[bluesubie]

Originally Posted by viscositosis.rex

Noack. Pennzoil Ultra is GF5. Pennzoil Ultra has a Noack approaching Red Line or Amsoil. Pennzoil Ultra Platinum is moving toward GF6. It has a higher Noack.
I say Noack is overrated-just like many used to say viscosity index is overrated. The Noack test is conducted at a very high temperature. It is not necessarily indicative of engine cleanliness.
Oils of the future will be thin. They will have high quality, moderately expensive base stocks. Additive packages will not need to be so robust. The key question will be how long before they shear beyond acceptable levels. Just one man's opinion.

Have read in recent times that Noack is :
* meaningless, as your engine oil never gets to 250C and sits there for an hour (multiple times);
* not relevant for xW-20 oils as they run so cool;
* not relevant as catch can deposits are oil mist, not light hydrocarbons.

Major problem with all of these arguments is that volatility tests are there to assess the behaviours of oil that's left above the top ring, hot, and washed by air/gas flow within the cylinder.

These films, and the vapours that are released have direct access to the catalyst on the exhaust stroke, and therefore have relevance, particularly for emissions system performance.

http://www.bobistheoilguy.com/forums...ingless..._???

-Dennis