Factory BOV vent trick. (Yea, I know...but this one works.)

[forcefed86]

I know there are benefits to leaving the OEM setup. Keeping the turbo spooled between shifts, keeping the mixture correct between shifts. yadda...yadda.....

But, for those that must have the that trick BOV sound on a college budget, this works great for around $10.My car still drives as it did pre BOV venting. No noticeable difference. My WBo2 is arriving soon. I'll check and update this post when it arrives.

Anyway, heres the scoop. Install a brass plumbing 3/4" check valve on the BOV exit plumbing. I used a 3/4" ID rubber hose and kept my factory hose in case I choose to go back. Then use another section of hose with a plug in the end to plug the open end of the turbo intake. I used a 3/4" PVC cap hose clamped and painted black.

This will eliminate any surging at idle due to un-metered air being ingested post MAF. Sounds great and has been working on my cars for years.

Water Source CV-75 3/4" Brass Check Valve - Plumbing & Heating - Septic Tank & Cesspool Equipment - Well Supply Accessories

 

[boostedjay32]

Pictures?
Videos?

 

[95gst16g]

You should take pics of this just because I'm curiuos but I'm sure that it still isnt working how you think it is.....If you want to vent just use a SD or GM maf setup.Thats the right way to do it....

 

[boostedjay32]

yup its never a good thing to work around something... i would just do it the right way ....BUT im still curious on how this looks and works

 

[forcefed86]

Not claiming to have found the holy grail. Just saying it works. I did it a few years back on my 1g talon. And again today on my new 1g. I can't tell a difference, but like stated that doesn't mean there isn't one. I'm not auto crossing or drag racing this one. Just a daily.

Heres a quick pic.

Just to note I'll paint it all black, but I ran out of spray paint. The check valve is pretty heavy duty and has some weight to it. So use good tubing. And make sure you install it the correct way.

You must be logged in to view this image or video.

 

[knochgoon24]

Ok, so instead of running lean from sucking air in through a leaking BOV, he just runs rich during shift from venting already metered air, still leaving the worse of the two problems.

This really isn't a work around.

 

[-TunedDSM-]

Exactly, there's no way around the fact that you are releasing metered air. You may not notice a difference, but there is one.

 

[crimsondragon]

Really?

 

[forcefed86]

I'm not arguing with you all, your right. I already stated this in the first lines of my first post.

I know there are benefits to leaving the OEM setup. Keeping the turbo spooled between shifts, keeping the mixture correct between shifts. yadda...yadda.....

But, for those that must have the that trick BOV sound on a college budget, this works great for around $10.My car still drives as it did pre BOV venting. No noticeable difference. My WBo2 is arriving soon. I'll check and update this post when it arrives.

So your telling me what I already know.

Honestly a BOV noise is pointless in itself, and we all know this. But I can't deny that I like it. Call it childish or what ever U wish but it just sounds "cool" IMO.

All I'm saying is It's not a noticeable difference for mild daily driving. And it fixes the idle issues. I can live with the car being a little rich on the shifts. It doesn't hurt anything. And I'd bet the difference in performance is minimal. I'd be happy to take it to the track and test it with and without this mod. I'm betting it makes little to no difference.

 

[wancsta]

Mods please delete before more newbs see this Not a very productive "tech article"

 

[lacroixdp]

If your car is running properly, you definitely notice the difference. After I put my engine back in, I accidentially threw away my recirculation hose. Being on an extremely tight budget, I decided to rough it temporarily until unemployment started flowing in. After all my vacuum leaks were addressed, it was very noticeable on the highway when running boost, then rapidly releasing the gas pedal, then feathering the gas again - the car would buck. Also on the highway, if I was running boost, then partially released the throttle enough for the BOV to activate, it would buck until I lifted enough off the throttle for the BOV to close. In town shifting, if you didn't pause briefly in between shifts, the car would stagger for a second. What did not happen, however, was stalling issues.

If you have a leak before the throttle body in the intake plumbing, you might be deceived into thinking there is no side effect since you are sucking in unmetered air. Not only is this dangerous since you are running lean, but you are also sucking in dirt and other debris, which will rapidly deteriorate the cylinder walls. If you really can't notice the things I've described above, I'd recommend doing a boost leak test - you may be sucking in unmetered air.

If you really desire that sound, I'd recommend you convert to a blow-thru MAF setup, or convert your car to speed density.

 

[forcefed86]

Mods please delete before more newbs see this Not a very productive "tech article"

You seem pretty narrow minded to me. Fact is it works just like I said it does. Why delete it? I'm sure there are alot of people that would find this useful. And for you to butt into my thread and ask someone else to delete it seems rude. If you don't want to do it that's fine. No one asked you to. So why not just stay out of the thread.

If your car is running properly, you definitely notice the difference. After I put my engine back in, I accidentially threw away my recirculation hose. Being on an extremely tight budget, I decided to rough it temporarily until unemployment started flowing in. After all my vacuum leaks were addressed, it was very noticeable on the highway when running boost, then rapidly releasing the gas pedal, then feathering the gas again - the car would buck. Also on the highway, if I was running boost, then partially released the throttle enough for the BOV to activate, it would buck until I lifted enough off the throttle for the BOV to close. In town shifting, if you didn't pause briefly in between shifts, the car would stagger for a second. What did not happen, however, was stalling issues.

If you have a leak before the throttle body in the intake plumbing, you might be deceived into thinking there is no side effect since you are sucking in unmetered air. Not only is this dangerous since you are running lean, but you are also sucking in dirt and other debris, which will rapidly deteriorate the cylinder walls. If you really can't notice the things I've described above, I'd recommend doing a boost leak test - you may be sucking in unmetered air.

If you really desire that sound, I'd recommend you convert to a blow-thru MAF setup, or convert your car to speed density.

Did you use a check valve installed as I did? My car transitions into and out of boost just fine. I have none of the symptoms you stated? There is no leak before the TB the way I have mine installed.

 

[the_mork]

You can potentially wash out your piston rings by venting.

Just run more boost and your bov will be louder and if you really want then go ahead and move to either ds-map or the evo8 ecu and run SD.

 

[wancsta]

^^Thankyou... Why don't you take a walk outside and take a whiff of your dipstick then you'll know why.

edit: Improperly vented "race" bov's will dump fuel between shifts and get past the rings into your oil.

 

[forcefed86]

You can potentially wash out your piston rings by venting.

Just run more boost and your bov will be louder and if you really want then go ahead and move to either ds-map or the evo8 ecu and run SD.

Do explain this? I don't see how having the BOV modded the way I do hurts anything. Are you saying all the vented race BOV's are prone to washing out piston rings? I find that hard to believe.

 

[lacroixdp]

Did you use a check valve installed as I did? My car transitions into and out of boost just fine. I have none of the symptoms you stated? There is no leak before the TB the way I have mine installed.

No but it was not sucking in air at idle - I don't think it was an issue. I could be wrong though - you never know. However I've been in the game quite a long time and I've never seen someone vent with a pre-turbo MAF with no consequences of some sort. Have you performed a boost leak test to verify that there's no leaks on your intake?

Do explain this? I don't see how having the BOV modded the way I do hurts anything. Are you saying all the vented race BOV's are prone to washing out piston rings? I find that hard to believe.

To put it briefly, you are throwing out air that the computer thinks is going to be consumed by the engine. However, the ECU doesn't know you threw away the air since your MAF is pre-turbo. Therefore, it's still going to inject the same amount of fuel as it would have with all of that air, which will cause your car to run extremely rich for a short time. Fuel in large quantities can wash away the oil film on your cylinder walls that helps the piston rings create a seal in the cylinder. In a worst case scenario this can cause oil contamination, which will wear down your bearings more rapidly.

With all of these negative side effects, you can see why venting to atmosphere with a pre-turbo MAF is not recommended. Your trick doesn't eliminate that problem - it just prevents air from getting sucked in through the BOV.

 

[Rob10_99]

Why does it seem like there's always a big chunk of brass in a dsm engine bay?
The "z BOV syndrome" I see everyday when this local deuche drives by my house, miata with a vortec(yeah....belt driven turbo) and blows off EVERY SINGLE SHIFT.

That's cool right?

 

[misterskeetz]

Okay, somebody else needs to try this before talking like they already tried it on their car. Anybody that has been on dsmtuners long enough knows how to properly vent a bov and even still know the best way to go is recirculated. I will not say this guy is full of crap about his setup because I haven't tried it myself. think of it like a science project. He tried something out and feels he has some good results. So try it before you skip to the results without the actual testing and gathering of your data. The check valve is the variable. Proceed with caution.

 

[forcefed86]

No but it was not sucking in air at idle - I don't think it was an issue. I could be wrong though - you never know. However I've been in the game quite a long time and I've never seen someone vent with a pre-turbo MAF with no consequences of some sort. Have you performed a boost leak test to verify that there's no leaks on your intake?

I've been in the turbo car game for some years as well. And other than a temp. rich mixture during shifts, I don't see why this won't work just fine.

To put it briefly, you are throwing out air that the computer thinks is going to be consumed by the engine. However, the ECU doesn't know you threw away the air since your MAF is pre-turbo. Therefore, it's still going to inject the same amount of fuel as it would have with all of that air, which will cause your car to run extremely rich for a short time. Fuel in large quantities can wash away the oil film on your cylinder walls that helps the piston rings create a seal in the cylinder. In a worst case scenario this can cause oil contamination, which will wear down your bearings more rapidly.

With all of these negative side effects, you can see why venting to atmosphere with a pre-turbo MAF is not recommended.

That does make sense. Although I find it hard to believe it richens the mixture long enough to warrant any concern.

Seems to me you'd need a significant amount of fuel over a decent period of time to wash down the cyl walls enough to harm anything, I have a hard time believing the half second or so it takes to vent the charge pipes would harm anything.

 

[lacroixdp]

Seems to me you'd need a significant amount of fuel over a decent period of time to wash down the cyl walls enough to harm anything, I have a hard time believing the half second or so it takes to vent the charge pipes would harm anything.

You could verify this for yourself easily enough. When you're ready for your next oil change, get an oil analysis done by Blackstone Labs. They will tell you if you have any fuel mixed in with your gas.

 

[gsxtasy]

I've been in the turbo car game for some years as well. And other than a temp. rich mixture during shifts, I don't see why this won't work just fine.

You just stated the main reason to not vent your BOV. I understand that you feel the drawbacks are out weighed with the fact that you can vent your bov. It's your car, do what you wish, but the fact remains that it IS injecting more fuel than it will use. This isn't opinion from members on here, it is a fact. Knowing that, people are still going to do it, and all that we can do is inform you and others that it is, indeed, doing something negative to your engine, and you make your own mind up. I see you've made yours.

 

[joey17]

im going to sell my baby soon anyways so i guess ill try it and report back. as to the op how did you secure the check valve to the bov? pm me your answer ### just incase i loose this thread

 

[Calan]

Okay, somebody else needs to try this before talking like they already tried it on their car

No..they don't.

The theory and real-world examples of why you shouldn't vent a BOV with a stock MAF has been beaten to death for years. It isn't rocket science, and it isn't magic. If you do it, you will see consequences from it in one way or another...period. Whether it's fuel mileage, performance, washed out rings, contaminated oil, or an ECU working it's ass off to balance fuel trims, there ARE negative side affects.

There are 3268327468723684 things you "can" do. That doesn't mean that they should be promoted or recommended. I'm all for experimentation (anyone reading my build blog can vouch for this ). But once an idea has been proven time and time again to be a bad idea, it's time to let it die a peacful death.

If you are dead set on adding a big hardware store check valve into your intake somewhere, research the "D-valve" (named after Dan Culkin). Here is a starter for you. This mod is at least feasible in theory.

 

[forcefed86]

No..they don't.

The theory and real-world examples of why you shouldn't vent a BOV with a stock MAF has been beaten to death for years. It isn't rocket science, and it isn't magic. If you do it, you will see consequences from it in one way or another...period. Whether it's fuel mileage, performance, washed out rings, contaminated oil, or an ECU working it's ass off to balance fuel trims, there ARE negative side affects.

There are 3268327468723684 things you "can" do. That doesn't mean that they should be promoted or recommended.

I'd have to disagree with you. Just because something has been beaten to death doesn't mean there aren't ways around it. If it were left to folks like you we'd still think the earth was flat.

Where is the research and or proof that backs up your claims? Don't make a statement that you can't back up. I haven't said one way or another if this does indeed "wash" the cyls. I highly doubt it, but don't know for sure. The ECU sure won't be over stressed? That statement doesn't even make sense. Fuel mileage is not affected, neither are contamination levels.

So other than a slight rich blip on the fuel maps between shifts, I don't believe there to be any problems with the above setup. I'd even go so far as to say less than a tenth of a second in the 1/4. Which I personally am more than willing to give up for the childish joy of a loud BOV. Esp. on a daily driver.

 

[Calan]

ok...this is past the point of ridiculous now.