No Boost Control

[90GSX182]

I put a mbc on today and it didnt work at all. One side went to the T fitting I made on the line from the bov to the intake mani, and the bottom of the mbc to the wastegate. I tried to ductape the hose end on the outlet from the turbo because it was then exposed. I have the screw all the way down (hopefully that is the min) and the boost shot to 1.2bar (not cool). it probably would have gone higher if I didnt let off the gas. I dont know what went wrong. The only thing I can think of is the MBC is a crappy one the guy had uninstalled when I bought the car.

 

[MrBoxx]

Don't use the BOV line for a manual boost controller.

Please elaborate on what type of boost controller it is: ball and spring or bleed type? Name brand or home-made?

Use the compressor housing nipple for the pressure source in the MBC. The MBC outlet goes to the WG actuator nipple. This is the simplest way of doing it and has no disadvantages.

Taking the pressure source from the j-pipe fitting has many benefits.

1. The main reason why alot of mbc instructions and some tech articles suggests to tap from the BOV line is because it's connected to the intake manifold, the argument is that this is more accurate because it's the same pressure the engine sees. In reality this is a non issue because the boost gauge is tap to the intake manifold no matter where you tap your mbc so there is no advantage in tapping the bov/manifold pressure as previously thought.

2. The proper functioning (opening and closing) of the bov depends greatly on the accuracy of the pressure in the vacuum hose you're thinking of tapping on or off boost so it's best to leave it connected directly to the manifold without any interference.

3. Tapping off the compressor/j-pipe offers the shortest vacuum hose route which greatly reduces the chance of boost spike.

4. In the case of boost leaks, tapping off the compressor/j-pipe will help prevent over boosting the turbo.

5. Hooking up a bleeder type mbc like the TurboXS standard mbc to the bov line will result in a vacuum leak as well as affect the working of the BOV.

-originally posted by oldman

Cap off the stock BCS nipples and leave the electrical plug connected. Block or cap the port on the intake pipe or hose where the BCS hose used to go.

Last of all, make sure you have the MBC installed the right way. Installing it backwards will result in adverse effects.

 

[90GSX182]

Im not sure if is a bleeder or not. ive only had an ebc before. there is a little hole on the side of it that lets out a little bit of air. Its not a name brand one, I think it might be an ebay type mbc, I figured bc it was a freebie it wouldnt hurt. The compressor housing nippe is the one that sits right on top where the intercooler pipe starts?

 

[MrBoxx]

Yes, the compressor nipple is the one actually on the turbo. It sounds like you got a bleeder-type MBC. It's not the best type. You could probably use it for now with no problems, but if you can, upgrade to a Joe P., Hallman, TurboXS, or similar ball-and-spring type of MBC.

 

[90GSX182]

should I have the screw all the way in or out? Im gonna pick a hallman pro up soon, I just wanted to see if this one actually worked

 

[MrBoxx]

In MOST cases, having the screw in all the way produces the minimum boost. unscrewing it will increase boost. Some are different, I think.

 

[oopovertyoo]

i think with the screww all the way in the turbo is not increasing enough force to allow the vaccum line to send a signal to the waste gate to open, as far as i know it's the farther out the less boost tha the farther in the more boost to and extent until the turbo can create enough boost, so try moveing the scre out

Also to plug it up, slice the smaller of the two bov lines and put a T fitting in it, the put a short vaccum line to the bov, ( the side with eh ball bearing in it, or most likly the one below the screw), then connect the other part to the line that runs to the waste gate.
you also need to block off the little vaccum nipple on the intake pipe and block off the little selinoid, but be sure to leave it plugged it!!!!

GOOD LUCK


Shane

 

[2DaTrakNow]

i hoooked mine the same way up that he did, to the BOV/intake manifold line. I have the same MBC probably, its one that looks identical to a turbo XS. Only instead of saying Turbo XS it says "boost controller". Does anybody know what the little T is for though?? its not a normal T, because if you blow in one end, nothing really happens, but if you blow in the other two ends, it will come out of one or the other. I was just confused on what that did and where to mount it.

 

[MrBoxx]

With a bleeder type (such as the TurboXS standard boost controller), the adjusting screw all the way in is minimum boost. Turning counter-clockwise (pulling screw out) increases boost by allowing air to start escaping through the bleed hole(s). This lowers the pressure, which delays the opening of the wastegate actuator.

Don't tap the BOV line for your boost gauge. Leave the BOV line alone. Remember when I said the bleed type MBC's let air out? That's like a boost leak. Do you want a boost leak in the line that controls your BOV, that thing that prevents boost surges from destroying your throttle plate?

 

[90GSX182]

Nah I just ran out and switched it to the compressor outlet, took it for a spin and it still did the same thing. so I ripped it off and ran the hose from the wastegate to the compressor outlet like it was b4. No sense blowing my car up. its a crappy looking mbc anyways. Im ordering a Hallman tomorrow

 

[MrBoxx]

With the direct pressure-to-wastegate actuator setup, do you still have the problem, or is everything back to normal?

 

[90GSX182]

No problem there, it stays at .5 bar like it did before. Im gonna go with the Hallman pro.