Do you guys run your BOV on the hot side or the cold side?

[SketchyRollin564]

I went ahead and bought a cold pipe with a greddy flange for my BOV. I was looking around enjuku this morning and i noticed, they sell the hot pipes with the BOV flange on them, and the cold pipes with no flanges

However ive seen SR setups with the BOV on the Cold side, so i dont think its a big deal

I do know that its easyer to recirculate air with it on the hot side, but ive heard the theory that when the charged air bounces off the closer throttle body, with the BOV being on the cold pipe, it can escape quicker

Just wanted to see peoples opinions on why to run the BOV on one side or the other

[Razi]

I run mine on the hot side, have it recirc'd, BOV response is quick and I don't feel any sort of lag at all.

[zerepdivad]

Hot side on my ka-t.

[mattblancarte]

Hot side on my car.

Cold side should technically give you slightly better response. Haven't tried it for myself, though.

[OM3GA]

Golly another thread aboot this.

Hotside when it goes on.

[White Comet]

cold side mostly for ease of running vac line

[meet07]

Cold side is where it i suppose to go..Closer to the tb *hent* the tb clsoes and the air reverses at the tb and the air coming from the turbo is already moving that direction.

I never knew why Nissan puts them on the hot side. The bov is a long way away from the tb. I actually put the bov on both sides and it didnt blow of on its softest setting when placed on the hot side. After relocating the bov/pipe to the cold side it worked perfectly...

Cold side,cold side,cold side!!

[Morph]

I got mine on the hot side.

[frftw]

cold side gets faster response hot side gets the long wooooooosh. just depends wht u want, performance or sound?

[scotty-2-forty]

A lot of people say it's best to install it close to the throttle body since that's where the back-pressure forms first when the butterfly is closed. Yet others will tell you that it's better to install it as close to turbo as possible. That way, the BOV is venting hot air instead of cold, so that the inlet pipes after the intercooler still contain cool air. It really doesn't matter as the benefits are miniscule. Proper adjustment is key to preventing a back flow of air toward the spinning turbines, which produces that fluttering sound. Just be careful when mounting close to the turbo however, because there is often a measurable pressure drop between the turbo and throttle body, particularly as the RPMs build. I run on both sides as a precaution under heavy load. I've been dubbed the "hissing hyena" by some friends due to the two different sounding BOVs ... when dialed in and adjusted properly however, it's both beneficial to reducing turbo flutter, and evil as hell sounding. Just my findings.

[Bumnah]

Hot side. Easier to recirculate.

[Jadesr20det]

Cold side on mine gets better reponse than my buddy who has his on the hot side. His is louder though. Personal preference

[Tyler]

i run mine hotside on my KA-t vented to atmosphere with a blow thru z32 maf and driveabiltity is perfect, i have never driven with one on the cold side tho so i cant compare.

in theory it would make sense to have it on the cold side because its blowing off after the intercooler, thus keeping the core pressurized for less lag. i would assume the difference in negligible tho and only really noticeable with smaller t25 sized turbos and big intercoolers.

[ZootedS13]

my friend and i have pretty much the same setup except i run mine on the cold side and he runs his on the hot. we have the same bov but his sounds more like a chirp when it opens and mine is more of a whoosh sound.

[scotty-2-forty]

my friend and i have pretty much the same setup except i run mine on the cold side and he runs his on the hot. we have the same bov but his sounds more like a chirp when it opens and mine is more of a whoosh sound.

Yep, that's the 'flutter' sound of air pressure backing up to the spinning turbine in it's desperate attempt to escape the wrong way. BOVs themselves do not make the chirping sound, they amplify the fluttering, thus why some of them have 'horns'. Performance wise, the less flutter the better, but yes the sound can be cool and quite negligible.

[leesredgt]

cold side!

[biggie]

Since everyone else is doing it...

Hot side, but I've got blow through setup, so MAF is on Cold.

[zach-Ka]

Hot, but plan on relocating to cold.,.

[S13Teddy]

I do not run one at all.

[ashibah83]

I do not run one at all.

^ real man, compressor surge is where its at!!

im going to run mine on the hot side as my maf needs to be after the BOV( blow through KA-T) but i have a synapse so im not worried about response

[Didderson]

Cold side because I'm not recirculating so the pressure builds at the TB first, and helps keep momentum throughout the system flow toward the TB continually.

I should add an apexi safc2 will help correct MAF air signal when BOV actuates but it's still not as good as a tune. Who says fireballs aren't cool anyway.

Hidden bov location when you look under the hood Old pic:
Modified by Didderson at 4:00 PM 2/23/2010

[SketchyRollin564]

wow, lots of decent answers

that dual BOV setup looks MEAN haha id love to hear how that sounds

So basically you get less lag with it on the cold side, but you also dont get lag on the hot side so long as you recirculate the air....

Ive heard its not good to vent the air to the atmosphere because less air is going into the engine than the MAF thinks there really is, and you can flood your engine or somthing like that

[Tyler]

^^ you can vent to atm if you go blow thru, cause the air being blown off has not yet been read by the MAF

[S13Teddy]

Whatever you do, make sure to recirculate it.

[White Comet]

i ran mine open to the atmospere with a mafs and no tune, ran with no problems

[Jadesr20det]

I run open and and on cold side and it I dont have any issues

[boriquaS13]

I vent my bov also no issues here

[SketchyRollin564]

Whatever you do, make sure to recirculate it.

Why do you say that?Im asking because ive seen plenty of setups that vent

[Justin35ll]

Mine has always been vented and never stalled on me. Rpms drop to about 5 - 600 then go back up that's all.

Recirculated it once just to see how it was and the rpms didnt drop

Mines on the hot side now, but I plan on relocating it to the cold side right after the fmic sticking out the front bumper

[AAV240sx]

Why do you say that?Im asking because ive seen plenty of setups that vent

This is knowledge from what I remember reading in a article a few years ago, so somebody please correct me if I'm wrong.

On a regular maf setup, with a recirculated bov, it is measuring a certain amount air going into the motor and telling the ecu to dump fuel accordingly.

On a car with a vented bov without the proper tuning or a blow by setup, the ecu thinks a certain amount of air is going in and adjusts the fuel accordingly. However, since the air has been vented, the readings taken by the maf will be off and the car won't run as efficiently.

So even though the motor may run perfectly fine, it may have lost a horsepower or two.