zoomzoomkid

i was helping my brother with his car today, the air pump line that runs into that intake manifold. blew. so we replaced it. and then took it for a drive and we keep hearing the whoosss whens hes on the gas? sounds like its sucking alot of air in. but i think that the stock bov it seeping and not holding pressure? anyone have a guess? sorry if am being vage. thanks for reading this

weetbix13

charge relefi valve should make noise until 4500rpm then shut off.
if that is venting into the engine bay then you'll hear it.

dgeesaman

iTrader: (7)

I'll bet it's a plain old boost leak. Start at the rubber coupler closest to the turbos - remove it, turn it inside out, etc looking HARD for leaks. If none, check out the rest on the intake.

Dave

neopj3

It's my car. When I took off the intake pipe from the turbo to the intake(primary i guess, it's the one on top) this little cardboard thing crumbled to pieces. but the sound and a loss of power happened before that. after work i'll check all the boost pipes. it really sounds like the bov is closed then opens and it won't close and hold pressure. it revs up but won't produce the neck snapping force i'm used too. that's when i found that the air pump hose blew. i've got an apexi intake and it's really loud (wooosh sound). i'll replace the vac line to that bov (to the intake on the top) and see if that helps.

Rufio

im having a similar problem...i hear the sound before i start boosting, starting at about 4 Vac. PSI...i dont have a boost leak, are you suppose to hear it a little before u start boosting?

neopj3

my friend is making me a custom gauge pod for me and he's got my boost gauge. my brother pointed out to me that the bov off the y-pipe was loose when we installed the apexi intakes. so i'll be looking at replacing that if it's hard or brittle. i'm useing heater hose from pep boys and nice screw types hose clamps. i hope that i don't have to replace all my boost piping with hard pipes....

quicksilver_rx7

If you have the stock twins, you have the CRV (Charge Relief Valve) and the CCV (Charge Control Valve) valves unplugged from the airbox (vented to atmosphere) and you cruise along without boosting, you will hear a constant wooshing sound. As soon as you floor the car and start boosting, the valve closes and boost rises.

quicksilver_rx7

Most of the time, the problem lies within the rubber couplers. The CRV & CCV are pretty solid units. I have yet to see one leak. The intake hose for the primary turbo will, over time, weaken and develop a hole or crack. The intercooler piping doesn't really give too much of a problem.

Joe

neopj3

thanks, i'll take the hose with me tomarrow and replace what i can get my big hands on. I figured the bov's to be pretty solid, but this cars been sittin for a while (like 2-3 years! other owners never knew what they had!) I expect things will need to be replaced, like the air pump hose and the intake, dp,cat,midpipe,exhaust,ect. what the hell was that little piece of pressed paper in my intake near the top turbo (primary?). the dang thing just fell apart! it's before the turbo, so i'm thinking i'll be alright untill i replace the stock piping with alummin, or stainless pipes. the rubber hose on the air pump crummbled in my hands as i pulled it off, maybe the same happened with the hose for the bov?

neopj3

can i use fuel line for a temp solution for thevac lines to the bov?

Stix37867

iTrader: (1)

I'm not really sure what your problem is but i do know that the stock bov does vent boost. It starts to open at 8psi and is fully open at about 11-12psi. When is the boost gauge getting installed? That'll help you figure out what your problem is.

neopj3

as soon as my buddy finishs the pod. it's going to mount in the center channel speaker area. the bov is not supposed to vent as you accelerate right? it's open all the time, or the bov hose is bad and i've got a crack in it. i'm lossing power.

Bad_Karma7

If you're in a pinch, go get some vacuum hose from autoparts store.

Stix37867

iTrader: (1)

All the BOV knows to do is to start venting at 8psi. It shouldn't vent any other time.

JDawG707

is there anyway i can just plug up teh CRV? i have the same noise and its hella nnoying, ive somewhat learned how to drive with it(blast the music helal loud)

Stix37867

iTrader: (1)

NO! You don't want to do that. That lets out any boost the the secondary turbo makes and if you plug it, all that boost has nowhere to go except back to the turbo. Do you have it vented or something cause i can never hear mine?

JDawG707

mines vented....im tryn to buy some 90degree 1/2inch pipes so i can have it vented back into my intakes...but so far no like finding the things anyone have any ideas on what i could do to shut it UP

Stix37867

iTrader: (1)

Ok i understand now. You could try to find some radiator hose that's the same size and has the angles you need. That's what i did for my BOV.

JDawG707

ill look at HOmedepot this weeekend for them...how much are they usally? or can i just find them at a local kragen, and also u got any pics? cause i want to kno what u did JBweld?

neopj3

i got my heater hose (3/4") from pep boys. it's like .80 per foot. i don't think you want to use jbweld unless your trying to make it work with a stock intake. other wise use hose clamps, they're really cheap at lowes where i work (like .50).

dgeesaman

iTrader: (7)

No, the BOV (Air Bypass Valve) opens when the manifold turns to vacuum. So when you let off the throttle from boost, and there is vacuum between the throttle plates and engine chamber, it opens and vents boost.

quicksilver_rx7

This would probably be a good place for you to learn how the RX-7 controls boost with the stock setup.

Stix37867

iTrader: (1)

Have you either of you guys actually tested the stock BOV's. It's common sense that they open when it gets vaccum. But when i tested it with a pressure tester, as soon as the tester hit 8 or more psi, it was open. If you can try it, i suggest you do. I'd say Mazda made it like that as a secondary precaution like a pop off valve.

Edit: As for my statement about it only opening at 8psi, i figured it was implied that everyone nows it opens when it sees vacuum.

neopj3

mine opens under wide open throttle. i've got some vac hose and some hose to replace the factory bov hose.

dgeesaman

iTrader: (7)

If it's opening under throttle, replace it. I have a low mileage CRV and ABV sitting here on my desk that hold 15psi without a problem. If you disconnect the ABV from the intake you should not hear it whooshing out any air when you're boosting.

Dave