5W-20 and 0W-20 - why not in turbocharged engines?

[Michael_P]

AE
Have you noticed oil pressures before and after (20 vs, 40). The more journals, galleries, bearings and other various oil passages such as turbo bearings, the more there is a chance to have a drop in oil pressure. Granted engines of this sort have pumps to compensate for such passages.

 

[AEHaas]

Yes, pressures go down. But in all cases, the pressures are about 60 PSI at 4,000 RPM with the lower viscosity oils at normal operating temperatures driven around town and on the highway.

aehaas

 

[CATERHAM]

Originally Posted By: AEHaas
I use 20 grade oils in the Maybach 57s AMG and Bentley GTC (update: traded in on a 2011 Flying Spur Speed a month ago). Oil analysis showed normal wear and tear in these engines running around the 600 BHP mark. Both of these are twin turbos.
The Enzo (650 BHP) running a 0W-30 oil (10W-60 spec'ed) shows less than 1/2 the wear of my next door neighbor's car run under the exact same conditions using the OEM oil.
aehaas

What Dr. Haas fails to mention is that the RLI 0W-20 bio-ester based oil he runs has a HTHSV equal or greater to 2.95cP which is more typical of a light 30wt oil.
And for the Enzo the RLI 0W-30 has a HTHSV in the 3.6cP-3.8cP range, again more typical of a light 40wt oil.