MBC Question

[kyle248]

Ok I recently bought a 90 gsx and it came with a hallman pro mbc. With the the mbc turned at the lowest setting I pretty much it 10 psi as soon as im pushing the gas however about 3k-4k and up my boost keeps climbing and will go all the way to 20psi if i stay in it or fuel cut will happen. So if any one can help and tell me why i cant stay at a steady boost?

Mods are:
3in turbo back straight pipe
k&n filter
Upper hard pipe
walboro 255 fuel pump
magnacore wires

not really sure if anything else these where on the car when purchesed any ideas or help would be greatly appreciated.

 

[undefined0000]

Welcome to the forums!

We need to know what kind of turbo you have to fully understand the situation, you might just be having boost creep, however with a 3" exhaust, you shouldn't really have too much of an issue with that.

You can find a problem with the MBC by hooking the wastegate directly up to a boost source, so wherever the boost source is for the MBC. If you still hit 20psi, you have creep which tends to happen with restrictive exhaust or a failed wastegate actuator.

 

[kyle248]

Its a stock 14b as far as I can tell and the wastegate acuator is pretty rusted. So you believe the wastegate could be bad?

 

[92AWDHX40]

Possible.

 

[turbolover10]

Like said above, Hook the vacuum port directly up to the wastegate and see if it's holding stock wg pressure. You could also have the mbc installed backwards but that would be unlimited boost.

 

[kyle248]

Is their a guide on how to properly install the mbc cause like I said the car was purchased this way and im not savvy on this car yet Im use to mazdaspeed 3 and my setup look pretty differnt . It will go past 20 but when i see it jump creep past 15psi i let out .

 

[Roberti 2G]

http://www.dsmtuners.com/forums/newbie-forum/3175-mbc-install-merged-10-7-a.html here you go. Its pretty straight foward.

 

[kyle248]

thanks for the help guys