I agree with Terry 100% on this one ....
Manufacturers viscosity/temp recommendations are typically based on the use of average and even below average quality lubes. I've been running 5w-30/10w-30 and now 0w-30 synthetics in VW/Audi engines for 18 years and approx 400k total miles with excellent results. Five years of these years were spent in the CA desert near Edwards AFB and the last thirteen have been in Georgia and Alabama. My thinking was that the low viscosity synlube would run cooler and be more stable under high temp/high shear rate conditions. So you could go one SAE grade thinner than what was recommended with conventional oils. It turns out this works exactly as predicted ....
The oil pressure gauge in my Audi 100 would peg the needle @ 5 bar/74 psi with the Amsoil 10w-30 synthetic at anything over 3000 rpms. Oil pressure much higher than that is wasted, as the oil pressure relief valve in the engine will open and shunt oil back to the pan.
Up until several years ago, a 15w-40 conventional oil was the thinnest viscosity German manufacturers would recommend for hot weather use. Porsche was the first to deviate from this and started producing a second viscosity/temp chart for synthetics in the late 1990's. It' allowed the use of 5w-30 and 10w-30 synthetics for year round use - even in the air cooled 911 engines. Other German manufacturers have followed suit and now 5w-30 and 5w-40, ACEA "A3/B4" quality oils are the most widely specified grades, followed by 0w-30 and 0w-40. My 2002 Audi TT turbo recommends 0w-30 year round, regardless of climate, with 5w-30 and 5w-40 as acceptable options. The current BMW viscosity recommendations look like this:
General: Synthetic oil meeting BMW "Longlife" specifications.
Above -5F: 10w-30/10w-40
All Temps: 0w-20/0w-30/0w-40/5w-20/5w-30/5w-40
If you run the Redline 5w-30 or 10w-30 in your Audi, you'll see about the same oil pressure you do with the M1, 0w-40. The reason is that the high temp/high shear viscosities of these oils is about the same. Towards the end of the drain interval, I'd actually expect the oil pressure with the 5w-30/10w-30 Redline to be a bit higher, since it's very shear stable ....
TooSlick
Manufacturers viscosity/temp recommendations are typically based on the use of average and even below average quality lubes. I've been running 5w-30/10w-30 and now 0w-30 synthetics in VW/Audi engines for 18 years and approx 400k total miles with excellent results. Five years of these years were spent in the CA desert near Edwards AFB and the last thirteen have been in Georgia and Alabama. My thinking was that the low viscosity synlube would run cooler and be more stable under high temp/high shear rate conditions. So you could go one SAE grade thinner than what was recommended with conventional oils. It turns out this works exactly as predicted ....
The oil pressure gauge in my Audi 100 would peg the needle @ 5 bar/74 psi with the Amsoil 10w-30 synthetic at anything over 3000 rpms. Oil pressure much higher than that is wasted, as the oil pressure relief valve in the engine will open and shunt oil back to the pan.
Up until several years ago, a 15w-40 conventional oil was the thinnest viscosity German manufacturers would recommend for hot weather use. Porsche was the first to deviate from this and started producing a second viscosity/temp chart for synthetics in the late 1990's. It' allowed the use of 5w-30 and 10w-30 synthetics for year round use - even in the air cooled 911 engines. Other German manufacturers have followed suit and now 5w-30 and 5w-40, ACEA "A3/B4" quality oils are the most widely specified grades, followed by 0w-30 and 0w-40. My 2002 Audi TT turbo recommends 0w-30 year round, regardless of climate, with 5w-30 and 5w-40 as acceptable options. The current BMW viscosity recommendations look like this:
General: Synthetic oil meeting BMW "Longlife" specifications.
Above -5F: 10w-30/10w-40
All Temps: 0w-20/0w-30/0w-40/5w-20/5w-30/5w-40
If you run the Redline 5w-30 or 10w-30 in your Audi, you'll see about the same oil pressure you do with the M1, 0w-40. The reason is that the high temp/high shear viscosities of these oils is about the same. Towards the end of the drain interval, I'd actually expect the oil pressure with the 5w-30/10w-30 Redline to be a bit higher, since it's very shear stable ....
TooSlick
