MBC... Tee'd to BOV!

[dsm-onster]

Perhaps the pressure in the line itself is stabilized but that doesn't ensure the stabilized pressure equals the pressure in the UICP. There are too many variable involved here, I would suspect the size of the bleeder hole also plays a big role.

You know the "too many variables" plays havoc on research and hypothesis. I'll keep a watchful for the symptoms.

 

[oldman]

That's why they make diffrent size stronger springs and or bigger bov pistons thus my 50mm bov with 12psi spring I think it will hold just fine.

Or you can just not tap the BOV line period.

 

[Slippi84]

I'm gonna run a vac line to my car and let my gf blow into it while on the throttle and tell her to suck when I let off that way I won't T into any line

 

[oldman]

I'm gonna run a vac line to my car and let my gf blow into it while on the throttle and tell her to suck when I let off that way I won't T into any line

Just make sure she swallows when you blow off.

 

[dsm-onster]

At a particular load condition (boost level, engine RPM, and VE) the pressure on the outlet side of the compressor exceeds the capability of the turbos compressor wheel (at it's current speed) to continue to flow air. The turbine cannot perform enough work to cause the compressor to spin against such a pressure. This stalls the positive flow of air through the compressor, and for a moment, the higher pressure on the outlet side actually causes backward flow of air through the compressor housing. When the pressure on the outlet side decreases, the compressor can then make "boost" again...until the process above reoccurs.

Surge is the act of stalling over and over again.

Am I wrong?

 

[dsm-onster]

Just make sure she swallows when you blow off.

too funny!

 

[Slippi84]

At a particular load condition (boost level, engine RPM, and VE) the pressure on the outlet side of the compressor exceeds the capability of the turbos compressor wheel (at it's current speed) to continue to flow air. The turbine cannot perform enough work to cause the compressor to spin against such a pressure. This stalls the positive flow of air through the compressor, and for a moment, the higher pressure on the outlet side actually causes backward flow of air through the compressor housing. When the pressure on the outlet side decreases, the compressor can then make "boost" again...until the process above reoccurs.

Surge is the act of stalling over and over again.

Am I wrong?

I'm no exspert on surge but surge is more when too much air enters the system before the wheel can adapt causing the blades to overspin that's why anti surge ports on covers route air away from the blades.

 

[Slippi84]

Just make sure she swallows when you blow off.

Oh def that is one system that never leakes even under pressure

 

[Maglin]

.... I just typed a hugh article for you all about surge and stall and what not and the stupid back space on my keyboard in firefox is page back. Lost everything. Ok. I'll try to retype it all.

DSM-onster is fairly correct about surge except the turbo doesn't stop spinning. Surge and also known as a compressor stall in the turbine engine world. When the air behind the compressor gets so packed because of to small of a demand the air stops to move in the compressor. The engine never stops spinning but the air inside the compressor stalls and pretty much sits until it can finally go through the engine. This is followed by a very very lound BOOM! The earth shacks and the plane jerks around. If you are watching the engine during a stall you wall physically see a force shock wave emit from the engine. It's very bad for turbine engines and it's also not good for turbos.

In a turbo stall is when the throttle plate closes and a pressure spike in the piping happens. The BOV should open to release the excess pressure but if it's either not working/ hooked up wrong/ or to small it can not release enough air to stop the pressure spike from over taking the turbo. The pressure wave hits the turbo and stops it from spinning. Low amounts of energy to spin the turbine and lots of energy going through the turbo backwards. This is followed by a very loud chirp. It's hard to put what it sounds like into words but if you have heard compressor stall then you know what I'm talking about. It's usually only going to be found on a medium to large frame turbo. Very small turbo's require so little energy to kept spinning it usually isn't a problem but it can still happen.

Surge is just as I mentioned earlier with the turbine engine stall. This happens during operation with the throttle open. Turbo RPM is to low and air demand from the engine is low. The turbo is pumping more air than need be. The air packs up in the piping and can flow backwards through the turbo in spurts. Since the engine is running their is also enough energy on the turbine wheel to kept the turbo spinning. I have no way to explain what surge sounds like. If you know someone with a large turbo chances are they can show you what surge sounds like. I can make any large turbo surge if I want to.

Slippi. I hop your improved BOV source never breaks. That would really blow. Or actually lack their of.

 

[nightspeed87]

Im indecisive on where to tap my boost gauge now...
(Like mentioned earilier in this thread) This lasers boost gauge was tapped to the bov line before I bought it... On my old gst Ive always ran it to the fpr line with no known problems. I know the mbc feed in and boost gauge feed in are too different things, but just to make sure theres no interference with my bov, or fpr Im starting to feel like not wanting to tap into either line. Perhaps I will tap to the p on the tb since I dont use it for anything and its an independent port ...
I have heard tapping into the p on the tb wasnt as accurate according to the information provided by vfaq I believe, but I dont know by what significance. Any input?

 

[super95awd]

Uhhh my MBC is definitely tee'd off my BOV line and will stay that way .

 

[Talesin]

And from the pic of your engine bay, will your BOV stay atmosphere-vented on the stock 2G MAS?

 

[black91awdturbo]

umm the guy is runs 10's on pump I think he is doing ok

 

[Talesin]

And this was the kind of mentality I was trying to point out earlier, when Slippi thought I was calling him a ricer. Just because he's running 10s doesn't mean it's the right way to go about things.

 

[black91awdturbo]

talesin it was a joke man ease up a tad, not every one here is looking for a fight... And for the record I do how ever think 10's on pump very impressive

 

[Talesin]

No worries, tone of voice doesn't translate well into text, and I've had people demanding that I offer 'proof' that reality follows logic and the rules of basic physics. So I'm a little annoyed/pointy to start with.

 

[staticbrainwash]

No worries, tone of voice doesn't translate well into text, and I've had people demanding that I offer 'proof' that reality follows logic and the rules of basic physics. So I'm a little annoyed/pointy to start with.

Exactly how i felt man, exactly. I'm glad to see I'm not the only one in here fighting to see things change for the better though. I just fear this won't change until somehow we totally prove this.

But honestly, we've provided just as much proof as they have. Personal experience.

Maybe if they come back and have pivotal proof that tapping into the bov line DOESN'T cause surge, or any of the other crazy crap that can come from then i'll accept it as a viable option. But really, IMHO, why risk it? Knowing it can even in theory happen.

I apologize if i got anyone offended or pissed, i just don't understand why this concept is so hard to grasp and understand without everyone getting pissy.

 

[Slippi84]

Exactly how i felt man, exactly. I'm glad to see I'm not the only one in here fighting to see things change for the better though. I just fear this won't change until somehow we totally prove this.

But honestly, we've provided just as much proof as they have. Personal experience.

Maybe if they come back and have pivotal proof that tapping into the bov line DOESN'T cause surge, or any of the other crazy crap that can come from then i'll accept it as a viable option. But really, IMHO, why risk it? Knowing it can even in theory happen.

I apologize if i got anyone offended or pissed, i just don't understand why this concept is so hard to grasp and understand without everyone getting pissy.

Anyoen have surge or engine damage from T-ing off the bov come out now (crickets que in now) There's my proof. I don't see why the fact that it hasn't happend TO ANYONE on record yet isn't proof enough that its' just theory. It's like the oswald magic bullet theory. Unless I see someone else get shot with a magic bullet I don't think it happend to begin with in the first place.

 

[super95awd]

Wow, apparently running 10.11's on pump gas is easy nowadays. Strange how no one else has ever done it. Sorry that I havn't updated my pics on Tuners lately. I have better things to do, like build a fast car and not talk about how to do it.

 

[Slippi84]

Now I will have to agree with the other guys on this just because you go fast does not make something the right or wrong way to do things. I believe that T-ing off the bov line is ok because it has yet to damage anyones car not because someone went fast doing it. Going tens on pump gas is bad ass but it does not make you excempt from being wrong. I followed his thread when he was talking about the build trust me the car is no hack job though.

 

[oldman]

Wow, apparently running 10.11's on pump gas is easy nowadays. Strange how no one else has ever done it.

Running low 10's on pump is extremely impressive but it doesn't mean you're right all the time. Case in point, I have had to correct many members in the past on the need for an AFPR with larger pumps because they were told by AMS that it is not needed, AMS certainly has their share of fast cars. Can one get into 10's with FPR overrun? Certainly. Does it make it right? Certainly not! Have you actually gone through the trouble of testing whether your BOV is open under WOT? Who is to say you won't get your 9's if you get off the BOV line.

Sorry that I havn't updated my pics on Tuners lately. I have better things to do, like build a fast car and not talk about how to do it.

Sorry you have that elitist attitude, all of us here have better things to do in life but the purpose of this forum is for more experienced guys to teach, help and share with the newbies, it's not just for showing off.

Anyoen have surge or engine damage from T-ing off the bov come out now (crickets que in now) There's my proof. I don't see why the fact that it hasn't happend TO ANYONE on record yet isn't proof enough that its' just theory. It's like the oswald magic bullet theory. Unless I see someone else get shot with a magic bullet I don't think it happend to begin with in the first place.

Anytime you feel like stopping by, I'll show you the boost leak test with the open BOV. This is just like the venting your crankcase or running an undampered pulley argument, how many people will actually tract back to diluted oil or excessive torsional force with their engine failures? Why is physics alone not enough to convince you that certain ideas are bad ideas, especially when there is absolutely nothing to gain so why take the chance? What exactly is there to gain by tapping the BOV line? Abosolutely nothing, so why the insistance considering all the possible negative side effects?

 

[oldman]

.... I just typed a hugh article for you all about surge and stall and what not and the stupid back space on my keyboard in firefox is page back. Lost everything. Ok. I'll try to retype it all.

DSM-onster is fairly correct about surge except the turbo doesn't stop spinning. Surge and also known as a compressor stall in the turbine engine world. When the air behind the compressor gets so packed because of to small of a demand the air stops to move in the compressor. The engine never stops spinning but the air inside the compressor stalls and pretty much sits until it can finally go through the engine. This is followed by a very very lound BOOM! The earth shacks and the plane jerks around. If you are watching the engine during a stall you wall physically see a force shock wave emit from the engine. It's very bad for turbine engines and it's also not good for turbos.

In a turbo stall is when the throttle plate closes and a pressure spike in the piping happens. The BOV should open to release the excess pressure but if it's either not working/ hooked up wrong/ or to small it can not release enough air to stop the pressure spike from over taking the turbo. The pressure wave hits the turbo and stops it from spinning. Low amounts of energy to spin the turbine and lots of energy going through the turbo backwards. This is followed by a very loud chirp. It's hard to put what it sounds like into words but if you have heard compressor stall then you know what I'm talking about. It's usually only going to be found on a medium to large frame turbo. Very small turbo's require so little energy to kept spinning it usually isn't a problem but it can still happen.

Surge is just as I mentioned earlier with the turbine engine stall. This happens during operation with the throttle open. Turbo RPM is to low and air demand from the engine is low. The turbo is pumping more air than need be. The air packs up in the piping and can flow backwards through the turbo in spurts. Since the engine is running their is also enough energy on the turbine wheel to kept the turbo spinning. I have no way to explain what surge sounds like. If you know someone with a large turbo chances are they can show you what surge sounds like. I can make any large turbo surge if I want to.

Thanks for the clarification, I've always thought they were both compressor surge.

 

[Talesin]

Hey, I had spike when I teed off the BOV line. I since then fixed it. No more spike. Good enough for me.

95, then why come in here if you're not talking about how to do it? And should we assume by the response that you've recirc'd your BOV by this point, or gone to a MAF-T system? Just because it's an old picture doesn't mean anything's different now, after all.


edit- And I always thought surge sounded more like a 'quack' than a chirp. Why my 14b is toast and my 16G is running with a new CBV. Original one was blocked/dead (I suspect with oil), and I didn't know any better at the time, to catch it. :b Thought it was supposed to sound like that.

PS- Head out to CA, see how far pump gas can take you. I'll bring the weenies and marshmellows. Love that 91 craptane!

 

[Slippi84]

Running low 10's on pump is extremely impressive but it doesn't mean you're right all the time. Case in point, I have had to correct many members in the past on the need for an AFPR with larger pumps because they were told by AMS that it is not needed, AMS certainly has their share of fast cars. Can one get into 10's with FPR overrun? Certainly. Does it make it right? Certainly not! Have you actually gone through the trouble of testing whether your BOV is open under WOT? Who is to say you won't get your 9's if you get off the BOV line.


Sorry you have that elitist attitude, all of us here have better things to do in life but the purpose of this forum is for more experienced guys to teach, help and share with the newbies, it's not just for showing off.


Anytime you feel like stopping by, I'll show you the boost leak test with the open BOV. This is just like the venting your crankcase or running an undampered pulley argument, how many people will actually tract back to diluted oil or excessive torsional force with their engine failures? Why is physics alone not enough to convince you that certain ideas are bad ideas, especially when there is absolutely nothing to gain so why take the chance? What exactly is there to gain by tapping the BOV line? Abosolutely nothing, so why the insistance considering all the possible negative side effects?

Switching the source of a mbc is not going to have EVEN CLOSE to impact on things where you will actualy go faster or perform better and there are no ill effects to doing so that can be tracked to realife driving other than your boost test. I'm not even gonna debate you on the boost test I will take your word on it that it does what you say but that is not gonna make me change my location. I T off where I do because it's the most effecient place without possibly creating even more of a problem. Right now my gt14 does not have a compressor nipple. So I would have to drill a whole in to4s pro shroud cover(125 dollar option) hope that the nipple seals right(because if it didn't then you would have slower spool due to a pressurised leak.

You want to work off what if's and theorys try this on for size. Your turbo doesn't have a compressor housing fitting you try and add one. The nipple doesn't seal all the way and the nipple strips the threads and backs out. You now have a open vacume leak and a slow spooling turbo due to a bad boost leak. That's my theory you should change your location NOW!! That's how you guys are coming across. Everything I said is possible and logical but does that make you want to run out to your car and change it back?

 

[Talesin]

You could always drill out a larger hole, or re-tap for larger threads. And JBWeld is your friend, and should be used even if the fitting screws in tight, and doesn't leak initially. The compressor housing is a good place, but the outlet elbow will also do... I know very few aftermarket j-pipes have vacuum nipples[/sarcasm], but if you can't drill a hole and fit (essentially) a bolt into it, you might want to reconsider automotive modification for performance as a goal.