My question is; What are people gaining from upgrading the Bypass valve. According to NST's Website, they can get 9.5psi and 231whp with the stock bypass valve. Under what conditions will something like the Forge007 help.

More boost?
More hp/tq?
More consistant boost?
Earlier boost?

If it holds the boost even at 9.5psi than what could you possibly gain by upgrading. I've seen posts of people saying the gains of a new valve are great,..yadda yadda but I can't find any dyno's, numbers, or even explinations of what is being gained.

BTW what is the whoosh sound I hear when I slam on the gas right after an upshift, Excess boost? (note: not when I let off the gas)

 

they change the bpv because they hold boost better or something.

some supercharged tc's are complaining that when they hooked up a boost gauge, they were only getting 6 psi, which could be because the bpv is letting psi down.

 

Yea definetly upgrade teh BPV. It lets you get into boost earlier and it holds it all the way up to redline. If you get the 9.5 pulley you WILL NOT hit anywhere over 7psi. I do have a turbo XS im selling though for 70 dollars with shipping. Pm me if your interested!

 

The stock BPV is designed to bleed boost under partial throttle conditions intentionally to prevent heat build up and for smooth casual driving. Decreasing the lockout threshold on the BPV means boost will be able to build under partial throttle conditions giving you "more response" right. ...BUT that won't increase WOT boost or performance. So essentially (other than the fact that people claim it won't hold the 7-9.5psi) , an upgraded BPV will give you the sensation of a more responsive throttle because you won't have to put your foot down as far to get boost to build?

+ More responsive throttle fun factor
+ Possible ellimination of "lost" top end boost - debatable
+ Easily swapped out

-possible effect on gas milage
-possible increase in heat build up
-no WOT advatages (assuming no stock leakage)

Sound about right?

 

No its the stock BPV has a diaphram in it that contracts, underfull boost that diaphram is supposed to push itself shut, the problem with it is that its made of rubber I believe and when enough pressure gets behind it, it will push the diaphram open and release the built boost.

 

yeah im in need of a better bpv!