cruiser

Last time I had my hood open and had my car running, a friend in the car stepped on the gas a bit and holding it around 3k. I have a vented blow-off and there was quite a lot of air coming through the blowoff valve at steady RPMs and even when giving it more gas.

However my car boosts fine in 12-8-12 boost pattern limiting it with ProfecB.

I just want to know if that is a normal operation, as I'm searching for reasons why I dynoed at only 284hp (not whp)/260tq with my mods at 12psi.

Thanks!

Mahjik

iTrader: (1)

For the stock BOV, that is normal.

cruiser

Q: Why is it wasting all that air ? Is it only under idle ?

Mahjik

iTrader: (1)

Normally that air goes back into the intake stream, by design. That's why you should purchase an aftermarket BOV instead of venting the stock one.

cruiser

Another Q: Would aftermarket BOV then makes the turbos spool faster or reach the max boost sooner ?
There is something missing in this puzzle that I dont understand.

BoOsTin FD

I don't think BOV has anything to do with those 2 things you want. I think you should turn the balance on the profec if you want them to spool faster.

cruiser

What I mean is that air is coming out of blowoff when it shouldnt be (at least IMHO) and that raised the 2 questions above

RxSeven1

iTrader: (2)

mahjik just said thats normal for the stock BOV. if it wasnt vented you wouldnt know it was flowing air. its its not wasting air...im sure theres plenty more

DCrosby

Under Vaccuum you want the excess air to go somewhere.. and not into the intake, under boost you want the pressure, so the BOV, vents excess boost coming from the turbos beeing spun by exhaust and not beeing needed.

Next time have you friend run along side, and hold his hand over the BOV, while you're at WOT and 12 Psi, he won't feel a beath, if he can keep up

TwinTriangles

Isnt that the CRV venting...?

Mahjik

iTrader: (1)

The stock BOV actually blows out some air until there is enough pressure to close the valve.

Snook

iTrader: (12)

just to add.....
the CRV requires a little less vacuum to open than the BOV does they are not the same exact valve

cruiser that is totally normal. You are right at the point where the bov will stay open by reving it like that. Once your car doesnt have a certain amount of vacuum the valve will shut. You can take the valve off of the car and leave the vacuum line on the nipple of the bov. Now suck the air out of the vacuum line until you hear the valve open. Crimp the line with your fingers and now you are able to blow through the valve. now let go of the vacuum line and you cant blow through it again. Get it? it opens only under a certain amount of vacuum. Now the crv takes less of that vacuum to open. Thats just a trick to help understand it better

cruiser

Thanks for clearing it up

Snook

iTrader: (12)

no problem. I had to do a little mcgiver research on my own because I was getting compressor surge on my turbo. I had both the stock crv and bov Td together and I think they just didnt flow enough air. I got a hks ss bov now so we will see.

duboisr

The stock valves open at 4 inches vacuum , you idle at more than that so untill the car draws less than 4 inches vacuum the valve is open . My mechanic has changed the springs in them so they are closed untill 17 inches vacuum . you go more then 17 inches when you let off the throttle at higher rpm than idle . This change keeps the idle air going to the engine at low rpm when you need it . He has gone to two HKS ss valves this week ,taking the two plastic valves out (non-seq ) .

Snook

iTrader: (12)

duboisr I emailed you did you get it?
I had a question for you try to get back with me I cant message you through the forum since you have that turned off

thanks