MBC = big problems

[Pro3racer]

Took the car out of storage only changing BOV's and FPR's. Now my boost is completely uncontrolable. My setup is this:

Greddy type S ->line going to intake manifold

Line to manifold T'd and has a line going to my MBC(homemade type, ball and spring)

Line going from bottom of MBC goes to wastegate.

If i hook the BOV vaccum line with the wastegate line(bypassing the MBC), i run a solid 10psi of boost. But as soon as i put my MBC on, I run all boost! My MBC is turned all the way out. Please, i need help on this quick, i have an event next friday, and i'm not running 10psi for it. I have tryed 2 different MBC's as well.

 

[ILLiCliPSE]

I hope you dont have your MBC T'd off of your BOV line. It should have its own line.

 

[elfroggo]

Turn the MBC back into the body a bit and test. I think with my mbc if you had it all the way out the boost would be unlimited also.

 

[Pro3racer]

It must be T'd there, my s16g does not have an outlet, and i'm running a new j-pipe. This thing worked great last summer and all i touched was the BOV and the AFPR, THATS IT!

 

[Pro3racer]

Ok, thank you, i'll go out and check that, and run another boost test as well before it gets dark out. Anymore possibilities please post, i'll be back in 20 min.

 

[romeen]

ILLiCliPSE is right. Use a single designated line for the BOV. Drill and tap you're j-pipe for the boost source to the mbc. Here are some ideas for doing it:

http://www.dsmtuners.com/forums/showthread.php?t=255444

If you're still having problems after doing this let us know.

 

[Pro3racer]

Still having problems, had one small boost leak, but no big deal. I'm not running straight wastegate again, holding a solid 10 psi of pressure. On the Type S, I have my vaccum line going from big nipple(on purple part) to the intake manifold, could I use the smaller nipple for something?

 

[ILLiCliPSE]

Try what romeen said and then come back to us.

 

[Pro3racer]

The problem was with my MBC, first the spring was to stiff and wasn't letting the ball move in the chamber. Then the ball got stuck in the end. Then the spring was to soft and the ball would go too far and sink into the other opening, blocking the air. I finally got the spring right and it works at a nice 17psi.

 

[Dream On]

I would still drill and tap the j-pipe and source it there directly. Having it T's into the BOV line can cause other problems.

 

[oldman]

Keep the MBC connected to the BOV line if you enjoy having a huge boost leak.