What's Needed with Blow Off valve i modified?

[RedEyeBanDiT]

DDG- Talon BOV mod for HIGH BOOST

i did this mod here with my stock blowoff valve. Do i need anything like a maf translator or anything? or will it work fine? I have 90 1g with 3inch exhaust and intake.

Thanks

 

[turboking15]

no you dont need a translator you just need to make sure that you hook up the factory recirc hose so the car runs right.

 

[RedEyeBanDiT]

thanks

 

[RedEyeBanDiT]

I did this mod with hte new port connected to a t fitting between my wastegate and j pipe. The bov sucks air in while idling and this causes it to idle erratically,. and it runs like shit. With the same setup with the recirculation hose conected the cars runs fine and is boosting at 14-15 psi. What will happen if i take off the vacuum line to the new port and run it with and then without the recirculation hose????????????????????????

 

[dsm-onster]

Your engine will die between shifts in town driving. You'll run extremely rich at those points and your gas mileage will suffer. Unless you release the throttle completely every time you shift (this will activate "injector cutoff"). The latter exercise I mentioned is a pain in the ass. So just recirculate and enjoy not having to buy a bov upgrade if you want to run 30 psi someday.

 

[kenamond]

I did this mod with hte new port connected to a t fitting between my wastegate and j pipe. The bov sucks air in while idling and this causes it to idle erratically,. and it runs like shit. With the same setup with the recirculation hose conected the cars runs fine and is boosting at 14-15 psi. What will happen if i take off the vacuum line to the new port and run it with and then without the recirculation hose????????????????????????

Your post is confusing me. After the BOV mod, there are four points on the BOV that "connect" to some pressure/vaccuum source:

- Intercooler pipe recirc valve: This is the valve you see from the bottom of the football-shaped flange on the BOV that will be hidden when you bolt the BOV to your intercooler pipe.
- Vaccuum source: This is the stock nipple on the BOV that connects to your intake manifold.
- Recirculation pipe: This is the big tube on the side that gets connected back to your intake pipe.
- Extra nipple: This is what you added by doing the BOV mod.

No matter what you do, the 1st three have to be connected in the stock configuration. The only variable in the setup should be what you do with the extra nipple.

If you leave the extra nipple open, the BOV will hold much more boost pressure without leaking than an unmodified 1g BOV, but it won't "quick release" or open as quickly as the stock 1g BOV.

If you connect a boost source to the nipple, you add in the quick release, but the BOV will now go back to only holding 17psi boost without leaking.

There are possible setups "in between" these two options where you apply *part* of the boost pressure to the extra nipple and get a bit of quick release along with being able to hold a bit more boost, and you can get anywhere in between by hiding different amounts of boost (hide none and you get quick release but leak at 17psi, hide all and you get no quick release and much higher boost without leaking).

Now this is independent of your boost controller. If your boost controller is limiting boost to 15psi, it doesn't matter what you do to the 1g BOV; you'll get 15psi boost. If you have supporting mods to run more than 17psi boost or whatever your particular BOV happens to leak at, you'll have problems getting past this boost level unless you mod the BOV (leave the extra nipple disconnected from everything or only "show" it part of the boost pressure).

So from your post, it sounds like you tried running it with the BOV recirculation tube disconnected from the intake pipe. If that's what you meant, you can't do this without a blow-through setup. Also, it sounded like you had the extra nipple connected to the boost source (T-ed into the j-pipe-to-WGA vaccuum line). If that's the case, then you are keeping quick-release mode at the cost of being able to keep the BOV from leaking at high boost. If you meant something else, I'm not understanding it and would appreciate some clarification.

 

[RedEyeBanDiT]

Your post is confusing me. After the BOV mod, there are four points on the BOV that "connect" to some pressure/vaccuum source:

- Intercooler pipe recirc valve: This is the valve you see from the bottom of the football-shaped flange on the BOV that will be hidden when you bolt the BOV to your intercooler pipe.
- Vaccuum source: This is the stock nipple on the BOV that connects to your intake manifold.
- Recirculation pipe: This is the big tube on the side that gets connected back to your intake pipe.
- Extra nipple: This is what you added by doing the BOV mod.

No matter what you do, the 1st three have to be connected in the stock configuration. The only variable in the setup should be what you do with the extra nipple.

If you leave the extra nipple open, the BOV will hold much more boost pressure without leaking than an unmodified 1g BOV, but it won't "quick release" or open as quickly as the stock 1g BOV.

If you connect a boost source to the nipple, you add in the quick release, but the BOV will now go back to only holding 17psi boost without leaking.

There are possible setups "in between" these two options where you apply *part* of the boost pressure to the extra nipple and get a bit of quick release along with being able to hold a bit more boost, and you can get anywhere in between by hiding different amounts of boost (hide none and you get quick release but leak at 17psi, hide all and you get no quick release and much higher boost without leaking).

Now this is independent of your boost controller. If your boost controller is limiting boost to 15psi, it doesn't matter what you do to the 1g BOV; you'll get 15psi boost. If you have supporting mods to run more than 17psi boost or whatever your particular BOV happens to leak at, you'll have problems getting past this boost level unless you mod the BOV (leave the extra nipple disconnected from everything or only "show" it part of the boost pressure).

So from your post, it sounds like you tried running it with the BOV recirculation tube disconnected from the intake pipe. If that's what you meant, you can't do this without a blow-through setup. Also, it sounded like you had the extra nipple connected to the boost source (T-ed into the j-pipe-to-WGA vaccuum line). If that's the case, then you are keeping quick-release mode at the cost of being able to keep the BOV from leaking at high boost. If you meant something else, I'm not understanding it and would appreciate some clarification.

YUP thats exactly what I did originally, new nipple t'd in vacuum ALONG with the BOV recirculation tube disconnected that made it run crappy. Then I connected the BOV recirculation tube and it runs better. My bcs is connected to my intake and the other nipple on my bcs is broken off with nothing on it. With this setup sometimes I'm running 15lbs of boost and sometimes im running 13-14 lbs.

Before I f'd with my BOV and fixed my exhuast leak, I was consistently running 15lbs and would spike to 20 lbs. ( IKno this isnt good).

Now my question is should I leave that extra nipple connected or disconnected to a vacuum source?? I cant hear any difference in sound with this mod that I just did with the recirculation tube connected. What was the purpose if the recirculation tube still recirculates in the intake?

Thanks for your help sorry for confusing

 

[tkelly27]

The purpose is to keep the lower portion of the diaphragm from pushing the valve open at higher boost levels. Keep it recirculated.

 

[RedEyeBanDiT]

Sooooooooo, know i should put ANOTHER T fitting in between the wastegate and the j pipe and add a boost controller????

Before I try it, What will happen if I unplug that new nipple I added and run no vacuum to it ?????? more boost less boost suck air ?????????

 

[dsm-onster]

If you do not connect the new vacuum port you created to any vacuum/boost source, the the valve will hold tighter at very high boost. above 20 psi. It allows you to run very high boost without having the valve crack open from it's seat slightly and consequently overspinning your turbo. Just what Mack already said. But it will also be sluggish at opening when it should open, when you let off throttle. IT does open when you close your throttleplate, but it just does it a bit slower. This slow reaction to your throttle control *can* cause compressor surge and *could* prematurely wear out your turbo bearings. Although, I've not actually seen or heard of a turbo failure that difinitively was caused by such.

If you connect the new vacuum port you created to a pre-throttleplate port (T the boost control solenoid line), then it will function as if the mod had not been done. You'll have the quick release action of the valve and you'll be able to run 15-18 psi before the pressure begins to crack open the valve.

If you connect the new vacuum port you created to a post-throttleplate port (vacuum line from the intake manifold), then you're valve will likely never open even when the throttle is closed because your sending vacuum to the underside of the diaphragm HELPING the spring keep the valve closed. So it's possible that it will not function at all like if you had no bypass valve installed. I actually have seen severe turbo failure from not running a bypass/blow-off valve.

You don't need to use this mod right now. You're running under 18 psi. So T right at the j-pipe nipple and run a line to your new port.



To answer your question on why your boost is now lower. . .

If you're bcs is only connected to the intake (broken nipple), then how can it control the wastegate actuator and consequently boost? You have a T in the line from the j-pipe nipple to the wastegate actuator from where that broken nipple is to be fed. You're now usign that for the bypass valve modification. The wastegate actuator is seeing actual boost and will have some fluctuation (as you described) as it opens based on boost AND the pressure exerted on the wastegate from the exhaust gases. The BCS helps a little to stablize the boost and to raise the boost above wastegate actuator response pressure. You should fix that or get another BCS. I suggest just getting a manual boost controller and attaching it down the j-pipe/wastegate line away from the T you need for the new port on the bypass valve.




So to re-iterate. . .

To have the bypass valve run as if you had never modified it, you should have 2 Ts in the line from the j-pipe to the wastegate actuator. The T close to the j-pipe should run to the new vacuum/boost port you created on the valve. The T close to the wastegate actuator should run to your stock boost control solenoid.

. . . So now I basically have just said what Mack said.

 

[JusMX141]

If you do not connect the new vacuum port you created to any vacuum/boost source, the the valve will hold tighter at very high boost. above 20 psi. It allows you to run very high boost without having the valve crack open from it's seat slightly and consequently overspinning your turbo.

I was always a bit confused by the stock BOV mod. I thought that by leaving the quick release hose disconnected that it would actually hold LESS boost because it doesn't have that extra bit of pressure coming from the compressor housing that is helping to hold the diaphragm down.

 

[dsm-onster]

I was always a bit confused by the stock BOV mod. I thought that by leaving the quick release hose disconnected that it would actually hold LESS boost because it doesn't have that extra bit of pressure coming from the compressor housing that is helping to hold the diaphragm down.

The hole that you plug in the dodge garage mod is fed from the same source as the new port you create, if you so choose. It is otherwise left open to the atmosphere and the chamber it feeds sees ambient pressure. The chamber which is fed by this new second port created OR from the hole you plug that's inside the bypass valve flange expands with boost and contracts with vacuum (of course ). The spring pressure is against this second chamber; so boost minimizes the pressure much like a wastegate actuator.

 

[JusMX141]

I see. I always thought the hole you plugged on the bottom led to the boost reference chamber and aided in holding the BOV shut; not the quick-release chamber.

 

[RedEyeBanDiT]

I was always a bit confused by the stock BOV mod. I thought that by leaving the quick release hose disconnected that it would actually hold LESS boost because it doesn't have that extra bit of pressure coming from the compressor housing that is helping to hold the diaphragm down.

NOPE now your confused about it. The recirculation HOSE is always CONNNECTED!!!! Thats why i dont understand this mod, cuase you leave it on so it dumps back into the intake....whats the purpose? haha

 

[RedEyeBanDiT]

So if I leave the new vacuum port disconnected how much boost do you guys think I'll be running??????
seein one bcs nipple is broke, the only on there is the one that goes to intake.

 

[JusMX141]

NOPE now your confused about it. The recirculation HOSE is always CONNNECTED!!!!

Uh, I knew that. I'd never run my BOV to vent unless I had a GM MAS and Translator.

 

[kenamond]

Just to clarify some things...

If you look at the picture dsm-monster posted, there are three "chambers" in the BOV that are all separated from each other:
- First, there's the chamber where the spring is. This has a vaccuum port on it that goes to the intake manifold, and the bottom of this chamber *is* the diaphragm.
- Next, there is a chamber at the bottom of the picture. This opens up to the recirculation tube. If you take the BOV off or pull the recirc tube off and look inside, you'll see this chamber. The bottom of this chamber is the valve that separates the UICP from this chamber.
- Finally, there is a chamber between these previous two chambers. The top of this chamber is the diaphragm. In a stock 1g BOV, there is a small port that runs from this chamber down to a small hole on the bottom of the BOV that would normally be open to the intercooler pipe. In the mod, you're redirecting this small port to the intercooler pipe to an external nipple so that you can feed it "something special" or have control over what that port sees in terms of pressure. You can see it in the image with an arrow saying "Hole that is is to be plugged".

So, the diaphragm has the first chamber above it and the 3rd chamber below it. When the IM sees vaccuum, it pulls up on the diaphragm. In the stock configuration, the boost pressure in the intercooler pipe also pressurizes the 3rd chamber below the diaphragm. This helps "crack the seal" of the valve which gives you a "quick release" on the BOV when you shift or otherwise let off the gas pedal and close the throttle plate. Of course, there is a shaft that connects the diaphragm to the valve, so when the diaphragm is moved up, the valve goes with it, and the intercooler pipe airflow flows through the 2nd chamber into the intake pipe (recirculates).

The thing is, in the stock setup, the boost pressure in the 3rd chamber is acting on the diaphragm and trying to push it up. The intake manifold is going to have a bit lower pressure due to losses between the BOV and the IM. Furthermore, the small vaccuum line between the IM and BOV causes a big pressure drop, too. So the 1st chamber is typically at a lower pressure than the 3rd chamber when you're boosting. When you boost past 17psi, the pressure difference between the 1st and 3rd chamber (which are on either side of the diaphragm) is enough to crack the valve loose and start leaking some boost back into the intake pipe.

So the mod lets you control the pressure in the 3rd chamber. If you connect a boost source to it, you get the stock behavior. If you leave it open to atmosphere, then the 3rd chamber isn't pushing up on the diaphragm at all, but the boost pressure in the IM is still feeding the 1st chamber and holding the diaphragm (and valve) down (and shut). The higher the boost, the harder the valve is held shut.

But what you *can* do is put a bleeder or ball-spring MBC on that extra nipple's vaccuum line and adjust it so that you boost that 3rd chamber *some*.

If you dial down the boost value on that extra MBC, it will let more of the boost signal get to the 3rd chamber (that's just how MBCs work...lower boost settings hide less boost, while raising boost settings hide more boost). The lower the boost setting, the closer you get to stock 1g BOV behavior.

If you dial up the boost value on that extra MBC, it will let less boost signal get to the 3rd chamber. The higher the boost setting, the more boost the 1g BOV can hold without leaking, but at the cost of less "quick release".

Enough of the BOV stuff...now onto what you should do in the meantime for a MBC.

As dsm-monster pointed out, you should have 2 T fittings on the j-pipe-to-WGA vaccuum line. The first (closer to j-pipe) goes to the extra BOV nipple...that gives you stock 1g BOV behavior. The 2nd T goes to the broken BCS nipple. For now, just cap that vaccuum line. This will give you around 9-10psi boost. It might be a bit low for your taste, but until you get a new BCS or MBC, you're playing with fire. This will be safe, and you won't damage the motor by running lean or knocking. And if the slightly lower power bugs you, that will just make you replace the BCS that much sooner. And while you're at it, maybe you can get two of them and then be able to adjust the BOV with it so that you can hold the boost without leaking (but not hold much higher than that) but also get the quick release feature.

 

[dsm-onster]

Who'd ever thought a simple spring-loaded chambered device would be so complicated . . .

 

[kenamond]

Who'd ever thought a simple spring-loaded chambered device would be so complicated . . .

Have you read the thread donmajicjuan and I were yapping in all about how a ball-spring MBC works? Now *that* is a lot more complicated than it would seem for such a basic-looking contraption!

 

[RedEyeBanDiT]

thanks guys !!!!