Blow-off out of the Air-filter

[Jspec7m88]

Okay :chicken: so I've stumbled across another mysterious problem...well not necessarily a problem but its weird...my bov...it sucks in air at idle thru the vents, and i've discovered that ALL of my bov pressure blows out(releases) out of my air filter.:nuts: Well i guess this is fairly typical? but the thing that ponders my mind is that when the vacuum hose is ran from the negative part of my throttle body to the BOV(like normal), it doesn't boost NO where near as much as if i run the positive pressure vacuum hose from the throttle body to the bov...so, i guess just give me some feedback as to an explanation!:wavey:

 

[MDCmotorsports]

Um the bov line is supposed to be AFTER the throttle body.

Also, sounds to me like your bov is dead.

 

[miggles]

On a sort of related topic i get a flutter in my airfilter (blitz stainless steel mesh pod) My bov vents (apex twin chamber) to atmo but i get a flutter too coming out my airfilter.Had the flutter when i had stock bov in place too.Ive adjusted bov to hard,soft but still the same.

 

[Jspec7m88]

well see i was power braking it a little w/ the hood popped so i could get a light load on it...and even in positive spool(about 3psi) it would blow off DIRECTLY out of the air filter(my filter is under my headlight so its very obvious) and its as if it goes RIGHT past the bov...also, the vents that go all the way around the bov...when the car is idling, you can feel the air sucking in thru all the vents....unusal? i think so.

i have a K&N air filter and all hardpipes...just about everything under my hood has been replaced(including the motor)

 

[suprarcr89]

you shouldnt be sucking in air at idle but if you have an after market air filter you can hear a fluttering bov sound when you blow off with stock bov...

from what youve told us it sounds like the bov is bad or needs adjusting if aftermarket bov.and the vaccum for the bov should be after the throttle body id hook it up to where the stock bov vaccum hooks up too.

 

[Jspec7m88]

well its the bosch bov first off, and the vacuum lines are all the same as before. the bov does suck in a little at idle, but when you put a load on it, no sound comes from the bov, it all comes from the air filter...i tried adjusting the spring and there was no change.

 

[MDCmotorsports]

Sounds like your bov is backwards then.

 

[Jspec7m88]

hmmm...i'm uhh...pretty sure its not lol. damnit Jon, now i think you've got me ready to put on my shoes and see if putting car parts on at 4 in the morning while its raining outside really effects the way you think...haha. but no, its on correctly. and i'm boostin normally, which is about 12-13...

 

[jester1341]

you both are experiencing Compressor surge...all your boost is aentially working agianst the compressor wheel....i thought my BPV was dead when i bought my car, i swaped for a bosch 110 and had surge still....the cuprit was the vac line all the way at the end where it goes in under the upper intake mani.

1) check your vac lines
2) if possible swap for a known good BOV to see if it is your own

also jspec....

i see this
88 J-Spec 7M. Port n Polished, Bored 3.1, Custom Catless, CT26 rebuilt by HKS, Bosch 110 BOV, NA Cam Gears, Ported Turbo Elbow, MUCH more.

and it should be pointed out the Bosch 110 is NOT a BOV it is a bypass valve. it does make noise["passing off" as i have coined ] that you will hear from the intake since it recirculates. it should also be noted that a bypass valve should never be vented to atmosphere

hope this helps both of you

john