I mean a bypass valve for the boost when the throttle is closed(especially after a WOT blast)Basically a bypass valve would open letting the air recirculate back around to the inlet side of the turbo and prevent the boost from stacking in the up pipe and reversing direction going back into the turbo.I have a bypass system on my Mustang but I dont know if it would work on a GN due to the different ECM.The guy at KDK said the reversion puts a big strain on the turbo because the air pressure shoots way up when the car is under boost and the throttle is closed.
He's talking about a Blow Off Valve (BOV). Hardly anyone in the Turbo Regal circle uses them. They're more comon on the turbo, manual tranny, imports.
However, I don't really think it's a bad idea to use one (on our cars) as it *should* help prolong the life of the turbo (especially if you're in & out of WOT a lot). HOWEVER, be aware that it may take some patience to set up and keep from bleeding off at high boost levels.
I've got a Talon BOV in the shop that I haven't done anything with. Maybe one day I'll fool around with it and see what happens. Other than that, I'm just going by what I've seen/read/heard. What do some of the others have to say?
I have a BOV and it doesn't give me any trouble. I always hated the way my turbo shuttered when I let of the throttle while in boost. I must admit that doesn't happen all the time but now when it does happen I know I'm not slamming my turbo. It was a pain in the ass once...It would release boost while I was still in it...it turned out to be a weak coilpack. It wasn't missing bad enough for me to notice it but appearently the BOV is very sensitive and when the weaker pack fired it didn't generate enough exhaust to keep the turbo spooling at the rate the other cylinders did. The BOV sensed the drop off and released all boost. I was pissed because I couldn't figure it out. I changed the coilpack and ign. mod and wholla no more problems. So if you do decide to use one remember this because it gave me fits figuring it out.
I wasnt planning to use a BOV.I wanted to install a bypass system.A bypass stays closed from 0" of vacuum(wot throttle) to whatever boost it sees.It doesnt open until the engine makes at least 12" of vacuum(throttle closed) allowing the air to recirculate back to the inlet of the turbo. The result should be a smoother transition back down from wot to idle by not creating a vacuum at the TB and starving the engine of air powersix