BOV question??

[BG5guy]

So, i have been doing research on the issue and have been finding the results 50-50. Half the seraches say a BOV on a Subaru is a bad idea because it tricks the ECU into thinking there is a leak in air and throws a CEL or runs rich. The other 50% say a BOV does not cause issues and is a good mod for any turbo'd Subaru. Anyone have any hard facts or seen any issues on other forums about this. Im debating if i want a BOV in my FXT. Thanks

[jospgut]

You should ask on the subaru forester forum...www.subaruforester.com.

[BG5guy]

thats where im getting the mixed feelings from lol. its either do it or dont do it lol. Also i just joined that site a few weeks ago and dont think people even know im around on there, which is why i asked here. I know alot of people on here have great knowledge in all that is subaru

[mycargoesvroom]

So, i have been doing research on the issue and have been finding the results 50-50. Half the seraches say a BOV on a Subaru is a bad idea because it tricks the ECU into thinking there is a leak in air and throws a CEL or runs rich. The other 50% say a BOV does not cause issues and is a good mod for any turbo'd Subaru. Anyone have any hard facts or seen any issues on other forums about this. Im debating if i want a BOV in my FXT. Thanks

Running a Vent to Air system will cause your car to run lean between shifts and under low throttle. I purchased a 50/50 for my WRX and on full or 50/50 the car would stumble between shifts and even died at a few traffic lights. If you feel like you NEED to get one run it in recirculation.

[BG5guy]

ya, thats kinda what i am leaning towards, a recirculation one is basically the exact same one i have, just looks cleaner inside the bay. I dont know why but i hate the stock look for the BOV, i guess im anal about looks under the hood lol.

[anothernord]

A) get a recirculated aftermarket BOV
B) install it
C) Enjoy your car running perfectly

Vent to atmosphere BOV's are stupid in my opinion, but they won't absolutely kill a car. I love my Turbo XS RFL in recirculated mode. There's a nice "CHHHHHHHSSSHH" between shifts, and it makes lots of noise as the turbo spools.

[Huffer]

Don't bother with it - spend the money elsewhere, like on a turboback and tune.

[BG5guy]

RFL's are good but draw way to much attention in my part of town. Couple crews out here that will box you in and be dumb once they hear a really loud pssshhhhhh from a car. I want something that is not crazy loud but i can hear , the stock BOV sounds like a smurf with gas. I have heard removing the snorkus in my car makes a huge difference, but not sure if its worth the hassle

[jospgut]

I have GFB Rec. BOV, and I love it, you can adjust the sound..

[phi11]

why is this in "Naturally Aspirated Engine"

[BG5guy]

oh crap, probably because im blind, my bad

[rougeben83]

silly goose, you don't have a turbo! :p



I've had the following BOV's on my car:

TurboXS RFL - simplest to setup, but the most prone to leak over time (the brass piston constantly moving in the aluminum case wears down over time), constantly needs to be adjusted and greased.

HKS SSQV - (ver. 1 w/ no adjustment screw), no adjustment needed, annoying sound, like a baby seal being clubbed on the head.

Forge - Never got working correctly, very hard to setup because it is done through changing out springs, it was either too tight and I would get compressor surge or too loose and it wouldn't hold under vaccum. The little adjustment screw did little.

All of these BOV's made the car worse on partial throttle. Like all VTA's they work when you're on full boost and needing to expel all that pressure out when the TB plate closes on shift, but the car will backfire and stutter and be more prone to vacuum leaks in all other situations.

I'm using a Greddy Type S on full recirculation now. I have not touched it in over a year, the car holds boost perfectly, and drives great in every other situation besides just hammering it.

That being said, the stock BPV is good to around 17-18psi or so consistently, any boost level higher than that and the valve tends to start cracking open because the spring is not strong enough to keep it closed against boost. Denting the top of it can usually allow it to hold around 20psi or so but its variable given the inconsistency of putting said dent into the top...

Go full recirc with an aftermarket valve. Believe me, I still get plenty of whoosing/chit-chit-chit/etc. to get my jollies going, and the sound does get old after a while, as most novelties do.

[BG5guy]

so ive been doing some research and have decided to get TurboSmart BOV. It is a direct replacment for the stock BOV and doesnt have super annoying sound. I like it better then the other styles because it is black which is the color of my car and im all about making things sorta match. Black silver and red will look sick when i pop my hood

[ouch1011]

I know you've already decided, but honestly unless the car is running way over stock boost or the stock BOV is broken, its a waste of money. If you don't have an intake, you won't hear a recirculated BOV regardless of brand. Most BOVs that are setup to make a lot of noise also fail in the most basic function of a bov--releasing the boost. And if you release to atmosphere, it will create so many drivability problems that you'll wish you'd never done it.

My thoughts...

[lord flashheart]

The reason your car dies at stop lights or has trouble idling between shifts is because when the engine is under vacuum (like between shifts) the vacuum opens the diaphragm and it stars sucking air thru the bpv and thats un metered air. You can test this by revving the engine, then letting off and sticking you finger on the bov outlet.

[ouch1011]

The reason your car dies at stop lights or has trouble idling between shifts is because when the engine is under vacuum (like between shifts) the vacuum opens the diaphragm and it stars sucking air thru the bpv and thats un metered air. You can test this by revving the engine, then letting off and sticking you finger on the bov outlet.

That only happens if the valve is adjusted wrong. Any valve capable of VTA should not be open with vacuum on the diaphragm and no boost in the boost tubes. If it is open, then the spring tension is wrong.

[lord flashheart]

Yep. That's what I was trying to getting at.

[BG5guy]

installed TurboXS recirc bov, so far works great. Not annoyingly loud and cosmeticaly is awesome. Thanks for the input tho everyone

[impreza_GC8]

So, i have been doing research on the issue and have been finding the results 50-50. Half the seraches say a BOV on a Subaru is a bad idea because it tricks the ECU into thinking there is a leak in air and throws a CEL or runs rich. The other 50% say a BOV does not cause issues and is a good mod for any turbo'd Subaru. Anyone have any hard facts or seen any issues on other forums about this. Im debating if i want a BOV in my FXT. Thanks

Running a Vent to Air system will cause your car to run lean between shifts and under low throttle. I purchased a 50/50 for my WRX and on full or 50/50 the car would stumble between shifts and even died at a few traffic lights. If you feel like you NEED to get one run it in recirculation.

You've got this wrong, it will be rich between shifts, not lean. The air has already been metered at the MAF but you dump it to atmos instead so there is extra fuel in there for the air that is now gone = rich.
Here's what I can tell you from personal experience, not from what I've read or heard. You can run any BOV you want, some are worse than others, but its possible that any atmos vent BOV will give you a bit of a stumble between hard shifts. My atmos BOV (HKS SSQV) does just fine, but I do notice it every so often, I like the sound though. I've also had fully recirced BOV's before, these are the best for the car, but will still give you the sound you're looking for. For the best of both worlds, there are 50/50 BOVs or adjustable ones that dump a certain amount to atmos and recirc the rest. Those are a great option but tend to be more pricey.

[SilentRacer]

^^ Exactly, it runs rich. I don't even see the point of 50/50 because you are still throwing off your air fuel ratio and therefore power, for sound. You can try to get your engine tuned to run on a different fuel map but once again why? Personally id like as much air going into the engine as possible because this is where the power comes from.

[impreza_GC8]

There is no real way to "tune around" a BOV. Its up in the air (no pun intended) as far as I'm concerned about how much power you gain or lose from a recirc/atmosBOV. When the throttle plate closes all the air that was between the IC and the throttle plate goes back in front of the IC with a recirc or goes away forever via BOV. If you are running a top mount then how much air are you really losing? I'm no engineer but theres not much there if you think about it, the IC isnt that big and it goes straight into the throttle body. Doubt you'll feel much difference. A front mount has more volume of piping and people say they can feel a pressure drop or more lag when switching to one, others say they feel no difference, plus theres the added benefit of a cooler charge from the IC being in front of the car so its possible the cooler charge negates any other negative factors like a BOV or added piping. But for the sake of argument, if you couple a BOV with a FMIC then theoretically you lose more air when shifting due to the increased volume plus it already takes longer for the air to come back through the IC due to the increased volume. But how much time are we talking? A millisecond? And how much extra air? 10 cubic inches? Anybody's guess. I think the certainly dont help, but also may not hurt, unless your car really isn't reacting well to the BOV at all in which case you shouldn't do it from the start. My car doesn't seem to mind it and it already runs pig rich anyway.
The 50/50 will lose less air to wasted atmos and put at least half of it back in. Will you see a HP difference from this? Probably not. Will you have a cleaner burn in the combustion chamber because the mixture is right for that split second, sure, but theres nothing burning in the chambers anyway with the throttle plate closed. That extra fuel just goes out the tailpipe and you might even get a nice fireball.
Anyway, there's my musings on the subject, enjoy.

[anothernord]

I personally think recirculated is just a better way to go overall. At partial throttle, the valve is open, and allows a little bit of air to get into the engine without the restriction of the turbo.

[BigWillieStyles]

Aftermarket BOVs vented to atmosphere are very common with Subaru turbo cars. I have a turbosmart one on my BH and it added a bit of fun to the car. I didnt notice any difference in power, no difference in fuel economy or anything else. Aftermarket items will hold higher levels of boost and wont leak as the factory items do with the simple stock spring design. I have also heard from other people that their car held boost for longer with an aftermarket item. The car will only run rich for a split second and you will probably get a little pop out the exhaust. I personally like it, but the car isnt my daily, and it would probably become a bit annoying if it was.

If I had to choose one again, and I might change, the HKS sqv one is a good choice as it has the signature high pitch squeal, but you can also change the insert to other sounds. Kind of like two bovs in one.

Many high performing competition cars used vented bov's.

You should be able to hear the factory item by just installing an aftermarket filter or removing the snorkle in the fender.