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Bov Before Or After Fmic

Gongts4

By Gongts4,
in Engines & Forced Induction

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Gongts4 Explorer

Gongts4

Posted
Posted

jst having to make up some custom cooler piping for my setup, and was wondering if anyone had a good argument for where i should place my bov. atm im slightly confused as my mate has his bov jst after the turbo before the cooler, he does this because he belives it does a better job of protecting the turbo from spining backwards......but if this is true why do you see nissan placing there bov's after the cooler, is that because there plumbing colder air back to the turbo...........or does it not make a difference where she goes.....any ideas guys.. :D

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Mr. Untouchable Experienced

Mr. Untouchable

Posted
Posted

Ive always run them as close to the throtle body as possible ie 6-8 inches away.

and as for being "better" for the turbo to place the BOV close to the turbo, mmm cant really see how its going to make it better.

what does matter is plumbing wasted air back into the intake pipe after the AFM.

cheers

Bennett Mentor

Bennett

Posted
Posted

Turbos NEVER spin backwards. Load of shit. What sort of blow off valve is it? If its aftermarket you might want to hide it down near the cooler so cops dont give you trouble unless you feel the need to show it off. I prefer plumback blow off valves personally and would put it in the stock nissan position unless you have a front facing plenum etc.

Hell Fire Collaborator

Hell Fire

Posted
Posted (edited)

Closer to the throttle body you've got the air flowing one direction only, if you put it at the other end you end up with air moving back and forward through the IC, possibly having your colder air in the system reabsorb some of the heat as the pressure drops and becomes less dense.

Suppose with a larger IC it will hold a pretty fair capacity, but keep in mind at 3000 RPM your engine is sucking in over 0.075m3 a sec (150 CFMish), so whatever air sits in the IC will be gone pretty quickly once you get back on throttle. May not matter so much until you're chasing big power/response but if you're going to do it once, closer to the throttle body is likely to do better.

Edited by Hell Fire
Gongts4 Explorer

Gongts4

Posted
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Posted

ok so after taking all this info in, i've decided that i am placing my BOV before the cooler only because it makes it alot easier to plumb it back. the way i have riged it up is the bov well be in an enclosed box where the air filter is housed keeping under bonnet temps out, also the cooler and air filter piping to the turbo have been wrapped in heat resitant tape, hopefully this well help keep the air going to the turbo fairly dense.... also im sticking with my stock bov , it does a good job , sounds good and is legal too.

SLAPS Rising Star

SLAPS

Posted
Posted

Sell the bov.

Many cars out there (street/rally/grip/drift) that run without them and have no reliability issues.

The response gained when running no bov out weighs any driveability or if it concerns you emission negatives.

I've ran 20psi for a good 30k and not one issue.

Prior I had run 100,000km's on the std ceramic turbo @ 1bar and again no issues.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

^^ please dont start the 'gain' rubbish.

End of the day, the stock ECU expects a BOV to be there. Emissions also required it.

Using cars that are not street registered and working within the confines of the law are not valid examples

Bennett Mentor

Bennett

Posted
Posted

I have a power fc tuned with the blow off valve off as the intake pipe im using at the moment doesnt have an inlet for the plumback. The car runs the same as with the stock ecu in (well for me anyway). It almost stalls when you press the clutch after being in gear at high revs etc. Its also a lot more jerky on gear changes. I have learned to deal with it but it deffinately is different the way the cars drives and ill be putting the bov back on as soon as i can be bothered to make up a new intake pipe.

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