"Vent to atmosphere or not to vent to atmosphere..."
08-13-2009, 12:02 PM
#1
"Vent to atmosphere or not to vent to atmosphere..."
...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?
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?
08-13-2009, 01:46 PM
#2
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.
08-13-2009, 02:53 PM
#6
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.
Relocate it to where?
I also read some where that venting to atmosphere makes you car run like ****? is that true?
08-13-2009, 05:55 PM
#9
Senior Member
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.
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.
08-13-2009, 06:13 PM
#11
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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.
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.
Last edited by bowtie32; 08-13-2009 at 06:13 PM. Reason: Automerged Doublepost
08-13-2009, 06:43 PM
#14
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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
08-13-2009, 06:45 PM
#15
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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
08-13-2009, 06:47 PM
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That is true my friend but if you got a good enough intercooler you will never notice the difference in the temp.
08-13-2009, 08:17 PM
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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.
08-13-2009, 09:06 PM
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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.
08-13-2009, 09:09 PM
#20
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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
08-13-2009, 10:34 PM
#21
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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.
08-13-2009, 11:42 PM
#22
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.
08-14-2009, 04:59 PM
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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.
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
08-14-2009, 05:46 PM
#24
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
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.
08-14-2009, 05:59 PM
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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 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.
also i do my own work on my vehicles. i work for gm and im a gm trained mechanic.