Proper tap in for MBC
 

Hey guys,

On my 94 TSi...I was looking at the MBC the previous owner has in place. It is "T'd" off at the BOV (stock 1G BOV). Can I move the MBC "T" up to the Throttle body and tap into the Red dashed line at the Throttle body?

My reasoning is so the BOV has it's own dedicated line for control and the MBC gets a clear boost/vac signal from the throttle body.

Thanks in advance!

-Kenny

Re: Proper tap in for MBC
 

You could, but I don’t see the benefit.

Re: Proper tap in for MBC
 

Well I guess what my concern is the MBC does not hold vacuum...sort of a free flow but restricts for control of boost. With the MBC tapped on the BOV line it did not seem to open the BOV very well between shifts causing the turbo to stumble.

I hooked it up to the Red dashed line on the Throttle body and without setting the MBC any different it went to 20 PSI! :eek: I cranked down the MBC for my 15 PSI (6000' altitude allows for more boost pressure without incedent) and now I can hear the BOV working much better with less lag between shifts.

I guess another concern of mine for the MBC to the Red dashed line was...what does that go to and would not having much vacuum to it hurt anything?

Re: Proper tap in for MBC
 

For a stock 1G, I always preferred the turbo outlet elbow. The shorter your vacuum lines the better (reduces/eliminates spike plus its less volume for the turbo to fill).

Re: Proper tap in for MBC
 

I agree, I like the turbo outlet elbow.

Re: Proper tap in for MBC
 

It is a stock 1G BOV..but a Big 16G Turbo. I do not see an obvious nipple coming from the compressor housing or that is where I would have tapped in. Is there one under the compressor housing on that turbo? I will be under the car tomorrow replacing the turbo oil return tube bellows. Let me know guys...

Thanks

Re: Proper tap in for MBC
 

The stock turbo outlet ELBOW, not the actual compressor housing but the black elbow that connects to your lower intercooler pipe.