual dyno results of the Amsoil Series 2000, 20w-50 from testing done on 358 ci, 400-525 Hp, Winston Cup and Busch Series racing motors. Most of these are from 1995-1996, when the S2000 was first introduced and show a gain of 2-4 Hp over other racing oils. I have no doubt that Amsoil is used in these cars, although it's more likely to be the 0w-30 and not the 20w-50 these days.
The change from 20w-50 to 0w-30 and even 0w-20 has occurred in the past 6-7 years. Running low vis oils allows you to avoid one refueling stop in a 500 mile race, so it's a huge tactical advantage ....That's why everyone runs the thin oils these days, that and about 10-12 more horsepower at the high end.
[ December 19, 2003, 01:18 PM: Message edited by: TooSlick ]
The change from 20w-50 to 0w-30 and even 0w-20 has occurred in the past 6-7 years. Running low vis oils allows you to avoid one refueling stop in a 500 mile race, so it's a huge tactical advantage ....That's why everyone runs the thin oils these days, that and about 10-12 more horsepower at the high end.
[ December 19, 2003, 01:18 PM: Message edited by: TooSlick ]