Originally Posted By: ZeeOSix
Originally Posted By: 440Magnum
Honestly Fram Ultra would top the list if it had the bypass valve mechanism like Purolator uses.
I don't have any qualms with Fram's bypass valve design. It's spring operated, and the valve is high temperature nylon material. Fram has tested the design 100%.
I'm fine with it also. But the Purolator bypass valve is, in my opinion, the most predictable of all the common types when mass production tolerances are considered. Its cheap to build, but its also very, repeatable depending more on the modulus of the metal its stamped from than on its physical dimensions which are subject to error in the production process. Its an example of very clever engineering to counteract problems in production... I admire that.