BruceH

.......

SuperHoss

Group 3 base stocks still hold paraffin wax which is a possible build up problem (if you do not change your oil properly). Group 4 bases have an advantage in extreme conditions...extreme meaning hotter than average weather, very cold weather, or very harsh driving conditions (stop-and-go traffic). Very cold weather will cause Group 2 and 3 stocks to start forming waxes and will "freeze up" sooner than Group 4 bases will.

Honestly, if a person is not in any extreme conditions then synthetic will not be a great benefit to them. Group 3 "synthetics" are highly refined but they still carry a small amount of impurities.

Edit - Group 4 bases will not form waxes in extremely cold weather, they will "freeze up" at a lower temperature than Group 3 bases.

Unleashedbeast

Bruce, you are right on so far. Allow me to add some things.

The only advantage I have ever read about, that group III is superior to a group IV, is solvency. Supposedly, group III base stocks hold contaminants in suspension better than group IV.

but what does that matter? Esters mixed with PAOs do the same thing. Redundancy......

Other than that, group IV wins in every other classification.

1. Superior cold pour properties.
2. Superior NOACK Volatility (burn off at high temperatures)
3. Superior HT/HS (High Temp / High Shear)
4. Superior oxidation resistance
5. Superior anti-friction characteristics (uniform molecules - no impurities)

Basically, when you use a group IV base stock oil, you can wear out the additives, but the base stock itself keeps on going.

DreamerGT

Wax hasent been a problem in oil since the 70's.

ShadyNinja

maybe not, but it is taking up space in the oil that a more useful additive could be using.