hey, i've been around a couple of forums and i've heard on this one maxima forum that a bypass valve jus puts all the air back into the cycle of the turbo and the bov lets it go into the atmosphere..well my question is which is better ? the reason why i'm asking is because i'd rather people not know i'm turbo ( dunno how easy that will be ) but i wanted to paint the IC black and keep the noise level down as much as possible without losing any hp needlessly. so will one be more beneficial as far keeping power ? i dont really understand the diff unless the explanation i got was pretty much it...TIA


[Modified by SleepersOwn, 12:04 AM 1/6/2003]

 

I was never aware there was a difference between the two.

 

IIRC a bypass tends to be less efficient on cars running at higher boost levels and they are also more ideal for cars with MAF systems.

IMO you should just find a really quiet BOV...people are gonna know you're FI when they hear that turbo whine.

EDIT: and pretty much the differences are what you have been told, BOV vents to the atmosphere, bypass gets vented back into the intake.


[Modified by BlueShadow, 9:36 PM 1/5/2003]

 

On a MAF syatem you can just vent before the intercooler to avoid tickling the sensor though. So it's the same valve just different way of routing it?

 

If you want to keep it sleeper. Route the BOV air back into the intake. It'll be silence that way. Most cars that some with stock turbo's are done this way.

You can't really quiet the turbo spooling up though


[Modified by machaf, 10:41 PM 1/5/2003]

 

Thanx for the info guys... yea i know that i couldnt get away with but so much of the " sleeper " effect, i'm just trying to learn all the things i can do to stop needless noise, i figure with the music kinda loud they cant really hear too much. Anyway THANX AGAIN GUYS

EDIT: would anyone happen to know of any fairly quiet BOV's ?


[Modified by SleepersOwn, 2:33 PM 1/7/2003]

 

Actually I believe a bypass valve is intended to be used to help protect against overboosting, whereas the BOV just vents pressure between shifts to prevent compressor surge. Unless I'm thinking of something else, that's what a bypass is for (I know people use them in place of BOVs also though).

You can always get a BOV with a flange so you can connect a hose from it to the turbo intake, that should quiet it down quite a bit. I will probably do this someday when I change to a different BOV.

 

If we are talking about a bypass valve wasnt the original plan not to let the intake suck in water. i didnt know there was another way it was used.

 

I think you're are thinking about the AEM bypass valve for CAI's...we are talking about a different type of bypass valve (compressor bypass valve). The one we're talking about is almost similar to a blow off valve.

 

AH could u have both Bypass valve and a BOV?

Prob not necesary jw if it could be done and if it would work better.


[Modified by 5thgenhybrid, 3:34 PM 1/7/2003]

 

Why would you want to use a bypass valve (which is just a BOV that routes air back into the intake) and use a BOV that vents to the open air?

Two BOVs would make sense, or 2 bypass valves would make sense too...but not one of each. One of each isn't necessary.

 

a blowoff valve on a turbo MAF car should recirculate back into the intake stream. the MAF is usually placed inline with the comp inlet, the ecu knows how much air is present all the time. the valve then recirculates the air behind the MAF since its already been acounted for. i used to run my car (turbo nissan) with the blowoff venting to atmoshpere, and it ran like ***. whenever it "blew off" the car would run really rich, stumble, and then backfire.

and yes, a recirculating valve is a lot quiter, but u can still hear it.


[Modified by javierb14, 6:47 PM 1/7/2003]