Does the bypass allow full flow or partial ?

 

full flow. Most bypass valves have an open skirt area equal to the total area of the intake ports of the filter. Discounting frictional differences, it's full flow. There was an SAE paper I had on high performance filtering and the operational effects the filter media placed on oil pressure controlled systems like variable timing systems, but it was a download and not a mailed paper, so it's no longer available to me without paying for it again. The findings were kinda cool if you're really excited about the intricate operation and effects of seemingly mundane things.

Will

 

i've noticed a lot of burn off with mobil 1 and especially royal purple. i've switched to amsoil and hope i dont have to switch again. car is driven aggressively and gets a change between 2000 and 3000 miles.