...that is the question.

I've read a whole bunch of threads on what people do whether they recirculate the air or they vent it to the atmosphere. What are the pros and cons of each?

 

The only way to vent to the atmosphere correctly is to relocate the maf. There are no cons to either if they are done right.recirculating is pretty much the same as running the bpv and will be quieter then venting to the atmosphere.a bov isn't really needed on these cars unless you upgrade the turbo really though.

 

Just get a CAI. Makes the sound just as loud

 

vent that bit
vent that bit

 

Recirculating can help with spool time.

Atmosphere just sounds cool lol.

 

Relocate it to where?

I also read some where that venting to atmosphere makes you car run like ****? is that true?

 

Your car will adjust to it, it wont be perfect but you will not be hurting it.

 

It will adjust to what? Which ever I decide to do? You've got the dejon setup I'm looking to get. How you liking that?

 

After the bov.

I don't see how, the compressor wheel is spinning at 100,000 rpm and little puff of air wont do squat to it. Lot of people say this, but i'd love to see some proof to go along with it.

 

Sooooo then there's no real difference? Other than venting to atmosphere makes a cool sound and the other one, not so much...?

 

It's best to have it vent before the maf sensor so the air fuel ratio is correct.

But either way it workS out fine. I've heard it's almost pointless to buy a BOV and have it recirculate because u won't hear it really and our stock lnfs already do that.

 

With an intake your by-pass valve is just as loud. I was going to get a BOV but im happy with the sound the stock makes. very loud.

 

oh yes the loader the better. i like to be neck and neck in a race just so they can hear the performance before i leave them listening to my exhaust. :P

 

The MAF is not affected by the bypass valve people the recirc'd air is recirculated within the turbo and the air doesnt come even close to the maf sensor!!!!!!! the map sensor is however. search i got a write up on what happens and what needs to be done when going to atmosphere bov. i got atmosphere with not a single issue once tuned runs amazing and sounds amazing and turns every head. and i went atmosphere so i can put in a gt28 or gt30 turbo. also our turbos spool so fast anyways it dont matter on type of bov. its getting annoying how ppl keep assuming that the maf need reloating and other dumb ****. you can not relocate it. it needsto stay in the intake in an addiquite location. you will get DTC's and running issues and improper data with tuning and all kinds of stuff if notin correct location. MAF onlymeasures the volume and density of the air the in being drawn in and there is also a temp sensor on the maf. THE MAF IS LOCATED ON THE INTAKE WAY BEFORE THE TURBO. THE MAP IS LOCATED IN THE INTAKE MANIFOLD AFTER THE THROTTLE BODY

 

wouldnt recirculating it creat more heat? if it runs thru the turbo and then goes thru it again wouldnt it just get hotter? f'that i say get rid of all the hot air as possable

 

That is true my friend but if you got a good enough intercooler you will never notice the difference in the temp.

 

Damn alright. I'm looking forward to getting my dejon intake soon. I appreciate all the help and info guys. Thanks

 

I have dejons intake with Synapse Engineerings BOV. I needed a custom 1.25" recirc fitting welded on the intake so i could recirc it. At first i vented it to atmosphere and the car would jerk once i vented off because of the jacked up A/F. It was drivable but not fun. Now that i recirc it, it drives just like stock with enough, not extreme BOV sound.

 

Im also guessing you were not tuned for atmosphereic bov that y u were getting rich conditions.

 

Yes, thats correct, i was NOT tuned for it. Some other guys were able to get better results with different BOVs and no tuning. I think Synapse Engineering BOV had a higher flow/discharge rate causing a quicker/more severe rich A/F than the other BOV's. Its all good now though running it in recirc

 

You're creating a boost leak during a shift, how do you tune for that condition during a shift? There's nothing in the ecm that you can change that will fix this. This is exactly the reason why you should move the maf after the bov so that any air that the bov releases isn't metered by the maf. Ask anyone whose been in the turbo game for a while and they'll tell you the same thing.

 

well some people are having problems with the cars venting to atmosphere and some arent. it seems the people with the turbo xs and iforget which other arent. my sensor will be located right before the throttle body. ill have the piping and the tial in about a week or so. let you know how everything goes.

 

Yet let us know the out come but if i were you i would put it at least before the pressure sensor in the cold pipe.

i wounder if a guy was to cut the maf sensor flange out of their aftermarket intake and weld it into the cold pipe and get the intake refabbed to not have the sensor location there. i got the hahn intake and i can easily take the intake piece and get a new one rebent without the flange on there.. hmmmmm


But i dont know if i want to do this because im not having issues with mine rite now.
It would create the maf to get more accurate readings for the ecm

 

I'm having trouble understanding some of what you said, but I thought I'd try to clarify some things... so sorry if some of this is redundant.

The whole reason that the MAF is part of the problem with a BOV is because it's in the intake. That's why people are saying that it may need to be relocated. If you blow off the air before the MAF, then the car doesn't care because it never saw the air that you blew off to begin with. The charge piping or location like that comes to mind as far a good relocation place. You'd need to tune for the new pipe diameter. It's a good place also because the piping is so straight there (no skew!.. smooth, even flow )

What happens is the MAF tells the ECU how much air the engine has coming its way. If you use a BOV then some of the air disappears out of the system and then when it gets to the engine, there isn't as much air as the MAF told it there was, it goes rich, and the ECU is like .

Also, did you do the charge pipes on your car? You should've noticed the MAP sensor right there on the cold side pipe. After the throttle body/intake manifold, the air's in the engine.

 

The map sensor is in the manifold not the chargepipes the is a boost pressure and temp sensor for ecm reference on the turbos performance and for over boost and under boost conditions as wells at the intake sensor temp #2 intake temp #1 is in the maf sensor. Also that is another issue is the piping size is different and im not even sure the charge piping is big enough to house the sensor the maf sensor is pretty long it may fit never realy measured its length and you would have to calibrate it for the small diameter piping.


also i do my own work on my vehicles. i work for gm and im a gm trained mechanic.