Just a quick question, do blow off valves actually serve a purpose. I know that they sound great, but do they increase performance? Also, do they tend to mess with the engine/engine lights at all? Ultimately, I am wondering if they are a positive addition to a suby wrx. If so, which one do you all recommend? Thanks!

 

don't need one until you upgrade your turbo. The stock one will basically hold as much boost as you can get out of the stock turbo.

All it does is make your car run rich and cause you to lose boost in most cases, yeah it makes your car sound cool, but it's gets old after a while.

Also, the search feature is your friend...use it. (=

 

Yea, not all BOVs make noise like the ones most people use, its mostly for sound.

 

So basically what your saying is if I buy a very good B.O.V and install it, I will be loosing boost from my turbo? Or does it only make the sound.... Please reply, i'm looking forward to buying one but im confused now. Some people told me they give more boost and better sound now i read here it makes your car slower.... umm.

 

correct. for further clarification

BOV=blow off valve - 100% atmospheric
BPV=bypass valve - recirculates air back into the intake

the cars come stock with BPV's and even when upgrading, theres no reason, other than sound, to get a 100% atmospheric BOV

 

Would I be losing any power? The only reason I want one is for the sound, I found a B.O.V for sale, it allows you to choose between loud and soft "Pshhh" noise.

 

if you lose boost you'll lose power. a cheap BOV will leak badly. One of my buddies got a BOV with an ebay TMIC and it was a lot weaker than the stock one. You could push the cylinder in very easily on it, the stock one you can barely push the cylinder in

 

Hmmm, then i guess i wont be needing one in that case. I have alot of SPT parts on my 05 Legacy GT, CatBack full exhaust with up/down pipes and header. SPT intake. and a few other STi parts such as oil caps and pedals. MBasile, so would it be bad if i got one then, cuz its not a cheap one. 270+ US Dollars.

 

aftermarket BOV: $270, bad for your engine
stock BPV: free, good for engine

 

Alright then thanks. Im a newbie to Subaru Tuning so i would take your word for it. But are then any after market BPV's?

 

Yeah, there are aftermarket BPV's (also called recirculating BOV's) but the only point to buying them is if you're boosting more pressure than the stock BPV can handle. You cant really hear them any better I don't think.

 

And with an Atermarket BPV i'd gain a little more boost from my turbo without hurting the engine?

 

no, you'd have the same boost. cheap BOV's leak the boost your turbo is creating, thats how you lose boost and power with them

 

Alright then thanks for the help. Like they say "You learn something new everyday" I thought i was goin' to go to bed stupid today. Hehe thanks.

 

no problem, when I first got the car, I wanted to get a flowmaster exhaust and a CAI :rotfl: oh how we learn