i'm having trouble with my greddy mbc......i need to know which way controls the boost......if i turn the **** all the way to the up position i can blow freely through to the other side...but if i turn the **** to the down position i can still blow through it pretty freely untill it's almost to the end....so my question is the more the wastegate is open the less amount of boost you will have or is it the other way around...i just can't get my kit to boost any higher than 5psi......and the guys at greddy told me about blowing through the mbc to check if it was working properly
and it is.....and i have the direction of flow coming from the turbo into the mbc and out through to the wastegate actuator.....is this correct? also what else could i check to try and remmedy this problem? i have also checked all of my charge pipes and they are all tight...and i don't have any vaccuum leaks....

so can anyone help me out here?

 

The MBC should be restricting the boost signal to the actuator. The more restricted the boost signal is, the slower the w/g will open, and the more boost you'll see.

 

You are correct, if the wastegate flap door were to be shut, you would boost as much as your turbo and setup would allow. If the flap door were open, it would bleed off that excess boost before it hit the turbine wheel, therefore controlling the boost. What psi spring do you have in your actuator?

 

i have the 92-95 greddy kit..which i think comes from greddy set at 5psi...but i tried messing with the mbc earlier and no matter which way i turn the adjustment it still doesn't go past 5 psi...but when i turn it to the boost up direction it definitely spools a lot quicker and it hits 5psi almost insantly....it just seems like if there could be some more adjustment i could boost higher....how about where the actuator arm is connected to the wastegate? i see some threads on the arm where i could adjust at...would this do anything? or can someone post what parts i would need and some instructions on how to make a home depot mbc...thanks

 

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i know some of you guys have to have some suggestions for me to try...