I have the Forge MBC installed on my evo and been having a weird boost problem. I have a hose going from the MBC to the wastegate and a hose T'd off the bov line to the MBC. There was a little picture diagram I found on the forums that I followed, Can't seem to find it now.

Edit: Found the thread (https://www.evolutionm.net/forums/sh...d.php?t=355302)

But the weird thing is, With the soft spring I run 15psi at 0 clicks and 15psi at 50 clicks. So I put the hard spring in and it now runs at 26psi at 0 clicks, I didn't take it to redline to see how much it tapers down cause I was scared as hell. I didn't turn the clicks up either to do further testing.

My mods include, Buscher intake, EPM o2 dump, DC Sports dp/cat delete, froge RS bov, ets LICP, walbro fuel pump, and esplier exhaust. Car is tuned, But during tuning the LICP kept popping off around 24 psi, Now it's fixed. I'm not sure if during the tune it tapered down to 24psi or what not, I'm worried that even a peak of 26psi would be a bit much for stock block running on pump 93.

I'm about to greese up the ball inside the MBC to see if it helps a bit, it worries me to see 26psi at around 4000rpm

Any insight on why this might happen?

 

You have a stock wastegate? Why are you not using the factory boost source again?

 

take the hard spring out and compress it between your fingers like 50 times (softens it up).

Also run it your turbo outlet instead of your bov.

 

Yep I still have a stock wastegate. I wanted more boost, Stock boost wasn't cutting it for me.

 

Factory boost source ... not level. He's referring to sourcing boost from the LICP instead of the DV actuation line.

 

^ Yeah. Turbo has a nipple and doesn't deal with the vacuum that the dv source has. Much more consistent, i believe.

Try tapping into the Turbo outlet nipple(next to the wastegate) vs using the bov/dv source. Of course bottom of mbc(vertical) = pressure source. Side of mbc (horizontal)=wastegate.

 

I'll give that a shot and see how it goes. Thanks.

 

That hard spring gives me Overboost also. Going to try and soften it up somehow and test again.

 

What type of overboost? Does the stiffer spring help boost taper? I realize it won't eliminate it, but will it remedy even a little?