The Problem: Frequent belt failure on belt-driven superchargers.

The Solution: can be as simple as replacing a blow-off valve meant for a Turbo with one properly designed for a supercharged application.

I rarely see this discussed - but I often see this mistake. Pop-off valves for Turbo applications and Blow-Off valves for Superchargers are NOT the same thing, and not interchangeable.

Think of this: you are shifting at or near redline. The blower, at redline, is making maximum boost. Now you lift suddenly off the throttle (to shift, to brake for the corner, whatever) and you slam the throttle body shut. All that boost has no where to go, and runs backwards through the system looking for an escape. The blow-off valve is supposed to be that escape.

A valve for a turbo system will "flutter" - you can hear it if you listen - as it is designed to NOT loose all the back-pressure and keep the turbo spooled-up a little bit. This open-shut-open-shut action in a turbo-type valve pushes the belt-driven Powerdyne sprockets forward-and-back several times a second and the belt takes a beating. These same valves when applied to a gear-driven blower seem to work OK - but its just because the gears can take that kind of abuse where a belt cannot.

A blow-off for a Supercharger is designed differently and will open ONCE and dump the boost like it should on a supercharged system. It is much kinder on belts.

Over years of trial and error (and a LOT of money spent on blow-off valves), I still have not found a better blow-off valve than the one the Bosch engineers designed for boosted applications. Here it is, and at a darn good price too.

One more thing: Test your blow-off valve by making sure it holds vacuum and moves correctly from time-time. They don't last forever!