stock blow off valve
 

this probably is a dumb question but would disconnecting the hose from the air bypass valve and plugging the hole to the air box have any negative effects

The only negative effects is that in hard cornering, some oil does seep into the intake track. When that happens, it will shoot some oil out of the BOV and into your engine bay....

Many people have disconnected the ABV from the airbox to hear it like aftermarket BOV's. Just keep in mind that the stock spring in the ABV will vent air at low vacuum.

yep i run mine that way. sometimes you can hear it venting even before you let off the throttle completely. which is what mahjik is talking about with the low vacuum. sounds good and saves you some $$$ if you are just after the sound. the stock BOV is perfectly good if you are running stock or close to stock boost. IMHO

thanx for the help.
so is the advantage of an after market bov is that it can support more boost

Yes, but even the stock one can support up to (and probably past) boost levels of 17 PSI.

If you are staying with the stock twin turbos, the only reason to upgrade the BOV is for personal preference. Kind of the same thing as changing your shift knob; the stock one works, but you want something different. ;)

if you are getting the BOV just for the sound the stock makes more than enough. i was thinking of playing with some kinda whistle attachment, to give it a different sound, but that might be a little too much.

Will installing an aftermarket intake make the stock BOV's more audible?

ill be doing this thursday but i doubt it will ill post up a vid or a sound byte

I would assume so.

I have the stock BOV and no stock air box. The stock BOV can be pretty loud.

Installing an aftermarket intake with hard pipes and DP/catback will make your whole turbo system more audible. You'll hear the air whooshing in through the open-element filter, the shrill of the turbos, the hiss of the BOV punctuated by the staccato of a couple backfires. Personally I love it.

+1:naughty:

guess ill find out tomorow!

the previous posts are dead on. the turbo system is much more audible, you can hear the ABV when shifting, and the spooling is loud as hell. i actually had a cop look away while he was ticketing some chick to see what just drove by 4 lanes away. if you want the bov sound just get an intake, it cleanes up the engine bay, increases performance, and seems to improve reliability somewhat (i have a much smoother idle now)

Stupid question--does an open CRV spit out oil as well?

I suppose it's possible. I haven't seen it happen on the track FD's I've been around though.

I used electrical tape and taped a duck call on mine one time... It was pretty funny.

i think the ABV sounds great personally. although its loudest around 3k rpm, higher up its not as loud, but it does sound great, especially on the highway shifting around 3500 rpm into 5th...sounds great... gets lots of attention too.

Mine were vented to the atmosphere and they were quite loud.

You drive a RX7. Attention is never a problem.

Exactly...

xD true, true. xD

I'm displaying my ignorance again. I've read through the FSM and never see a reference to "Blow off Valve". I've guessed that instead of BOV, Mazda calls it an Air Bypass Valve. Is that correct?

What is the function of the ABV? I have a Greddy Intake so the airbox is gone and I even have a hard time identifying where the ABV would be.

Its the one that the line off the UIM goes to, and its function is to relieve the pressure in the intercooler lines when the throttle snaps shut to avoid compressor surge. When the throttle plates snaps shut, the pressurized air in the intercooler lines will start to build up behind the closed throttle and can start to force the turbo's to spin backwards, which is obviously not good. Technically a BOV is the same, just... is meant to be loud, where as most ABV's are routed back into the system which keeps them quiet.

still waiting for that sound byte :lol:

Thanks for the explanation, it makes sense even to me. As I look at my intake system I see two valves that look like a ABV. There is one that has a vacuum line line runs to the UIM, but there in another that looks just like it with a vacuum line that disappears somewhere under the UIM. Would that be the Charge Relief Valve? If so, what the heck does it do anyway?