My evo 3 16g setup was pushing too mush boost ( 30-32 psi) for my comfort. I decided to install a mbc to try and set the boost to wastegate pressure, which the previous owner told me was set to 20 psi. The wastegate already had an air fitting with the line running to the j pipe, so I used that j pipe nipple as a boost source for the mbc, and hooked the other line from the mbc up to the wastegate as I'm supposed to. Its an in cabin mbc, and i turned it all the way down. I also installed a NGR bov since i had one in my garage. Now I'm hitting fuel cut at about 5k and its like hitting a wall. Was i supposed to leave the air line in the jpipe from the wastegate and add another air line for the mbc somewhere on the intercooler pipe? or is the issue more than likely an with the bov? Again, it wasnt doing it before i installed these.

If you want to try waste gate just bypass the mbc and see if that fixes it if not undo what ever else you did one thing at a time it's something you did as you said it didn' before.

If you want wastegate pressure then you'll have to hook the J pipe boost source directly to the wastegate. No MBC. Most likely you are experiencing boost creep and there are a few ways to combat this issue like porting the wastegate flapper hole or going external wastegate. Search boost creep on here and read up. I wouldn't continue to hit fuel cut playing with the mbc as it's not going to help.

007jimmy said:

If you want wastegate pressure then you'll have to hook the J pipe boost source directly to the wastegate. No MBC. Most likely you are experiencing boost creep and there are a few ways to combat this issue like porting the wastegate flapper hole or going external wastegate. Search boost creep on here and read up. I wouldn't continue to hit fuel cut playing with the mbc as it's not going to help.

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Thanks for the quick response guys. So what you’re saying is the previous owner already had it set up for wastegate pressure? And that it’s creeping? I have an external wastegate installed. So I’ll disconnect the mbc and reconnect WG to j pipe, then combat the creeping issues correct? Sorry I’m not new to cars just new to forced induction as I’ve been a Honda guy the past 8 years.

Either that or your wastegate arm is stuck. Id make sure by applying regulated air pressure or if you have a vacuum hand pump that will apply pressure using that to see when the wastegate opens.

brian9397gsx said:

Either that or your wastegate arm is stuck. Id make sure by applying regulated air pressure or if you have a vacuum hand pump that will apply pressure using that to see when the wastegate opens.

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Thanks guys, will get back to the thread with updates when I can.

Could you possibly take a picture of the setup?

007jimmy said:

Could you possibly take a picture of the setup?

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This is the only one I have on hand at the moment, this was right when I picked up the car, no mbc or bov installed yet. The air line from the WG is on the j pipe as seen here.

Well thats an external gate so disregard checking for a stuck arm. Id still check for proper operation like i stated

Adjust the NGR bov properly or take the big spring out! I had issues of stalling when it was not adjusted so im guessing yours might be keeping it closed causing an issue with fueling

ec17pse said:

Adjust the NGR bov properly or take the big spring out! I had issues of stalling when it was not adjusted so im guessing yours might be keeping it closed causing an issue with fueling

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Big spring inside the blow off? I tried adjusting it but I may have to take it out. Going to do a boost leak test this weekend I just got a new tester my other one was no good. I removed the boost controller and it’s still cutting fuel around 5k. So after the blt hopefully I’ll have some sort of idea as to what’s going on

Well, if it was "fine" before the MBC and the BOV, and removing the MBC didn't fix it......

One more question your not venting to atmosphere are you? The bov has the hose to the intake correct?

Dsm panda said:

One more question your not venting to atmosphere are you? The bov has the hose to the intake correct?

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Nope, not vented. Everything hooked up as it should be. Only thing not hooked up is the lower nipple on the bov, but everywhere I’ve read said to keep it uncapped.

Mine is uncapped and I had to remove the larger spring for my car maybe try that out.

I hooked up the lower nipple on my Type-s knockoff, i feel that it works much better.

Just an update, BOV was leaking at the flange, fixed and running better.