Blow-Off Valves

Is there really that big of a difference in performance between the Apex'i Dual Chamber, HKS SSQV, Blitz something or other and all those other ones, I mean how different can they be, right?

only if you are pushing MASSIVE boost does it matter

I'd say that it doesn't really matter until you're boosting more than 15psi. I have a Blitz DD and I absolutely love it.

Well when it starts to matter, which one is the best? Or at least which one(s) to stay away from?

When you start pusing more boost, you want something with a pretty stiff spring. Like the greddy series:

type s-for average apps up to about 20psi
type r-for heavily modified
type rs-supposedly a good mix(better color too)

Sequentials are supposed to be more responsive IIRC.

TurboXs and Blitz are probably the loudest

Greddys are all around.

Some are designed around recirculating so they are gonna be quieter.

Valve diameter comes into play when you're FLOWING a lot of air. A lot of boost doesn't mean you need a bigger BOV unless you have a big turbo.

All the name brand aftermarket BOVs are good. Stay away from cheapies and don't rig a 500whp setup with a bosch $25 replacement.

ive heard the turboX is crazy loud like to the point that it gets very annoying

Valve diameter comes into play when you're FLOWING a lot of air. A lot of boost doesn't mean you need a bigger BOV unless you have a big turbo.


Werd.


Big Flow - TiAL > *

i have a hks ssqv on my probe its loud and it get annoying at times, its like a damm bird cherping all the time, at hi boost(12psi) is like a hi- pitched screem, its fun but loud, the hks is really responsive, i had to back out the bot in the back to make it less responsive and stay open longer b/c it would open and shut way to quickly to let all the boost out, over all i like the hks ssqv, if you ar wondering about sound i have a good web site

http://www.935motorsports.com/bovmedias.htm

its full of soundclips, of the various bov,

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yeah those are good clips and vids, i have seen that page before..My favorite was the third clip with the supra, sounds pretty nice!

I believe the ultimate factor in sound is how much your pushing and how hard its being pushed. Air that is.

Something with a stock setup and a nice BOV isn't gonna sound as good as a heavily modified engine with a like a T66 pushin 20psi. Thats where you don't even get a whistle, its just a whoosh of air. Sounds like an air comressor or air brakes on a truck. Thats the best sound.

Thats not what my Type S sounds like.:( Damn open wastegate and recirculation.

Noise is what really makes the difference.

Mate of mine had a Blitz somethingorother on his WRX and it wasn't flowing enough causing compressor surge..and he's only running 18psi or something.

A LOT of the Nissan guys just run the stock BOVs, i've seen a heavily worked circuit Skyline still running the stock ones...

what do you mean ONLY RUNNING 18PSI??? that is freakin super alot...you make us sound like we are pro dragers around here who see people running that all the time LOL.

lol super alot lol

my type S sounded just like that when its vented off the atmosphere. however since i routed back to my intake, it sounds alot quieter. i loved the way it sounded when it was just vented, but the car drove like shit.

A LOT of the Nissan guys just run the stock BOVs, i've seen a heavily worked circuit Skyline still running the stock ones...

Look at WRC cars... they only have a little stamped steel one like OEM.

it also make a difference if you have hard pipes or th shitty palstic piping, the hards pipes will give you a better sounding hi pitched noised then plastic, also about whistling thing, i find on the hks ssqv with 3-4psi or less when you let off its the sound of the air-breaks form trucks, but anything after 4psi is a whistle, that is my finding with the ssqv, as for the greddy typ-s that is one mean sound bov vented or re-circulated, tat doesnt noe it but one day we were driving together on the hi way and i guess he was boosting a little and let off in a tunnel omfg.. that shit scared me, at the time i didnt have my hks.. man it would of sounded sweet for both of of to blow off at the same time in a tunnel, man blow off in a tunnel is great (no pun intended :-) )

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haha you think my type S was loud? try benny's RFL in a tunnel, it scares the shit out of everybody man, its freaking great!!! :bigthumb:

what do you mean ONLY RUNNING 18PSI??? that is freakin super alot...you make us sound like we are pro dragers around here who see people running that all the time LOL.

Well, that's not that high for a WRX. If I recall correctly, the WRX stock boost is at 14? So 18 wouldn't be so much, that's like me (SR20) boosting to 10psi, and thats pretty safe.

it really depends on what turbo its running, but i don't think the WRX boost 14 psi stock, i think its more like 10-12 psi. a STi boost 16 then tapers off to 14 stock.

18 psi on a T4 is freaking alot, thats around 400hp.

How bad was the open atmosphere tat? When my rec. hose came off, the car backfired like hell and shut off. Talk about scary.

BTW, Tat, what's a "larger mounter intercooler"?

HKS i like it, if recirculated with the yelow flange, sounds good!
BUT if its all atmospher, the car stalls on idale sometimes...??? don't knw... i need to pay $200 to retune the fcon thing i was told to get rid of the MAF...

BTW, Tat, what's a "larger mounter intercooler"?

my mistake as a typo, your the first person to actually notice, lolz too bad i'm too lazy to change it.

anyways to answer nissanfantic's question, mine would stall out, however i use the SAFC and used the anti stall function. the car would have seriously shitty gas mileage, and it would back fire every time i let off, however it would not stall, but i can't drive down a busy street becsaue i would fear that a cop would pull me over.

from driving down a normal nyc street, i would backfire atleast 3 times. it gets very very annoying. i usually let the thing vent off for a day just to hear the noise, then i get annoyed after like 20 miles of driving, then i would recirculate it again. then after a year or so, i vent it off again. lolz it doesnt' cost me anything, thats why its soo good to buy a BOV that gives you the option to do one or the other. thats why the greddy type S gets my vote.

So, you're saying you can have a vented even with an S-AFCII?? I thought someone said something about the S-AFCII fixing the problem and you didn't have to recirculate...

the SAFC prevents it from stalling, but it doesnt' prevent it from backfiring.

So the only way to not to have a vented bov and not have the engine run like shit is to have a full stand alone?

every car is different. some guys i know can run a BOV VTA no problem. while people like me will have problems. however yes the only true way to run it is to elimate the MAF and switch it over to a MAP sensor from a standalone.

WRX stock boost is at 12. Found that out from my WRX friend. That means 18 is not considerably high then.

different motors have different boost, WRX is 1.5 k pascal, SR (mine) 1Kpscl.

i have more hp then the WRX ...

wtf are you talking about 18 is high. That means higher octane gas, larger injectors, big nice intercooler, there is no way you could RELIABLY run 18psi without setting up a bunch of stuff. Most people will start out with a set PSI and bump up 1psi at a time, and that is 6 overstock....

I know it's high, but not in those terms. 18psi for a mostly stock SR20 is damn high. 18psi on a WRX motor with a few bolt-on's isn't so dangerous. 18psi for a WRX is like 14psi on an SR20, not too dangerous, with a fmic and some bolt-ons.

I wish I could run 18psi daily =p

PSI is not a good way to rate power. You can make the same power at 18 psi from a T3 as you can 9 or 10 psi from a T66. PSI isn't important. Flow is important. If this wasn't true, you would never need to upgrade turbochargers.

every car is different. some guys i know can run a BOV VTA no problem. while people like me will have problems. however yes the only true way to run it is to elimate the MAF and switch it over to a MAP sensor from a standalone.

Where would you find a MAP sensor. Cuz mine backfires alot and it stalls alot also...like alot! And how much would they cost?

OR would it just be better to get the SFAC or whatever and stop the stalling?

Thanks

i could be wrong but i think a stock 227 hp wrx runs 16 psi stock doesnt it? my buddy has his up to 17.5 with only minor tweaks + CAI + cat-back
so yeah 18 is no biggie in a wrx
not sure about what psi an STi runs though

MAP sensors require a different engine management system. Its not a bolt on affair.

16PSI and 225??? lol yeah right.

its 14 psi then but not less than that

when i went to the autshow yesterday, the 2005 impreza has this freakin small @$$ turbo in it. When i went and looked at it, i was thinking it would be cooler on a small go cart. Then i went over and got into the STI, it had bigger turbo, but still kinda small for what i think that car can handle. Nonetheless, those IHI turbo's dont look to bad..

Correction from earlier:

The only way to run an atmospheric BOV is to either switch to speed density(MAP) or run a blow through setup.

Blow through= MAFS is placed between the Throttle Body and the turbocharger. Then the BOV is placed between the MAFS and the turbocharger.

Yea most factory turbocharged cars use small turbos. It kinda gives them a NA feel. I can see a soccer mom getting in a car with a big turbo. She punches it to go around some cars. At first she says "This thing doesn't even pick up as well as my Suburban!" Then at 4k, she loses traction and slams into oncoming traffic at 14psi. Or no, thats too sad. Alternate ending= She just freaks out, realises she likes it and then proceeds to have an orgasm. And its a MILF.hahahahaha

Is that ssqv type 2 universal?

They are all universal, you just need to get a flange to attach it to the piping.

And Fanatic, so instead of being Intake-MAFS-Turbo-Intercooler Pipe With BOV-Intercooler-Throttle Body-Engine-Exhaust Manifold-Turbo it would be Intake-Turbo-Intercooler Pipe with BOV-Intercooler-MAFS-Throttle Body-Engine, etc.?? If it let's you ventthe BOV, why doesn't everyone do it?

Pretty much all BOVs are universal. They may not sell a kit for your car, but you can weld a flange to your intake piping and your set.

Logik, a lot of people don't do it because MAFS failures have been reported. Some don't trust it because of the increased heat and pressure put on the sensor. It is like most things on cars, it may work for you or it may not. BOV venting is the least of the thrills involved with a turbocharged engine.

And just another piece of advice, the MAFS should be at least 18" away from the compressor inlet. Like before, 8" has worked for people and not for others, so 18" is what always works.

damn lol thats a funny proportion jumping from 8" to 18. I can imagine the guy who started that. He kept on trying 8" and got frustrated so he's like so lets try it way the fuck over here, lets see if you crap out now you little bastard. lol thats just funny.

Cars are freakin wierd. One day something will work, and the next day it doesn't. One day, I will fully understand cars.

What screws the MAFS up(not destroys it, but affects metering ability) is that the compressor creates a swirl effect and well the MAFS likes the air to be unturbulent as possible(if you look at newer cars, they have a honeycomb type screen that straigtens airflow). Another problem is if you run recirc. setup, the air can actually run backwards in the intake. So thats a double whammy on the MAFS's ability to meter air. Although, the recirc. problem will probably just cause annoying stalling and/or backfiring.

yea i have noticed those honeycomb screens...i just thought it was some new and improved technological thing for the better so yea i see what your saying.

I thought recirc solved all problems. lol

It basically does, but it has its requirements as well. Make sure the air enters very close to the compressor and angle it toward the inlet. You'll be fine.

so you route the BOV obviously after the compressor, and then from the BOV you route the recurculating air to where it goes back into the turbo again?

yeah this is quite confusing..

can someone explain vented vs not vented the way logik tried to??
ie. intake-mafs....

recurculating = intake-turbo-bov (b4 the IC im pretty sure) and then the recurculating air goes back into the intake.

atmospheric = intake-turbo-bov (b4 the IC im pretty sure) and then air comes out of the BOV into the atmosphere.

http://www.imagestation.com/album/?id=2135062737

Please forgive the JDM Bling;) I know my engine bay is just soooo slappin', but thats what the guy at Autozone recommended,hahahahahhaahhhaaa

You can see where my BOV is and the hose running under the intake and back the intake. That is a draw through recirculated setup.

If you were to run a blow-through setup, you would move the MAFS to the far side of the BOV(between the BOV and the Throttle body) and simply remove the hose. Good enough?

OK, it's pretty cluttered, but I think I get it, your recirculation hose is the one that passes under the intake pipe, right?

let me show you all my JDM mad tyte coloring skills!! Here the BOV is black with the red hose running under the intake pipe and back in, then the COMP. housing suckes that air from the BOV back in and recurculates...

http://img.photobucket.com/albums/v105/cornelius540/f61dc7ce.jpg

Yeah, ok, that's what I thought...lol, PVC makes me laugh everytime, so ghetto!

PVC is cheap and usefull. too bad i can't make it work for my front mount.

Blow through= MAFS is placed between the Throttle Body and the turbocharger. Then the BOV is placed between the MAFS and the turbocharger.

explain more please.. i'm still very confused.. i think you mixed something up here

wow, blow through setup, whoever thought of that is a genius, or maybe I'm just dumb... but, fanatic if you dont mind me asking, what are all of the other lines connected to your badass pvc piping?

and also, why didnt you run with the blow through setup, any advantages, like responsivness?

ahh you babies let the damm bov vent to atm.. shit so you car stumbles and backfires, but at least you sound cool ! its JDM TYTE

real mean vent into atm..

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