Wierd MCB install / setup

[madman]

So I had some engine work done on the car ( valve job ) and had the mechanic install my new turbo, manifold, etc.... and I'm looking at how he hooked up the MBC and I've never seen it done this way.

The first pic is from Defiant's tech article ( hope you don't mind me using it ) which shows how a MBC is normally installed.

The second pic is how my mechanic is installing it. He says that this will actually keep a larger turbo ( mine is a 50 trim ) from creeping because of the vaccum leak from the side nipple being left open / uncapped.

Has anyone of seen this or heard of this?

I don't get the car back till Monday and then I drive out of town. I should be able to adjust the boost pressure and see if this actually works.

 

[Justins99GSX]

This is not the proper way of hooking up a MBC, Hook it up according to Defiant's picture and you will have no probs controling boost..... I have seen wierder things, for example some guy running his car without the main fan and no thermostat... :WTF:

happy boostin
Justin

 

[madman]

This guy has worked on dozens of DSMs and who know how many other performance cars.

I trust this guy but I'm kind of skeptical about this at the same time.

Who knows, maybe this will be a new way of controling boost creep.

 

[robs90tsi]

Ive never ever even heard of someone doing that before, nor suggesting it, I dont see how the MBC can function like that. I use the wastegate and J-pipe, and wouldnt use any other method of install for my MBC.


EDIT: Oh wow, I didnt even realize that he left the upper nipple alone, that does you no good whatsoever, it will not work like that at all.

 

[hewhoisknot]

The way your mechanic hooked it up does even allow the MBC to perform it's function. If you know the mechanics of an MBC you can clearly see this is as good as not having an MBC.

 

[mavisky]

This guy has worked on dozens of DSMs and who know how many other performance cars.

I trust this guy but I'm kind of skeptical about this at the same time.

Who knows, maybe this will be a new way of controling boost creep.

Don't trust him with this kind of thing anymore. He just bypassed your boost controller. You won't have any boost control whatsoever like that. It'll run around on whatever boost the wastegate actuator opens at, probably 10psi or so.

 

[madman]

Don't trust him with this kind of thing anymore. He just bypassed your boost controller. You won't have any boost control whatsoever like that. It'll run around on whatever boost the wastegate actuator opens at, probably 10psi or so.

That's kind of what I thought. It would be just like there was no MBC at all.

I thought maybe he was doing it just to let the turbo break in, to make sure I don't over boost it. You think he would just state that though, instead of comming up with something like "if keeps it from creeping".

I'm still curious if it some how works. I plan on leaving it like that and take him on a test drive when I pick it up incase there is any issues and see if we are able to adjust the boost at all.

I will let you all know how it works.

 

[andytalon]

Did you not just relize by what they all said, its bypassing your mbc so with that its isn't doing jack at all. Do you understand how a Mbc works? If not learn and then comback with your mechanics way and tell us it is right. It its defenitly not right, and I would put it back to normal. If you want to break in your turbo, or whatever run low boost. Just set it on the Mbc, thats what the knob on the top of it is. Come on don't go trusting this guy, that is one of the stupidest things i've ever seen. I bet the damn guy didn't even know what it was so he bypassed it. Just hook it up right and do it right so you don't cause any problems please! good luck sorry for being harsh good luck bro

 

[trd-2-dsm]

i'm looking at the picture at the beginning of the thread and i have a question. i was always told that it was best to give each device it's own vacuum or place to recieve vacuum from. ie the boost gauge has it's own vaccuum, the bov has it's own vacuum, and the mbc has it's own vacuum. correct me if i'm wrong though please. it's just a question (not trying to thread jack)

 

[madman]

i'm looking at the picture at the beginning of the thread and i have a question. i was always told that it was best to give each device it's own vacuum or place to recieve vacuum from. ie the boost gauge has it's own vaccuum, the bov has it's own vacuum, and the mbc has it's own vacuum. correct me if i'm wrong though please. it's just a question (not trying to thread jack)

My boost gauge t's off of the fuel pressure regulator line from the intake manifold, which as far as I have seen, is a common practice. It was in the instructions from Greddy for the EBC ( profec II ).

How would you come up with their own source? Unless you make new fittings off of the manifold or inatke pipes it seems like they have to tap into an existing line.

 

[madman]

Did you not just relize by what they all said, its bypassing your mbc so with that its isn't doing jack at all. Do you understand how a Mbc works? If not learn and then comback with your mechanics way and tell us it is right. It its defenitly not right, and I would put it back to normal. If you want to break in your turbo, or whatever run low boost. Just set it on the Mbc, thats what the knob on the top of it is. Come on don't go trusting this guy, that is one of the stupidest things i've ever seen. I bet the damn guy didn't even know what it was so he bypassed it. Just hook it up right and do it right so you don't cause any problems please! good luck sorry for being harsh good luck bro

I understand what everyone is saying and I tend to agree with them and yes I know how a MBC works, BUT.....

I'm just trying to keep an open mind and if it don't work then I don't see in any harm of trying. Worst case I will only be limited on the boost.

The more I'm thinking about it......... the open fitting on the MBC creates a vaccum leak right, so you would think that you would not even be able to hold boost as stated above (maybe 10psi), but that leak is being regulated by the MBC. Wouldn't the air try to escape through the least resistance first, which would be the air leak, till it reaches the pressure the MBC is set too and then actuate the wastegate.........Just a thought

 

[madman]

Everyone keeps asking me if I know how a MBC works so I looked it up just to refresh myslef and make everyone happy. This is just the first web sites I came across.

I found this on this website:

http://www.hackaday.com/entry/1234000267047266/

"A manual boost controller is placed in the path of the waste-gate’s sensor. The controller bleeds off some of the pressure in the line so that the pressure measured at the waste gate is lower than actual. This tricks the waste gate into staying closed longer than usual so a higher level of boost is reached."

This kind of goes along with my last post of how this might work.

 

[mavisky]

i'm looking at the picture at the beginning of the thread and i have a question. i was always told that it was best to give each device it's own vacuum or place to recieve vacuum from. ie the boost gauge has it's own vaccuum, the bov has it's own vacuum, and the mbc has it's own vacuum. correct me if i'm wrong though please. it's just a question (not trying to thread jack)

It is best, but since a stock dsm only has a couple of vacuum/boost ports it makes it hard to do. From the factory they use the small nipple on the turbo outlet elbow which isn't a good indicator of true engine boost as it's measuring it at the very beginning of the system.

 

[jking29]

With your mbc hooked up like this, you are just in effect creating a boost leak. I would have to guess that it would bleed off enough to cause a great big spike when your turbo spools up.

 

[VelocitàPaola]

Are you sure you have a ball/spring type boost controller? It looks as though your mechanic was trying to hook up a bleeder type boost controller. Both are valid designs, but they can not be hooked up in interchangeable configurations.

"A manual boost controller is placed in the path of the waste-gate’s sensor. The controller bleeds off some of the pressure in the line so that the pressure measured at the waste gate is lower than actual. This tricks the waste gate into staying closed longer than usual so a higher level of boost is reached."

This is how a bleeder type BC works; and yes, it does work! I think you, and everyone else who's posted so far, are assuming that you have a ball/spring type BC - which works in a different way. The ball/springs restrict boost to the wastegate actuator, they don't bleed it off.

 

[madman]

Are you sure you have a ball/spring type boost controller? It looks as though your mechanic was trying to hook up a bleeder type boost controller. Both are valid designs, but they can not be hooked up in interchangeable configurations.



This is how a bleeder type BC works; and yes, it does work! I think you, and everyone else who's posted so far, are assuming that you have a ball/spring type BC - which works in a different way. The ball/springs restrict boost to the wastegate actuator, they don't bleed it off.

I have a Joe P MBC which is a ball and spring.

I'll will bring this up to the mechanic and see if he thought it was a bleeder style.

Thanks

 

[madman]

Ok, soooo everyone was right, the way the MBC was hooked up was completly bypassing it.

No matter how much I adjusted it, I could only get 10psi.

For the people who were right, don't let it go to your head, It was probably your first time

Just kiddin