MBC Help

[Mock]

So i've search and search, but can't find the answer to my question.

I've got a Turbo XS standard MBC on my 2g GST. I've had it sense i baught the car 25,000 miles ago. Been having some boost issues (i know probably some boost leaks somewhere) but is it possible MBC could break after time? Maybe solenoid could go bad?

 

[fearuponu]

if you have a manual boost controller i couldnt see it going bad.A electric one sure...you can take a manual one apart and clean it.
billy

 

[tallywacker]

So i've search and search, but can't find the answer to my question.

I've got a Turbo XS standard MBC on my 2g GST. I've had it sense i baught the car 25,000 miles ago. Been having some boost issues (i know probably some boost leaks somewhere) but is it possible MBC could break after time? Maybe solenoid could go bad?

Don't blame anything until you do a boost leak test. Also what "boost issues" are you having?

 

[Mock]

Well i took the MBC off again today, just to make sure everything was clean and tight. Also saw bolt on Exhaust housing of my T-25 was about to fall out.Put it back on and went for a ride. Here are what my problems are.

Do have a small needle hole on the vaccum hose to MBC.
After letting car warm up, at idle my vaccum boost is only -16 psi.
At a 3rd gear pull, only boosting 10 psi at most. MBC fully open.
Also noticed my HKS SSQV is alot more quiet.

 

[RiGs2G]

-replace the vaccum line
-vaccum is probably about right, most are supossed to be between -18 and -20. Check for vaccum leaks. Your boost gauge could be slightly inaccurate as well. My autometer one is.
-with the MBC "open" you are only using wastegate pressue. Close (tighten the MBC) for more boost. Stock T-25 cant hold anything iver 12psi or so by redline anyway. Boost gauge could be inaccurate, again.
-I dont know anything about the HKS BOV.
I hope this answers some of your questions.

 

[Mock]

-replace the vaccum line
-vaccum is probably about right, most are supossed to be between -18 and -20. Check for vaccum leaks. Your boost gauge could be slightly inaccurate as well. My autometer one is.
-with the MBC "open" you are only using wastegate pressue. Close (tighten the MBC) for more boost. Stock T-25 cant hold anything iver 12psi or so by redline anyway. Boost gauge could be inaccurate, again.
-I dont know anything about the HKS BOV.
I hope this answers some of your questions.

Helps a lot, thanks man.