What´s the difference between releasing the pressure to the atm and back to the intake?
BOV to intake Vs BOV to atmosphere
diogo
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the difference is that when u vent back into the intake the air gets counted by the mas which is normal for the car...now if u vent to the atmosphere the air doesnt get counted which makes the car run rich and stall at idle if u dun have a stiff enuf spring in your bov....from what i know...the only bovs that u can vent to the atmosphere r aftermarket ones that have stiff springs or chambers...whatever they use...hope this helps
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Whether or not your car will run rich on shifts with the BOV vented to the atmosphere doesn't depend on the BOV itself. The problem is that the air has already been counted by the MAS so fuel is being added for it. When you shift and let that air out the fuel is still going into the engine for it. The only way around this is to run a speed density system like the VPC. If you are using the stock air metering set up you can't vent to the atmosphere without ill effects.
There's really no advantage venting to the atmosphere when your are running the stock configuration. Racers vent to the atmosphere because :
1. You release the air quicker when dumping into the atmosphere.
2. Because their engine management computer can handle it.
3. Because it's either impossible or impractical to route air from the BOV back to the intake.
If you check the parts name for the valve, it's a compressor bypass valve, which means that it is meant to be vented back into the intake. The 1G CBV is often erroneously refered to as a BOV. By definitions, BOV's dump to atmosphere and CBV's vent back into the intake. Of course, often the only difference between making the 1G CBV into a BOV is to disconnect the vent hose.
If sound is the only reason why someone is venting to the atmosphere, then I believe that is a product on the market that would suit their needs...it's an electronic BOV noise generator.
1. You release the air quicker when dumping into the atmosphere.
2. Because their engine management computer can handle it.
3. Because it's either impossible or impractical to route air from the BOV back to the intake.
If you check the parts name for the valve, it's a compressor bypass valve, which means that it is meant to be vented back into the intake. The 1G CBV is often erroneously refered to as a BOV. By definitions, BOV's dump to atmosphere and CBV's vent back into the intake. Of course, often the only difference between making the 1G CBV into a BOV is to disconnect the vent hose.
If sound is the only reason why someone is venting to the atmosphere, then I believe that is a product on the market that would suit their needs...it's an electronic BOV noise generator.
Jehu said " a product on the market that would suit their needs...it's an electronic BOV noise generator."
I'VE GOT IT I'VE GOT IT!!
Now I know how I am going to make my first Million!!
Tapes of fast cars, turbos and maybe a BOV with a big O' WHOOOSH!!!
For only $19.95 you can have your very own tape or ONLY $24.99 for a CD!!!
O this is going to be good!!!
hehehehehe
Bill Marino
Hole Shot Performance
I'VE GOT IT I'VE GOT IT!!
Now I know how I am going to make my first Million!!
Tapes of fast cars, turbos and maybe a BOV with a big O' WHOOOSH!!!
For only $19.95 you can have your very own tape or ONLY $24.99 for a CD!!!
O this is going to be good!!!
hehehehehe
Bill Marino
Hole Shot Performance
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The hondas will be lining up at your door Bill.
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Hahaha that funny... I've seen a couple Hondas and Acuras down here at the races with a front mount but no intercooler piping... weird huh. HAhaha those guys are so silly.
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when venting the air into the atm. or into the intake the only real diff. is when it goes into the intake the turbo slows down slowly because the bov air is still spinning it ... when you dump it into the atm. you are losing the air to still spin it so at hardly giving it any gas the car will sputter because the turbo is spinning and then just stopping when you change gears at low rpms is when you have real problems and plus it gives you the real bov sound and when you dump it into the intake it quitens the sound. i have the turboxs type h and it goes into the atm. and the car runs fine .. it is just what your preferance is to really be loud or to be quite
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While venting the cbv to the intake may help keep the turbo spinning slightly I think you are way off on why the car stumbles on shifts. It is because of a rich condition in between shifts because of the missing metered air.
That's the way I understand it too, greenstreak. I think that's right on the money...greenstreak said:
There are many aftermarket bov's that make noise, but the noise doesn't make you go any faster, hehe. I'm pretty sure it will cause a stumble, decreasing performance. My 1g cbv is loud enough @ 16 psi that I can hear it over the exhaust.
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Right on Van! My 1G CBV (I am trying to use that now instead of BOV ) is plenty loud even with it routed back to the intake. I don't need anything flashy...its all about bang for the buck!
) is plenty loud even with it routed back to the intake. I don't need anything flashy...its all about bang for the buck!
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OK, now I am no Eclipse wizard here BUT it sems to me that you guys may be wrong. NOW before I get dogged please read what I have to say. If you look at your cars, where is the tube located which dumps the air back into your incoming air???? I beleive it is Behind the Air Mas Sensor, therefore that air isnt being read after all huh??? SO I beleive that DarkKnight is correct in saying that its from slow spool. Check it out yourselves and tell me how the air could possibly be known as there when the air mas isnt reading it?? Its behind the Air Mas when it returns therefore isnt read. Thats my opinion on it. Maybe itll help. Thanks
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You guys may be somewhat right but some of the stagger or pause comes from the air not being there as well. There may be a difference in the fuel but i don't think there is , but there is also a difference in the air which was there. The aftermarket BOV's for the Eclipse make a cool noise yes, but they do help the performance of our cars. I've seen time slips of Eclipses w/ only Intakes and BOV's and the ones w/ BOV's turn faster times than the ones w/o them. SO I would have to say that they do help. Also if an aftermarket BOV doesnt help the car, then why do they make them, and why do the fastest ones run aftermarket BOV's?? Answer that question. BUT you guys are somewhat right about the fuel but as I said before, the air has something to do w/ it as well.Plus the air from the BOV is coming in from behind the air mass so it is not afecting the air mass which controlls the fuel.And i was meaning for it to sputter when you have the car in 1st and give it a little gas at low rpms, not changing gears at low rpms.
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exactly 1faststealth thanks for the support
Heh heh, time to jump in here. Lets do this one point at a time.
Okay 1faststealth.
Yes, the tube vents AFTER the mass air. BUT, how did the air get to the CBV in the first place? Through the mass air. Any air you have in the intake at any point after the MAS to the intake manifold have ALL been counted by the MAS, so when you vent pre-counted air back into the intake, you do not need to count it again. Now if you vent this counted air out to atmosphere, the computer is injecting the required amount of fuel for the air that it counted. It doesn't know that a portion has been vented, hence you go rich when the BOV vents. And that's where you get the stumble.
Now, if you think that it is due to the CBV spinning the wheel, why does the stumbling go away when a VPC is installed and a BOV is used? Because now the systems uses a MAP sensor that basically gives a measure of the amount of air right at the intake manifold. So you can blow off half your ingested air, and the VPC will still put in the right amount of fuel.
You see 2G eclipses running better with aftermarket BOVs because the stock 2G CBVs are plastic pieces that do not hold boost very well. I noticed a 2 psi increase when I swapped out the IC pipe and CBV with a hard-pipe and 1G CBV.
Of course it's going to run better.
The reason you get sputtering when you give it a little gas at low RPMS is because the BOVs somtime partially open with a vacumn signal, and lets in unmetered air. Now there's more air then the computer knows, so it goes lean and you get stuttering. ANY component of the intake AFTER the MAS DOES affect the car. For example, you have a leak, you'll run too rich, and you'll stutter.
Point is, our stock MAS system does not work well with BOVs. If you have a MAP system it's a different story. Yes, the fastest cars around use aftermarket BOVs, but what kind of computer system are they running? Stand alone I'm sure. And at the pressures they are running, they'll need to vent to the atmosphere in order to dump the air more quickly, and if you've seen the intake on their turbos, ie just a radiused inlet, you know there's no practical way of re-routing vented air there. If you don't believe us, go do a search on the archives at http://www.dsm.org. That has discussions on DSMs from around 1990, by people who eat, sleep and live DSMs. There's so much information there that you'll need months to read through everything.
Okay 1faststealth.
Yes, the tube vents AFTER the mass air. BUT, how did the air get to the CBV in the first place? Through the mass air. Any air you have in the intake at any point after the MAS to the intake manifold have ALL been counted by the MAS, so when you vent pre-counted air back into the intake, you do not need to count it again. Now if you vent this counted air out to atmosphere, the computer is injecting the required amount of fuel for the air that it counted. It doesn't know that a portion has been vented, hence you go rich when the BOV vents. And that's where you get the stumble.
Now, if you think that it is due to the CBV spinning the wheel, why does the stumbling go away when a VPC is installed and a BOV is used? Because now the systems uses a MAP sensor that basically gives a measure of the amount of air right at the intake manifold. So you can blow off half your ingested air, and the VPC will still put in the right amount of fuel.
You see 2G eclipses running better with aftermarket BOVs because the stock 2G CBVs are plastic pieces that do not hold boost very well. I noticed a 2 psi increase when I swapped out the IC pipe and CBV with a hard-pipe and 1G CBV.
Of course it's going to run better.
The reason you get sputtering when you give it a little gas at low RPMS is because the BOVs somtime partially open with a vacumn signal, and lets in unmetered air. Now there's more air then the computer knows, so it goes lean and you get stuttering. ANY component of the intake AFTER the MAS DOES affect the car. For example, you have a leak, you'll run too rich, and you'll stutter.
Point is, our stock MAS system does not work well with BOVs. If you have a MAP system it's a different story. Yes, the fastest cars around use aftermarket BOVs, but what kind of computer system are they running? Stand alone I'm sure. And at the pressures they are running, they'll need to vent to the atmosphere in order to dump the air more quickly, and if you've seen the intake on their turbos, ie just a radiused inlet, you know there's no practical way of re-routing vented air there. If you don't believe us, go do a search on the archives at http://www.dsm.org. That has discussions on DSMs from around 1990, by people who eat, sleep and live DSMs. There's so much information there that you'll need months to read through everything.
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Have you guys seen this BOV?? Below are the links to the pics..
http://www.warmotorsport.com/gofastbitsproduct.html
http://www.warmotorsport.com/gfbproduct/biggfbbov11.jpg
It vents to the intake at low boost and to the atmosphere at high boost.. it's a nice looking piece and it should be very adjustable. It's 150mm tall (about 5 1/2 inches) so it's not a small BOV but neither is the HBV from Turbo XS. Rob from War Motorsports has told me they use this hybrid in their Galants all the time with great success and he's currently working with me to get a mounting kit for the 1g flange.. I know we can't advertise but perhaps the link in my sig will take you to a company that is working to be his US distributor once testing is completed.. But that could be hearsay
http://www.warmotorsport.com/gofastbitsproduct.html
http://www.warmotorsport.com/gfbproduct/biggfbbov11.jpg
It vents to the intake at low boost and to the atmosphere at high boost.. it's a nice looking piece and it should be very adjustable. It's 150mm tall (about 5 1/2 inches) so it's not a small BOV but neither is the HBV from Turbo XS. Rob from War Motorsports has told me they use this hybrid in their Galants all the time with great success and he's currently working with me to get a mounting kit for the 1g flange.. I know we can't advertise but perhaps the link in my sig will take you to a company that is working to be his US distributor once testing is completed.. But that could be hearsay
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Hey Jehu, how did you do that? You took my post and switched your name in for mine. You said exactly what I was going to say!
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