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

[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.

[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.

[m4airsofter]

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

[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

[Ru55ianGrim]

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

[roman21000]

I thought that if u add a bov like this one to a Subaru it hurts the engine, because it was meant to have the air resirculated...?

[ignit]

@roman21000 Yes it can, which is why if you read the description, it says "before it was recirculated". I filmed this simply to show the sound and I only un-recirculate the BOV when filming the car. Otherwise, it's always a good idea to run a BOV recirculated on a subaru.

[aliennationyo]

i have the same blow off valve but black and silver. how do u add more boost?

[ignit]

@aliennationyo Your blow off valve actually has got nothing to do with increasing boost. In fact, it's job is to do the exact opposite; it quickly relieves the turbo of the pressure that builds up. Common misconception is that you can just up the boost and your engine will put out more power but this is a very risky operation and will most likely lead to other issues. Boost controllers allow you to change boost levels but please leave this to a professional tuner to ensure safe tuning.

[ic0627]

Do you need to refresh the ecu? I wanna install one :) what else need to be done when u install a BOV?

[DeathI0k]

This sound is so beatiful <3 Here, where I live there is few subarus and always when I hear that blow-off valve sound, I know it is a subaru

[ignit]

@DeathI0k I wouldn't drive anything but a subaru after having owned my STi :)

[coltsuperocean10]

....without sounding naive, does a BOV increase performance? 

[ignit]

@coltsuperocean10 Depends on the car and the scenario but otherwise from my experience... Not one bit. In fact they can cause the exact opposite, a loss of power. Most install them just for the sound they make.

[illestDUBSTEP]

I was curious if running one of these BOV's would damage my car in anyway. I own a stock 2003 WRX. Kind of just want it for the sound to be honest. Thanks.

[ignit]

@illestDUBSTEP As I've stated in previous comment replies, replacing your stock bypass valve with a blow off valve that does not recirculate (ie. the HKS SSQV) will cause your engine to run rich. A very common side effect of this will be an increase in turbo lag which might seem like a loss of throttle response as your stock turbo system may struggle to make up for the lost air that is blown off by the BOV. You can refer to my reply to rmx92 as I state one way of correcting this issue.

[illestDUBSTEP]

@ignit Thank you for the honest response.

[Prototypexl]

@ignit A simple and cheap 20 dollar manual boost controller will also fix his issue, lol.

[ignit]

@Prototypexl True, a cheap manual boost controller such as Hallman's MBC can help but recommending somebody install one on their car that does not have a full understanding of and may have never used a MBC before is disaster waiting to happen. If somebody can't live without their HKS chirp then I'd much rather see them spend the money to install an electronic boost controller (ie. Grimmspeed's EBC) to replace the stock solenoid and get a pro tune. Your car will love you for this :)

[Prototypexl]

@ignit Good point. If he doesn't have the basic knowledge about BOVs than he shouldn't be tampering with an MBC on his own time as a test.

[Lonehawk2k4]

can some1 tell what thats for im an uber noob but id like to start learning the mechanics of a car so i thought id ask around youtube

[ignit]

@Lonehawk2k4 Essentially, a blow off valve is used to relieve the turbo of the pressure that's built up. They're seen more commonly on cars that run a higher than average amount of boost as this is when they truly serve a purpose. Some install BOVs simply to achieve the arguably desirable noise of the blow off. When used improperly they can cause your engine to run very rich which can potentially lead to other problems down the road. Hope that helps :)

[acidmatar]

@ignit at what psi for the turbo would a bov like this work best and most properly ?

[ignit]

@acidmatar Well many will argue with me and there is really no simple answer to this question. There are many factors when tuning a vehicle. This BOV will operate just fine at any psi, it just might have negative effects on your air/fuel ratio, etc.

[acidmatar]

@ignit oh ok , thx for the reply , i dont wanna make any future mistakes when tuning , trying to gather as much info as possible to get a car thats fun and not expensive to fix if trouble arises

[ignit]

@acidmatar Well I can only speak from experience when I say that if you are looking into an STi, they are EXTREMELY fun to drive but not so fun to fix and even less fun to pay a mechanic to fix for you.  This type of car demands that you keep it well maintained if you plan on keeping it for any length of time (ie. Oil, filters, engine refreshments, etc.)

[nags555]

@Lonehawk2k4 @ignit basically that translated into noob speak is it stops the turbos or supercharger from blowing up in high performance situations, but some people install them just for the sound :)

[rmx92]

Hey I just picked up the cobb TBE and cobb short ram intake for my 05 sti. I have been looking for a BOV but some people say it runs really rich on a stage 2 unless you buy a 3 bar MAP senor? This true or do you not have one and your still running fine and not to rich?

[ignit]

@rmx92 Those people are exactly correct. I run the same intake, exhaust, and tune with the HKS SSQV and it does run very rich. I correct this by hooking the SSQV up to recirculate the air back to the 1" return hose. You lose the loud sound of the BOV but your engine will run a lot better.

[ignit]

@rmx92 If you haven't already picked up a BOV, might I suggest the Cobb BOV/BPV. It's comparable in price to many other name brand BOVs like the SSQV but it's conveniently adjustable so that you can have the valve: 1. release all the air 2. recirculate half the air and release half or 3. recirculate all of the air back into your turbo system. I've seen some great reviews on this valve and am in the middle of rebuilding my '05 STi and once I'm done, I'll be trying out the Cobb BOV.

[jr8688]

NICE



[IronMaiden347]

Can you put this on a stock sti and get the same type sound or do you have to have a lot of modifications?

[ignit]

@IronMaiden347 It should sound very similar on a stock STi.

[IronMaiden347]

@ignit Thanks man

[Oddish08]

is that the stock bpv adapter??

[ignit]

@Oddish08 Yes.

[escargot28]

Nice

[kittychan206]

I think I just wet my pants!

[TJH1991]

do you have to do any tuning on an sti after buying a blowoff valve? i also have cat back exhaust and cold air intake installed

[ignit]

@TJH1991 Very highly recommended. The Cobb AcessPort V2 is an extremely useful tool for creating logs and ensuring optimal engine performance. My STi was in a Stage 2 tune during the video and it was running very well with the HKS BOV. Hope that helps.

[iNNoCeNttDReAMs]

I want to get one just for giggles

[EpicMotion]

Love the fucking sound of it!!!

[VangTou93]

SICK im thinking about getting a bov

[MichaelAdrianeTorres]

That is sick dude

[stuwk1]

fuckin nice