Why does anyone throw away hp with a blow off valve?
 

I just don't understand why anyone would put a blow off valve on their STi, or WRX if it still has the stock turbo. I will admit the following things: it sounds cool, retards think that it makes your car fast, or faster, and that some girls just love them. I still don't understand it though becuase from what I understand you loose HP when you put one on. Just wanted to see what everyone has to say. My friend and I have been discussing this all week and I want some more opinions.

Nathan

I dunno, it's the ricer in me. I've been running one since 4 months after getting my car. I don't think many people would consider my car slow.

Right, but it does make your car slower than it could be right?

Possibly, but the nice pshaa sounds far outweigh the miniscule loss (if any) of power. Seriously I experience no lag after shifts whatsoever.

I have
 

an aftermarket BOV (APS), but only because I have a FMIC. Never "heard" it much with the stock turbo. PnP VF34 now (Stage 4) and I hear it on a regular basis. I agree that most that replace the BOV are looking for the "sound".

San

Why don't you explain to us all why putting the BOV makes your car loose hp...

I think it has something to do with the stock BOV being a recirculating valve instead of atmosphere valve. What it means is the air "let off" is circulated back into the manifold. Atmospheric BOV will cause the motor to run rich because the A/F meter does not measure the air traveled after the BOV.

I don't know if you will lose hp... I'm not sure, but you will be running a little rich. Might cause some problem at idle. But there are 50/50 (hybrid) BOV out in the market.

For higher boost applications, my understanding is that you will lose h.p. by using the STOCK BOV, as it won't hold over 19 psi?? That's the only case where I've heard of the BOV causing a loss of hp.

Along with luktang's comments on idle problems, you could also run rich in between shifts.

[QUOTE=keirnna]and that some girls just love them.[/QUOTE]

'Nuf said for me :D

[QUOTE=Imprezer]Why don't you explain to us all why putting the BOV makes your car loose hp...[/QUOTE]

Ditto.

There's a lot of misconceptions out there regarding BOVs. A properly adjusted BOV will not cause you to loose power. Many think that because a BOV vented to atmosphere will cause your car to run rich = less power. The rich condition is for just a moment between shifts.


edit: w/out turning this into a tech post; IMO there are potential problems w/ using an aftermarket BOV and the stock bypass valve works perfectly well at stock to mildly modified levels of power.

I read a good article over a year ago (think it was in SCC) that looked at several BOVs. Besides the aftermarket ones it also discussed stock BOVs including the WRX stock BOV. From what I remember it actually rated the WRX BOV well for most purposes. There are cases (such as San mentioned) where an aftermarket is the way to go, but unless you are doing major mods it really just comes down to personal preference and I don't think you can expect much of an improvement (or lose) with an aftermarket BOV.

Also take a look at what the big US Subaru tuners are including in their stage kits....

Chicks dig it.
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I'm gonna go with....

1. I'm retarded
2. Like King Rich says..."Chicks Dig It"

vrrrrrRRRRRMMMMMM... *PSSSHHH*
vrrrrRRMMMMMM... *PSSSSHHHHH*

"Ooh your car is so sexsy"

Hey it's a reason good enough for me. It's wierd though alot of the non-suby owners that I know ask me if 1) Did you put a CAI in? and 2) Did you put a BOV in?

although it isn't needed, i'd sport one as soon as i get an exhaust.

like everyone else said, chicks dig it.