Whats a bypass valve?
 

Is a bypass valve the same as a blow off valve?

Sort of.

Blow off valves are found on cars with superchargers. Bypass valves are on cars with turbos. They both serve the same purpose, but a Bypass valve can throttle, where a blow-off valve is either fully open or fully closed.

On a Turbo, the bypass valve can be programmed to allow a pre-determined amount of boost. This means that you can actually change the amount of boost by doing nothing more then changing the program.

I have seen where bypass valves have been adopted for Superchargers which is really cool as they allow you to change boost w/o changing the pulley.

ohhh wow ok so thats why boost controler is for right? It controls the bypass valve for turbos? I allways wundered how you are suppose to control the boost from a turbo. Ok well I have a vortech... not on yet but I was told to ditch the bosch bypass valve for somthing better... so I'll prolly go with a blow off valve either way. Any recomendations? I found some on ebay for like ahhh $80 shipped, but I have a feeling somones gonna tell me they are sh!t. Wanna make sure first though.

...i thought it was the other way around.....blow off valves being more used for turbo applications...just fully open or closed to release pressure in the intake housing before the throttle plate....

no clue though, could be wrong....not much of a forced induction kinda guy.

yeah i think its the other way around

and i thought it was kinda like a waste gate on a turbo or in the case of the vortech s/c

+1 im not to well read on power adders but thats the way i thought it worked also

Fawk....I switched these around. My bad. Not the names goofed, but the concept right.

Whatever you do, you should stick with a standard valve arrangement for your supercharger. I only know of one supercharger where a wastegate was used to program the boost.

To make this work, you get a smaller pulley for more boost, but then limit the boost with the waste gate. This allows the boost to come on sooner which is awesome. Rather then the boost increasing with rpms, it stays the same. I really like the concept of doing this, but I am not sure you will find a tuner comfortable with the arrangement.

that would be the vortech system featured in MMFF

actually it was custom and probably not worth the cost either. hey, it was a cool idea though. ingenuity is what i call it.

bypass valves only lets pressure off when there is a vacuum on your engine.

blow off valve has a spring that bleeds air off at certain boost levels.