does anyone know if you should vent the BOV to the intake or into the air? does it make a power difference? i have seen cars set up both ways, but which is better.


thanks. scott k.

Vent if you are running a VPC or a stand-alone. If you're still using the MAS, venting will hurt performance, thus, don't vent.



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1993 Eagle Talon Tsi
12.28@113.45mph
Missing In Traction

What ever you do dont try and vent to the atmosphere if u are running a stock system.. this happend to me on Saturday Night.. i took off the UIC and 3" intake to do some painting ect.. when i put it all back together i forgot to hook up one of the BOV lines so i was venting to the atmosphere,, i was getting very irratic idle, and the check engine light came on and went off.. the car would also stall at lights.. Venting is not for me..

just letting u know what happens on a stock system

L8R

Rob, your big problem wasn't venting to atmosphere, it was that the other end of the BOV tube before the turbo was letting air in that didn't go throught the MAS. It was running like the MAS wasn't hooked up at all.

If you vent into the air, (and get that cool sound!) won't you get turbo lag? The bov vents the air back to the turbo, thus reducing lag, correct?

Marty

The reason I ask is because I can't tell the difference, other then a psssssssssssst noise. In Sport Compact mag, they did a write up about a GSX with mods. Who ever the DSM guru on project said "Venting hot o2 back into the intake doesn't equal performance", or something along those lines.

Thanks for letting me vent my question, as for my car, she will be plugged up when its not so cold outside. =)

But the air has already passed through the intercooler.... so it would be warm, but not hot.
It just helps keep the turbo spooled during shifts, right? I dunno.

M.

To be honest, I don't think it does much for keeping the turbo spooled. The air just has to be routed away from the TB so it doesn't hit the throttle plate and come back the other which would complete disrupt the flow and the intake was the most convenient/logical place to do it.

I have mine vented to the atmosphere and it doesn't make a difference one way or the other in terms of lag (although maybe it would if I had a bigger turbo?).

Either way, if you can live without the cool sounds, you're better off venting it back to the intake, since the MAS has already counted the air, and if you spit it out into the atmosphere it thinks it has more air than it does, and gives a bit too much fuel when you get back on the gas.

Jeff Mitchell

Also, if all you have is the bov venting, besides running pig rich, you'll also lose your cruise control. Well, for me anyways. I say vent back to intake. Do as I say, not as I do.

Absolutely!

If you want to vent with stock MAS, you have to have this. It functions like an S-AFC plus it allows you to vent.

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Teal '92 AWD TSi

Callran,

That's weird! The cruise control and venting should have nothing to do with one another.

Like I said I'm vented and I definitely don't have that problem.

Maybe a wire got clipped or you blew a fuse or something?

Jeff Mitchell

Actually Jeff, The cruise control still works, I just can't use it. Let say I have it set at 100, if it drops below that, the car will accelerate at which point the bov will begin its slow vent. This is where I lose boost and speed drops so I will be jumping between 90 and 100.
Maybe it's just on ATs. Well, at least my idle is rock steady. I would vent back to the intake if I didn't have that 3" intake.

Venting w/o shifting. COOL.

[This message has been edited by Callran Woo (edited January 16, 2001).]

Turbo is spooled from the exhaust side, NOT the compressor. It wont hinder performance, at the least it would make it better....reason...hooked up your compressing the air again, its warm, now you make it realy hot. Venting you abviously wouldnt do this, and you'd cool your cylinders by going rich inbetween shifts. The only problem is that it goes so rich it fluds the motor, causing a sputter.
To be honest, I dont do it, I got a sputter(or buck) when going REALY fast on the highway when I was venting, generally not good at 200+.

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91 Laser turbo White, FWD
Profec A, baby
"DSM TURBO"
"OSOFAST"
BLOWN MOTOR!!!!!

Callran,

OK, that makes a whole lot more sense. I'm not going to feel bad for you if you blame it on the 3" intake though.

Jeff Mitchell