Quote:
Originally Posted by qqzj
Let's make a fair comparison, Pennzoil Platinum 0w-20 vs. Pennzoil Platinum 5w-20, is the 0w always better than 5w? I do not know. But judging from the appearance, there is nothing against 0w-20, but at least one thing that is against 5w-20. Any educated explanation will be helpful.
|
How is my comparison not fair? SubieNate is contending that 0w oils are necessarily superior
in every way than their 5w and 10w counterparts, which is an oversimplification, as I said. I picked Ultra for good reason, Pennzoil's flagship product didn't even come as a 0w oil until very recently. That product's claim to fame was deposit prevention. Coincidence?
I already mentioned some ways in which oils with higher W numbers are superior to their 0w counterparts. Go look up the specs. Pennzoil Platinum 0w20 has a NOACK of 10.8% while the 5w20 is 8.6%. All 5w20 oils must pass the TEOST 33C turbocharger deposit formation test which is part of ILSAC GF-5, 0w20 oils are not required to pass that test. SOPUS has stated that the type and quantity of viscosity modifiers in oil is a primary contributor to intake valve deposits, so the less, the better for DI cars. A quick look at UOAs will show that high quality synthetic 5w20 oils tend to be more shear stable than their 0w20 counterparts.
W numbers are all about performance in extreme cold, for those of us in cold climates that's important, but usually only for 1/3 of the year. Many here live South of the Mason-Dixon line and are looking for oil that can stand up to high temperatures. Optimal oil selection is about making compromises in the areas of performance which are least important, so for many users the W number is the first place to compromise.