Inherent advantages of a Grp1 vs a Grp 2 oil?

[FCD]

Are there any inherent advantages of a Group II over a Group I base stock?

 

[Shannow]

Group II has a higher Viscosity Index, and better resistance to oxidation.

Group 1 has a slightly better ability to dissolve stuff like additives and varnish.

 

[FCD]

But overall a Group II is better isn't it, a Group II with a good detergent additive package would probably be able to keep an engine cleaner than a Group I with less detergents correct?

 

[Joe90_guy]

It's easiest to think of Group II base oil as Group I that's been treated with hydrogen to neutralise a lot of the nasties which cause base oil to react with oxygen. It might make it last a bit longer in your engine but it won't necessarily make your engine ant cleaner.

The big advantage for base oil producers is that Group II is inherently cheaper to produce than Group I. For a given amount of raw Vacuum Gasoil feed, you get a higher yield of usable base oil. The only downside is that the process tends to destroy heavy base oil and create light base oil (something you see with Group III's too but far more pronounced).

 

[JHZR2]

Group II is better overall because of its VI and oxidation resistance. Group I is still blended for cleaning and solubility reasons sometimes.

 

[FCD]

yeah now i'm running Shell HX3 which is a dual rated high mileage group 1 oil, and the oil does seem to have gotten dark faster than before, which would i guess indicate cleaning

 

[Popsy]

Now you have to try VR1 20W50 and after that compare with VR1 5W50, gr II vs gr III+

I'm not sure the darkening of the HX3 has 100% to do with cleaning, in the same engine I've seen some oils becomming darker than other. BTW, in my pre-bitog days I tried HX3 and my engine didn'tliked it, not sure it this oil is still good enough now.

 

[FCD]

Sure will, in a couple of years i will probably go to Finland with the Capri during the winter which would be the perfect excuse to try out VR1 5w50