2005 Subaru Impreza WRX STi showing HKS SSQV Blow-off valve

An under the hood look at the HKS SSQV BOV before it was recirculated on my 2005 Subaru Impreza WRX STi. Although the video may make it appear to be, this was not a cold start.

Category:

Autos & Vehicles

Tags:

• 2005 SSQV
• HKS STi
• 05 STi
• STi HKS SSQV
• STi blow off valve
• STi blow off
• Stage 2 STi
• Subaru blow off
• subaru
• STi
• impreza
• WRX
• 2005
• HKS
• blow off valve
• BOV

[ignit]

I never said a blow off valve can't help your turbo system... It can be beneficial to install a blow off valve if you are running high enough boost levels to cause "over spin" as you call it. My ej257 boxer engine and VF39 turbo do not exceed 17psi at peak boost with the ECU mapped for stage 2. This is not enough to cause my turbo to over spool thus making a blow off valve unnecessary. Most stock turbo systems will not run enough boost to cause over spooling or require a blow off valve.

[ignit]

@ignit If a BOV isn't necessary on your vehicle but you install one anyway, you might cause your air/fuel ratio to be unsatisfactory and more towards the rich side because your turbo will struggle to re-create the pressure that is lost when the valve opens up and releases the boost in the system. All I'm trying to say is... If you know when to use a blow off valve, they can help your car. If you don't know what you're doing... you will cause damage to your engine.

[m4airsofter]

@ignit I feel like that kind of depends. I agree, but it makes a difference if the bov is 100% atmospheric or 50% recirculating. If it's 50%...then I think it'd be fine on a stock sti. Not completely sure though. It's definitely unnecessary haha

[ignit]

@m4airsofter You're totally right. I should have specified. Most guys that throw a BOV on just for shits are going to run it 100% atmospheric so they get the loud chirp during blow off. If a person feels compelled to install a blow off valve in an unnecessary situation then it would be a good idea to go with a valve like the COBB XLE BPV which can easily be changed from 100% atmospheric, 50% atmospheric + 50% recirculating, or 100% recirculating.

[m4airsofter]

@ignit yup completely true, a lot of people just want the sound and don't know the consequences. But personally, if I was gonna get one, I'd want one that has the flutter instead of a chirp. Gotta love that sound haha

[ignit]

@m4airsofter Everybody loves a good flutter sound but just be sure it's not compressor surge :P. It makes me cringe when I hear a ricer's compressor surge through the BOV and he has no idea that it's bad for his turbo lol.

[Sevensix9]

@ignit "over spool"??? Maybe your choice of words is wrong, but the reason for a BOV or BPV is when the turbo is making positive boost and you let off the throttle, the throttle body closes and the positive boost has to go somewhere, air, just like water will travel in the path of least resistance. In this case it will push back into the turbo causing the wheel to suddenly stop and backspin, damaging the shaft. If you want knowledge pick up Maximum Boost, on Amazon, that book is PSI God

[Hondas337]

over spooling a turbo? O.O i wish i had that problem.... the reason a BOV is bad on a MAF car like, most euro cars, is because once the air flows through the MAF sensor, it tells the pcm exactly how much air is entering, when the valve BLOWS OFF AIR, it causes the cars a/f ratio to run rich, if you want a BOV, do a Map only tune.

[m4airsofter]

@ignit it makes me cringe every time I hear a ricer in general hahah

[Ru55ianGrim]

Dosnt a blow off valve HELP the turbo not over spin?