GF-5 & Viscosity Modifiers

[buster]

Quote:
Another change associated with API SN/ILSAC GF-5 oils will be greater fuel economy performance. This improvement in fuel economy will be achieved by increased use of polymers called Viscosity Modifiers. These polymers help a “thin” oil act “thicker” under low stress conditions. While the liberal use of polymers helps improve fuel economy in modern passenger car engines, older style push-rod and race engines produce greater shear stresses that can “tear” these polymers. When these polymers are sheared, oil losses viscosity, and that can lead to increased wear.


One of the benefits of GF-5 will be increased fuel efficiency. I've heard from multiple sources that a lot of this will be achieved through viscosity modifiers. I wonder if we will see more shearing with some of the GF-5/SN oils?

 

[modularv8]

I thought it was primarily friction modifiers. What is interesting is that the new piston deposit spec will require more detergents that will supposedly compete with friction modifiers.

"Detergents are used to prevent piston deposit build-up, but trade off exists between increased Piston Cleanliness and Fuel Economy. The detergent components that go the metal surfaces to keep the engine's parts clean compete against the friction modifier components that go to the metal surfaces to reduce friction and improve fuel economy."

http://www.gf-5.com/the_story/performance/

But increasing the amount of viscosity modifiers also does improve fuel economy but depends SAE grade.

BTW, maybe explains the higher amount of Boron in Pennzoil Ultra as a nonferrous passivator since Pennzoil Ultra is a high detergent oil.

 

[Tempest]

More plastic in my engine...great.

 

[buster]

Good points modular. All things considered, it sounds like Pennzoil has a really good formulation going if they are meeting GF-5 FE spec and claiming superior Seq IIIG results. Pennzoil did say they believe they created a new standard.

 

[buster]

Surprised more folks are jumping on this one.