Well, I'm back with proof. Running OEM Atmosphere BOV.

[forcefed86]

Well I was bashed and instantly had 100 people telling me I couldn't do it. Well I did, and it works just fine. Nothing crazy rich on the shifts and no poor idle or driveabilty issues.

Installed LC2 WB02. Went for a test run...

First run with the BOV setup OEM style. At 18lbs WOT I'm seeing around 9.5:1 AFR's. Lifting to shift (BOV active) AFR's jump to mid to high 12's. Then jump back up to 9.5:1.

Swapped in my brass check valve vented to atmosphere. PLugged open hole on intake tube. Same WOT AFR's same boost. At the shift AFR jumps up a bit less at 10.2-10.6, then drops back to mid 9's.

So there it is... do what U will with it. It's sure not washing down any cylinders running at 10:1. That is leaner than the factory map!

The factory AFR targets are as follows.

Also for what it's worth I've done the "dodge garage" MOD to the BOV. If anything this probably slows down the BOV, but thought I'd mention it.

Simple brass check valve installed. I've since painted everything black. But this pic shows the valve assy better.

 

[habitatguy187]

^^^ Tell that to the guys running SD or gm mas'. Most of them will say that they saw an increase in performance just due to the airflow restriction that a mas causes. Which I suppose could over-ride any downsides of venting the bov.

 

[black_gst]

^^^ Tell that to the guys running SD or gm mas'. Most of them will say that they saw an increase in performance just due to the airflow restriction that a mas causes. Which I suppose could over-ride any downsides of venting the bov.

a SD or GM usually gets rid of the need to recir the bov completly

we are talking about a stock MAS correct?

 

[nytescion]

I'd say it does affect performance, the point of a recirculated bypass valve is to keep the turbo spooled, and when you open the throttle again, its decreases the energy needed to spool it. Also since you got to respool the turbo your using more fuel to get that turbo going. In the long run it creates more lag, drop in performance, and increased fuel consumption. For what? Looking cool pulling up to the cruise strips, hang out spot? Each to his own I guess.

If you're really worried about the turbo slowing down or keeping the turbo spooled between shifts then you could always use NLTS.

^^^ Tell that to the guys running SD or gm mas'. Most of them will say that they saw an increase in performance just due to the airflow restriction that a mas causes. Which I suppose could over-ride any downsides of venting the bov.

I would say that yes maybe loosing the air that would normally recirc back into the turbo would decrease performance. Then not having the restriction of a mas before the turbo would help spool the turbo faster. I think these differences would be minimal to the point they'd cancel each other out.

 

[habitatguy187]

I would say that yes maybe loosing the air that would normally recirc back into the turbo would decrease performance. Then not having the restriction of a mas before the turbo would help spool the turbo faster. I think these differences would be minimal to the point they'd cancel each other out.

pboglio did a really good test a long time ago.

http://www.dsmtuners.com/forums/bolt-tech/153744-air-filter-pressure-drop-results.html

 

[snakeyes711]

Nytenscion,You talking about the, National Longitudinal Transition Study? Or speed shifting? its all good I just didn't know what you ment, and thats what came up when I searched.

 

[DIRQUIN]

To the OP. Props on doing it all the way. I like the results you have gotten. Is there a way you can get some pics, or draw a diagram of the valve? You can pm me if you dont want to put it on the thread. I want to use this as a teaching tool to show some good results compaired to not so good. Thanks.

 

[the_mork]

Are you saying there is a performance loss even with maft or sd? I would say not when i was running my 2g mas with bov vta my wideband would go so rich it woudn't register between shifts. Now that I'm running maft and bov vta it runs leans between shifts. As far as the OP posting his car was leaner between shifts with a stock mas and no recirc, I don't know about that either. Sounds like you might have a leak somewhere.

I am absolutely telling you that there is a performance loss even when you are running MAFT or SD. I have had my bov recirculated and un-recirculated while running SD and I can tell you that there is a significant difference in spoolup just after throttle liftoff, if I let my throttle off a little bit as I come up to a tight spot on the track I can feel the car dragging its ass along post blowoff whereas when it was recirculated spoolup was much faster. I am not the only person to report this sort of issue.

I also don't have leaks and even if I did they wouldn't matter, I can literally take off my throttle body and control my engine by putting my hand over the IM inlet. On multiple occasions now I have driven the car without intercooler pipes which does definitely affect performance but the car still ran great. The thing to understand is that unless your leak is so big that the turbo can't overcome it an SD system isn't directly affected by the leak at all (well really there is a minimal difference because of the greater interference created by a higher turbine speed but we can call that close enough to nothing). This is why SD is kind of a wonderful testing bed for what the issues with venting are without worrying about fuel issues and they definitely still exist. Yes MAFT cars are mostly the same but really you just push the air metering back partway. I'm not calling out MAFT setups or really even saying much about the difference here because that is a different discussion and not one that I particularly care about, but I just wanted to clarify that your statement/question at least pertaining to leaks doesn't apply to my situation.

I would say that yes maybe loosing the air that would normally recirc back into the turbo would decrease performance. Then not having the restriction of a mas before the turbo would help spool the turbo faster. I think these differences would be minimal to the point they'd cancel each other out.

This is a matter of scale. On fairly stock setups the MAF is very literally not enough restriction to matter and the spoolup post blowoff probably doesn't matter on a t25 either since it is so incredibly quick. It is once you move to a larger turbo that the differences become apparent and venting caused a greater negative effect on spool after blowoff than the positive effect of moving to a larger exhaust and my turbo isn't even particularly large (evo3 16g). With a slower spooling turbo you start to notice any changes in spoolup and the amount of air that you flow at high boost with a large turbo starts to magnify intake restrictions. Dyno results on a 400hp evo showed a 15hp gain from removing the stock MAF which flows significantly better than the 2g MAF.

If you're really worried about the turbo slowing down or keeping the turbo spooled between shifts then you could always use NLTS.

Some people prefer working transmission to busted piles of gears and oil that need to be swept off the track.

 

[forcefed86]

To the OP. Props on doing it all the way. I like the results you have gotten. Is there a way you can get some pics, or draw a diagram of the valve? You can pm me if you dont want to put it on the thread. I want to use this as a teaching tool to show some good results compaired to not so good. Thanks.

I'm not saying any of this will result in any "good" results. If I had more sensitive test equipment I'm sure I would see that venting decreases performance. I think with my current setup that difference is so minimal it is unnoticeable for street driving and the occasional 1/4 mile blast.

People that say they can "feel" a large difference may not be using a tiny quick spooling turbo. With the spring-loaded check valve type boost control I'm using, my boost comes on very quickly. My compression is slightly higher than normal (resurfaced head .010). And I am running 272 cams.

This may all contribute to my results. I can't say how this will effect a 100% factory original car.

PM sent

 

[inneed4dsm]

wow everyone keeps saying the same stuff so hell might as well give my story... i vented it one time to see what it sounded like cause a friend told me too car ran like crap. It bucked so bad i thought i was going to fly threw the windshield and it would die even if i did push in the clutch when coming to a stop i had to give it gas to let it run.. horrible decision. just get a damn maf-t $200 and a gm maf sensor (i got mine for 15 you might not find on that cheap so im gunna say around 50) and you'll never have to worry about it again..

 

[MidShipCivic]

Once again, mindless chatter. Until you've gone out and done some real world testing. All of that info is speculation.

Aside from possible slower spool times between shifts in an autoxross situation. I don't see any major difference in my numbers. The slight variation in the gtech runs were probably due to slight launch differences. Both runs being within .5mph tells me if there is a performance difference it's pretty insignificant.

But we've already been over all of this.

YOU'RE DREAMING.

Look you're wrong. The system comes circulated it's meant to be circulated the car is slower it waste fuel for what's metered less miles to the gallon, less efficiency= slower car.

EACH TIME you shift you're wasting gas, each time you pull high vac numbers you'll stall who want's to get a check valve for this mess? Honestly if you're looking for noise .. you're a fan boy.

You're looking for a map based car you want noise move over to it fan boy.

 

[tkelly27]

I am absolutely telling you that there is a performance loss even when you are running MAFT or SD. I have had my bov recirculated and un-recirculated while running SD and I can tell you that there is a significant difference in spoolup just after throttle liftoff, if I let my throttle off a little bit as I come up to a tight spot on the track I can feel the car dragging its ass along post blowoff whereas when it was recirculated spoolup was much faster. I am not the only person to report this sort of issue.

I've not experienced this going from recirculated to vented. I've been running SD for a year now. Do you have a log? I remember seeing a test with an evo and it was very small fractions of a second difference. I think it was also still using the stock mass air system.

Feel free to do whatever you want to your car. If you do vent, and you wind up having problems, don't point to this to this thread and say "see, it's ok to vent, whats wrong with my car?!". When I was on the vented mass air setup I would get huge piles of black smoke each shift and foul out the plugs every 1000 miles or so.

 

[the_mork]

I don't have a log and at one point I definitely meant to make one but I haven't gotten around to it and I'm putting the car away for the winter tomorrow so it isn't going to happen at the very least until spring.

Try recirculating again, did you switch to venting right when you switched to SD? If so I can definitely tell you that you wouldn't notice a difference with all the other things going on while you try and get the car tuned. I started by tuning my car for SD with the MAF still on then started venting with that same setup just to see if I liked the sound and because I could. This gave me a fair amount of insight to the differences in performance with changing ONLY whether or not some air got shot back at the turbo inlet. Later I switched my intake tube and had to re-tune a little bit.

 

[nytescion]

I also don't have leaks and even if I did they wouldn't matter, I can literally take off my throttle body and control my engine by putting my hand over the IM inlet. but I just wanted to clarify that your statement/question at least pertaining to leaks doesn't apply to my situation.

I believe i said as far as the OP posting his car was lean during shifts. This part of my post was not directed to you.

This is a matter of scale. On fairly stock setups the MAF is very literally not enough restriction to matter and the spoolup post blowoff probably doesn't matter on a t25 either since it is so incredibly quick. It is once you move to a larger turbo that the differences become apparent and venting caused a greater negative effect on spool after blowoff than the positive effect of moving to a larger exhaust and my turbo isn't even particularly large (evo3 16g). With a slower spooling turbo you start to notice any changes in spoolup and the amount of air that you flow at high boost with a large turbo starts to magnify intake restrictions. Dyno results on a 400hp evo showed a 15hp gain from removing the stock MAF which flows significantly better than the 2g MAF.

I switched from evo mas to 2g mas to my maft. All of which i was using my hx40. Maybe i was over-running the evo and 2g but i noticed nothing but good things such as boost recovery and spoolup from a running start. So i can't agree with you on this.

 

[forcefed86]

wow everyone keeps saying the same stuff so hell might as well give my story... i vented it one time to see what it sounded like cause a friend told me too car ran like crap. It bucked so bad i thought i was going to fly threw the windshield and it would die even if i did push in the clutch when coming to a stop i had to give it gas to let it run.. horrible decision. just get a damn maf-t $200 and a gm maf sensor (i got mine for 15 you might not find on that cheap so im gunna say around 50) and you'll never have to worry about it again..

If your going to post on the thread, at least read it from the start.

Your car bucked because you didn't have a check valve installed as I said to do in the first post.

YOU'RE DREAMING.

Look you're wrong. The system comes circulated it's meant to be circulated the car is slower it waste fuel for what's metered less miles to the gallon, less efficiency= slower car.

EACH TIME you shift you're wasting gas, each time you pull high vac numbers you'll stall who want's to get a check valve for this mess? Honestly if you're looking for noise .. you're a fan boy.

You're looking for a map based car you want noise move over to it fan boy.

See the above statement about reading the whole post before commenting. There are no stall issues. There are no MPG issues. There are no overly rich issues.

Nothing you said even remotely makes sense. You are obviously a half-wit trying to repeat misinformation you've picked up along the way. Much like others on here you just want to post for the sake of posting. Unless you have something worth while to contribute, please don't waste our time.

 

[TRSblader]

I actually find this kind of interesting to say the least, and am glad someone is doing tests and thinking outside the box. I am interested for an update in a few months to see if the setup is still performing well or if you have run into any problems or side effects.

 

[forcefed86]

I actually find this kind of interesting to say the least, and am glad someone is doing tests and thinking outside the box. I am interested for an update in a few months to see if the setup is still performing well or if you have run into any problems or side effects.

Thanks, if it falls apart tomorrow you all will be the first to know. Although I ran this setup on my old 93 talon for roughly 3 years and 20k+ miles without fail.

 

[snakeyes711]

I am absolutely telling you that there is a performance loss even when you are running MAFT or SD. I have had my bov recirculated and un-recirculated while running SD and I can tell you that there is a significant difference in spoolup just after throttle liftoff, if I let my throttle off a little bit as I come up to a tight spot on the track I can feel the car dragging its ass along post blowoff whereas when it was recirculated spoolup was much faster. I am not the only person to report this sort of issue.

It doesn't take a genius to figure this out, when you think about it...Right?

BOV recirculated: The pressurized diverted air is keeping the wheel spinning.

BOV vented: there IS no air to keep the blades spinning. Once the air is gone, you gotta start from the beginning.

Thats not rocket science.....Is it?WTF

Not to mention fouled plugs, after repeatedly being soaked they're bound to be fouled. If you ask me once plugs are fouled they're no good. After many plugs in my bikes I've fouled, I'll tell you cleaning them.....once they're fouled they're gone.

If your going to post on the thread, at least read it from the start.

Your car bucked because you didn't have a check valve installed as I said to do in the first post.



See the above statement about reading the whole post before commenting. There are no stall issues. There are no MPG issues. There are no overly rich issues.

Nothing you said even remotely makes sense. You are obviously a half-wit trying to repeat misinformation you've picked up along the way. Much like others on here you just want to post for the sake of posting. Unless you have something worth while to contribute, please don't waste our time.

Why the check valve, just to make it a one way street? Most people are going to just try to go remove the hose. Or are saying installing a WB, and you can vent your BOV?

Tell me WHY you want to vent the bypass valve, give me three good reasons, because I can give you three good reasons why not to.

 

[MidShipCivic]

If your going to post on the thread, at least read it from the start.

Your car bucked because you didn't have a check valve installed as I said to do in the first post.



See the above statement about reading the whole post before commenting. There are no stall issues. There are no MPG issues. There are no overly rich issues.

Nothing you said even remotely makes sense. You are obviously a half-wit trying to repeat misinformation you've picked up along the way. Much like others on here you just want to post for the sake of posting. Unless you have something worth while to contribute, please don't waste our time.

You are a ricer, there ARE MPG issue's heres what little common sense this requires. AFM meters air & ecu accounts for it by adding guel fuel, air goes missing because of VTA = fuel inefficiently burned = wasted gas.

Slower respooling = slower car

Car stalling yeah I'm not going over that again happens to every AFM based car.

I'm going to repeat this each time until you put it into your brain.


''Hi look at me mod I'm making cool chushhhhhu noises''

You can get this by adding a intake tube it's loud enough already to be heard by other people.

There is also a benefit that is not thought of with a recirculated valve. Recirculated pressure relief is push/pull action as air flows out of the BOV it's being pulled back into the intake tube vs VTA which has a smaller scale effect since atomosphere is low pressure and a charge pipe would be higher pressure .

You tell me what would relieve faster negative pressure from the turbine blades pulling pressurize air or atmosphere?

 

[buryurfear14]

Oh the lengths that people will go to to purposely make their car run worse.

I'm not convinced and your rich shifts are still going to cause you some issues with your fuel trims.

I expect this will make it about a day before it hits the dead end threads section.

Seriously though I just don't get it and I happen to be someone who has a VTA bov but ONLY because my intake doesn't allow it AND I run SD. FWIW as soon as I switched to a MAF delete pipe with no recirculation I immediately noticed a loss of spool after blowing off. If I had a manual I absolutely wouldn't run a VTA, and as it is I wish that I had a recirculation port but I haven't gotten around to finding someone to weld one on for me yet.

Go ahead and say that you don't notice a difference but I and everyone else who has experience with these cars KNOWS that there is a performance loss even in conditions such as a blowthrough setup or SD.

, sound and style is more important than performance, duh.

 

[habitatguy187]

You are a ricer

You sure like to bash don't you? You should stop acting like this is your car and let this guy do what he wants.

Do I agree with it? Not really, as it's not the best thing to do. But if he wants to do it he can and no one can stop him so you should probably quit trying to tell this grown man or any other what he can or can't do.

 

[4g64fiero]

If your not running rich its because the BOV is staying closed and you are actually getting flutter.

End of story.

 

[1993eclipseGS]

A three page thread filled with nothing but people arguing about venting a blow off valve.

Wow.

 

[Rask69]

ok im convinced ! where do i buy the recirculation kit for the ssqv for my stock car?(only has ssqv version 2)

 

[forcefed86]

It doesn't take a genius to figure this out, when you think about it...Right?

BOV recirculated: The pressurized diverted air is keeping the wheel spinning.

BOV vented: there IS no air to keep the blades spinning. Once the air is gone, you gotta start from the beginning.

Thats not rocket science.....Is it?WTF

Not to mention fouled plugs, after repeatedly being soaked they're bound to be fouled. If you ask me once plugs are fouled they're no good. After many plugs in my bikes I've fouled, I'll tell you cleaning them.....once they're fouled they're gone.



Why the check valve, just to make it a one way street? Most people are going to just try to go remove the hose. Or are saying installing a WB, and you can vent your BOV?

Tell me WHY you want to vent the bypass valve, give me three good reasons, because I can give you three good reasons why not to.

I've debunked 2 of your three reasons. As far as blowing hot air that has already been compressed back into the front of the turbo to keep it spooled, well do as you wish. Personally I've found it to be pointless.

I've done road tests that show my specific setup doesn't spool any faster with the BOV recirculating. Or if it does it's such a small amount that it is negligible. I don't autocross my car, so I'm not up and down shifting every 2 seconds. I believe this to be the only circumstance where recirculating would benefit.

And if you'd just read before opening your mouth I've already explained why you need a check valve too. If you really wanted to know an answer you'd read the thread from the start. But you just want to feel good about yourself by calling others stupid. So feel free to stay out of my thread.

You are a ricer, there ARE MPG issue's heres what little common sense this requires. AFM meters air & ecu accounts for it by adding guel fuel, air goes missing because of VTA = fuel inefficiently burned = wasted gas.

Slower respooling = slower car

Car stalling yeah I'm not going over that again happens to every AFM based car.

I'm going to repeat this each time until you put it into your brain.


''Hi look at me mod I'm making cool chushhhhhu noises''

You can get this by adding a intake tube it's loud enough already to be heard by other people.

There is also a benefit that is not thought of with a recirculated valve. Recirculated pressure relief is push/pull action as air flows out of the BOV it's being pulled back into the intake tube vs VTA which has a smaller scale effect since atomosphere is low pressure and a charge pipe would be higher pressure .

You tell me what would relieve faster negative pressure from the turbine blades pulling pressurize air or atmosphere?

Why does your type keep posting. Do you know how ridiculous U sound? I've already tested all these BS claims your making and none of them are true? Sure wish I could delete all posts stating facts that already been proven wrong.

If your not running rich its because the BOV is staying closed and you are actually getting flutter.

End of story.

Once again, why post on something you don't understand. You don't have a clue. It's not that much air people! I'm not running rich because the valve is closed during normal driving. And if you'd read the damn first paragraph of this post you'd see exactly what the mixture is doing under boost.

Your wrong, end of story....

If recirculating is SUCH a MASSIVE improvement over venting. Then why do none of the fastest DSM's recirculate? For that matter why do none of the quickest 1/4 mile cars recirculate? In this type of application a thousanth of a second could be the difference between winning and losing. Don't you think if recirculating BOV air netted any type of gain they would do it?

IMO for my purposes it's all hype.

 

[dsm-onster]

Where exactly does you check valve ends hook up?

I've run the car with out recirculating. Jusmx141 isn't the only one here that's run this cars without recirculating and had all sorts of problems. Ran like shit for me at idle moments after I had it running perfect with a tweek in the tune. I could never get the tune right, because it varied too much. I was chasing my tail. That was becasue the valve opens and "bounces" at idle. All sorts of varying idle hz counts. 33hz is common for idle with most 1g builds and stock. Mine was fluctuating between 33 and 12. Randomly, unpredictably. My a/f gauge would jump to full rich (lm-1 doesn't read below 9:1) between shifts. Black smoke all over the place between shifts. Looked like I was running a diesel with the fuel screw turned up. Stalled at stop signs/lights; anywhere I was over 4K, then let off the gas suddenly. . .

I'm intrigued about how you got this to work. But only becasue it would be nice to know how to not worry about a venting bov and just run a piece of pipe between the turbo and maf. . . I have an easy fix already: recirculating. I'm not into the noise. I'm still working on hiding my intercooler. Besides I've spent enough money getting the air past the maf restriction.


EDIT: I see where you have the brass check valve installed and I assume it is with the flow direction going out of the bypass valve. I've thought about doing this. But I'd rather have my bypass energy directed to the compressor blades to help it spool between shifts I don't run a 14b or something. But like I said, I've spent enough money just trying to get the air past the maf. I'm not into just blowing it out for it to start all over again.