BOVs: recirculating v/s atmospheric venting

Sketchy564

Sketchy564

Driver
So im throwing my other SR back in the car pretty soon, and im replacing my turbo with either a rebuilt t25 or an s15 gt28r. To protect my investment, i want a legit bov. I have a fake greddy RS currently, and it surges a lot. Basically doesnt do shit, also leaks a little bit.

im thinking of just getting a legit greddy since its easy to switch with the same flange, but id prefer something different, so im also looking into hks ssqv's, and possibly the tial since they sound nasty and i havnt heard anything bad about them

i noticed a lot of people run BOVs that vent into the atmosphere, with SR20s or just in general. The HKS ssqv's all seem to be atmospheric venting, same with everyone ive seen with the greddy bov's, even though they have the option to re-circ, and even the tial in the video in my WTB thread, as well as all the other ones on youtube seem to be atmospheric



my question is, isnt it a lot better to recirculate the BOV? From what i understand if you dump it into the atmosphere, you screw with your MAF reading, and you also have a bit more lag in between shifts. Not to mention every time we pop our cars out of gear after hitting boost, they want to die out

does it actually make a big enough of a difference to matter? Would it be worthwhile to invest in a recirculating BOV and making it work? From what ive read, you can fix the dying out issue if you have something to tune your car with, like an SAFC, but what about the MAF reading and the lag?

also are there any benefits to running your BOV vented as opposed to recirculating? the only thing i can think of would be a louder sound, which is cool and all, but with my new setup im more concerned about squeezing the most power, having it run well, and longevity of the turbo and motor life


Just looking for opinions and input from experienced people on here who actually know what they are talking about

thanks in advance
 
synapse ftw. i wouldnt do the HKS bov, theyve given a few of my friends a bad experience
 
ive had my HKS SSQV for about a year now still no complains about it. its currently blowing off atmospherically. and only issues ive had aret the wanted to die when in neutral after boost, as well as it running rich every time u blow off. Im in the process of buying the recirculation adapter and running a hose back into the intake after the MAF. only problem is im debating on switching the bov over to the hot pipe as i currently have it on the cold side, and would have to run a pretty long hose.

cliff* never had a problem with HKS SSQV will vent it to recirculation soon.
 
Emeru said:
ive had my HKS SSQV for about a year now still no complains about it. its currently blowing off atmospherically. and only issues ive had aret the wanted to die when in neutral after boost, as well as it running rich every time u blow off. Im in the process of buying the recirculation adapter and running a hose back into the intake after the MAF. only problem is im debating on switching the bov over to the hot pipe as i currently have it on the cold side, and would have to run a pretty long hose.

cliff* never had a problem with HKS SSQV will vent it to recirculation soon.
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i have mine on the cold side as well, ive heard mixed things about which is better

hot side is closer to turbo, cold side is closer to cold throttle body, yadayadayaa

it seems like having it on the hot side would make it worlds and worlds easyer to recirculate to the intake since its on the same side of the engine bay
 
+1 on the HKS ssqv. i've had mine for a year and some months before i crashed and during that time frame, i haven't had any problems with it and no lagging between shifts that i can note on. it was atmospheric as well as hot side mounted
 
HKS SQV is great for recirc. I'm running a Blitz right now, but I'm making the flange for the HKS and I'll be running that and recirculating it.
 
if your car wants to die after you get off boost you prob have a leak or your bov is set to soft so your maff has to catch its self when the bov goes to close but still leaks in air the maff does not read. had this happen a few times

i usually let the car idle and put my hand up to the bov to see if it has any suction to it, if it does your gona need to tighten the spring a bit to close off any air getting in after the maff. should also fix erratic idle if its set super soft.

sometimes it'll still be to soft and you'll have to tighten it a bit more but then you'll go in surge territory

if im incorrect let me know vetts:D
 
metalrocks12 said:
if your car wants to die after you get off boost you prob have a leak or your bov is set to soft so your maff has to catch its self when the bov goes to close but still leaks in air the maff does not read. had this happen a few times

i usually let the car idle and put my hand up to the bov to see if it has any suction to it, if it does your gona need to tighten the spring a bit to close off any air getting in after the maff. should also fix erratic idle if its set super soft.

sometimes it'll still be to soft and you'll have to tighten it a bit more but then you'll go in surge territory

if im incorrect let me know vetts:D
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Well the thing is, my turbo has always surged, and id never really hear the BOV go off. I softened it up till i would hear it a little bit, and i still barley hear it, and it stilll surges a lot, but on idle it has suction like you are describing. Before i softened it, it never had the dying out issue, so this is definatley related to the BOV

so it seems too tight since it surges, but at the same time it seems too loose since it sucks in on idle. This is what made me realize, its a shitty blow off valve and its never going to function properly
 
yea i remmember, its a cxracing greddy knock off but i have had no problems with them. im rocking one now on my z and its great
 
well i tried roberto's cx racing BOV which i heard work in his Z in person, and on my car it still surges and doesnt make the distinct noise that a type-s knock off should. We adjusted the spring tight enough so it didnt suck in air on idle, but not too tight

would there be any other reasons why a BOV wouldnt work and it would just surge?

it is on the cold side of the intercooler piping, which to me would seem better since as soon as the throttle body shuts, the air lets out right there. He suggested trying it on the hot side and seeing what happens

I will probably do that, with an hks SSQV, and just completley tighten the "greddy" for now untill i can block it off, but i just want to make sure theres nothing else as dumb as a crack in the coupler, or an issue with the turbo itself that would cause it to surge


i havnt been able to pull the inlet off and check the turbo itself after running the car, but when i first put the turbo on, it had basically no shaft play in any direction whatsoever, and it has been surging and not blowing off since day 1
 
Sketchy564 said:
well i tried roberto's cx racing BOV which i heard work in his Z in person, and on my car it still surges and doesnt make the distinct noise that a type-s knock off should. We adjusted the spring tight enough so it didnt suck in air on idle, but not too tight

would there be any other reasons why a BOV wouldnt work and it would just surge?

it is on the cold side of the intercooler piping, which to me would seem better since as soon as the throttle body shuts, the air lets out right there. He suggested trying it on the hot side and seeing what happens

I will probably do that, with an hks SSQV, and just completley tighten the "greddy" for now untill i can block it off, but i just want to make sure theres nothing else as dumb as a crack in the coupler, or an issue with the turbo itself that would cause it to surge


i havnt been able to pull the inlet off and check the turbo itself after running the car, but when i first put the turbo on, it had basically no shaft play in any direction whatsoever, and it has been surging and not blowing off since day 1
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Turbo surge on that small ass turbo isnt gonna do diddly squat... Either way make sure your Vac line is coming from the correct source and is large enough to provide the signal to the bov

Stay away from cheapo knock offs and get a quality working BOV - like the Tial - install on hotside and forget it

Did you ever figure out why your boost gauge is not reading Vacuum? That could be why no bov is working
 
PB&J said:
please stop making threads!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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no one gives a fuck if you dont like reading my threads. if you dont want to read em, dont read em. I made the thread so i can figure out an issue with my car, not yours.


BiG MiKE said:
Turbo surge on that small ass turbo isnt gonna do diddly squat... Either way make sure your Vac line is coming from the correct source and is large enough to provide the signal to the bov
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the vaccum thats connected to the blow off valve is coming from the top middle little nozzle above the throttle body. Its not clamped on the BOV, but it seems tight enough. doesnt leak air when im in the engine bay revving it, and it doesnt come off unless you actually try to get it off

Stay away from cheapo knock offs and get a quality working BOV - like the Tial - install on hotside and forget it
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Yeah unless i get it to work im buying an HKS ssqv and a new hot pipe i found with the flange. But still, this BOV worked fine on roberto's ZX, so i dont see why it wouldnt work directly next to the throttle body on my car.

just curious, why do you say "install it on the hot side and forget it"? Would having it on the cold side have anything to do with it not working properly?

Did you ever figure out why your boost gauge is not reading Vacuum? That could be why no bov is working
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Well the boost gauge is connected to the little nipple on the bottom of the throttle body in the middle. Theres a vacuum line that comes from the TB nipple thing, and theres a smaller white vacuum hose thing that comes from the boost gauge. Where they meet each other, the smaller one from the gauge goes inside the vacuum line from the TB and its zip tied around tight. Doesnt feel like it leaks at all. It reads PSI fine, but only inHG when im lightly on the gas, not when its idling.


Also, if it matters, the vacuum line that comes from my waste gate is connected to my ghetto ebay boost controller, and then from there to a little nipple that i screwed into the hot pipe. Its on there good with teflon tape, and doesnt leak at all
 
Silly kids and their bovs and turbos.


I ran a greddy type s with my 2871. I picked it up the other day and tried to push it open. I ran it so tight it didn't open.

Suck it/deal with it/not my chair, not my problem.
 
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