mbc hook up with external wastegate. and turbo question

[msp03rbuld]

Ok ill start off. With how do I hook up the manual boost controller running a external wastegate, also keep in mind there is no nipple on the turbo for the hook up.. Secong, I just installed a hybrid t25/t28 garrett turbo. Is it suppose to be consistantly spinning even at idle or is it normal for it to be at a stand still? Its not tight or anything it spins freely when I spin it with my finger and there's not shaft play what so ever. Any kind of help is greatly appreciated, thanks

 

[yudkib]

MBC goes between your intake mani and EWG... turbo should spin at idle (i would think) but if its not and its still building boost you should be OK....

 

[msp03rbuld]

so i take the feed from the one nipple on the intake mani that goes to the external wastegate and smack dab in the middle? i have a forge mbc which hose goes where? theres a nipple sticking out of the side of the mbc and one sticking out the bottom of the mbc im assuming the bottom is vac and the side feeds to the wastegate

 

[SCMP3]

Not trying to cause any confusion but i was under the impression that the wg was supposed to pull back from the compressor side of the turbo? I know stock Mazda didn't do that but most other cars did. Now Idk much about manual boost controllers and where they go. I understand they go between the wg actuator and im on the stock setup. Just trying to clarify.

 

[yudkib]

ideally, the compressor housing or IC piping has a boost only reference for the wastegate, since theyre not supposed to be exposed to vacuum... something i think contributes to the high rate of WGA failure on these cars.

you are correct about the way it needs to be oriented: the MBC is a ball-and-spring valve, the spring holds the ball closed against the bottom nipple, and the boost pressure forces it open at your desired PSI. the adjustment is very finely threaded to increase or decrease pressure on the spring by making it shorter or longer.

so, bottom side goes to boost reference (intake manifold), side goes to wastegate. and a nice privilege to running the ball and spring valve: now your wastegate won't be exposed to vacuum!

 

[SCMP3]

Ok cool. Thanks for clarifying for me. I plan on building my motor closer to summer time and I'm considering running ewg with whichever turbo decide on. But I havnt fully made up my mind

 

[yudkib]

i would encourage you to run EWG. very strongly.