[empower-auto]

Originally Posted by Scott@HKSUSA

All grades are "made up." SAE viscosity ratings are just that - a standardized viscosity rating system. If you started your own oil brand, you could specify a SAE 7W-36 blend if you wanted to. Now because HKS oil is designed & offered for modified or all-out racing engines, it isn't API certified, but that has nothing to do with the SAE viscosity rating.

Why does HKS offer such oddball viscosities? Their goal isn't to be a factory fill so they don't have to worry about the factory recommendation for general/daily driving in any/all conditions. Their goal is to blend the optimum viscosity for maximum power with maximum protection in a modified or all-out race engine in racing conditions. Mitsu. recommends 5W-30 for my Evo, but HKS' 4B11-specific oil is 3.5W-37, so it's a little lighter when it's cold and a little more stable when it's hot.

And I'll let you guys in on a little industry secret - despite the dozens of companies that offer performance oils, there are less than a handfull of refineries that produce, blend, and bottle for all of them. That isn't s slight towards anyone or any particular brand, that's just how the oil industry works in our little segment of their market. Specify a viscosity, specify a base, specify an additive pack, supply your packaging and you too could be off & running with your own brand of SAE 4.8W-26 oil.

HKS has a ton of manufacturing prowess, more than most, but even they don't have their own oil refinery. Not too many do.

And this is why my car is a rolling ad for HKS parts right now