New boost gauge and MBC issues

Kyser · 03-14-2004, 10:35 AM

Ok, well I finally got a real boost gauge and decided to hook it up. Well we just have it hooked up with no power atm cause we where running short on time, but thats not the point. Anyhow after hooking it up Im getting a constant 21 reading for vacuum which I guess is within a good range(from other posts which generally agree 18 is what you want but 21 isnt bad either) and I boosting around 11ish psi. This number gets up to 12-13 for a brief second when im at WOT, but then it drops back down to like 11. I was like ok seems everything is setup for stock. Now I decided I want too see what my car feels like at 15psi so I cranked the MBC that came with the car down a bit and checked it again. Nothing had happened. Well left it last night figureing something was wrong with it and decided to do some searching today.

After seaching today I found that it is probably hooked up wrong. Of the 2 vacuum lines that are coming off of it one is hooked up correctly to the wastegate actuator(think thats what its called) by the turbo and the other appears to be hooked up to the lower intercooler pipe, when it should be "T'd" into the BOV-intake vacuum line right? Now my question is what is that vacuum fitting or whatever comming off the lower intercooler pipe and if unhook the vacuum line from it and run it to the bov will that do anything.

Sorry I dont have pictures but atm im at work. If needed ill try to snap some when I get home this afternoon and go from there.

~Lyle

gsxtasy91 · 03-14-2004, 10:44 AM

the top hose on the mbc goes teed in with the bov line and the bottom line goes to the wastegate actuator. the lione on the lower ic pipe can be plugged with a cap as can the ones on your air can after you add a mbc!
happy booosting

Kyser · 03-14-2004, 10:55 AM

Sounds good to me, now I just got to wait the hour/hour and a half to get outta work and go pick up some vacuum line cause the piece I need to move is too short.

~Lyle

psychlow · 03-14-2004, 11:20 AM

If it's coming off of the LICP, that's fine. That's actually the line that the car uses to reference boost in stock configuration.

So, it should go like this:

LICP --> In port of MBC ---- Out port of MBC ---> Wastegate

If you blow into the MBC, the 'in' port is the one that is hardest to blow into, as you're blowing against the spring pressure on the ball (no stupid jokes now, guys). If you blow into the 'out' port of the MBC, your breath should exit the vent hole.

If everything is hooked up correctly and you're still only getting 11PSI, check for boost leaks.