Originally Posted by
hahnmgh63
Audi say's a synthetic 5W-40 meeting VW spec 505.01. I use Redline 10W-40 which has the highest HTHS (High Temp High Shear) rating of any 10W-40 oil out there, at least from the manufacturers that are willing to test or post it. The Redline 5W-40 is also one of the best for HTHS which is one a required test for the Euro ACEA ratings to meet certain grades. The best Mobil 1 is the 0W-40 (In N. America) and it only has a HTHS of 3.6 whereas Redline 5W-40 has a HTHS of 4.6 (10W-40 is 4.7). Redline also has one of the highest ZDDP contents out there. I won't go into the need of ZDDP (Zinc dialkyldithiophosphates) which was reduced in oil sold in N. America by the EPA so for the first time in history, the quality of our oil decreased a few years ago.
I won't knock everyone else's choice as there are many good oils out there, I just think Redline is one of the best if not the best.