Evo 8 MBC issue
 

Hey everyone I just picked up a 2005 EVO 8 about a month ago. When I picked it up it was only boosting 10psi. After searching I realized that it at one point had a boost controller but it had been removed. The stock lines with the restrictor pills had been removed as well. I ordered a new MBC (Hallman pro) and installed it. I then turned the boost up and went for a drive. The problem is the boost didn't turn up it's still at 10psi or wastegate pressure. Do you guys think its my wastegate? All the lines to the MBC are good and there don't seem to be any leaks or loose pipes. Thanks in advance!

Make sure the Inlet on the MBC that has the tiny bleeder hole is on the wastegate side or you'll dump all the air out of it.

you mean like that the line is going to the wastegate or that the hole is facing the wastegate?

You got a pic of how you installed the MBC or even a simple line drawing that you can post up for us to get a visual idea? Which model Hallman is it? Did you install the MBC and route the hoses as per Hallman's install instructions? Does the Hallman come with its own hoses included? Did you source the boost reference from the j-pipe or by T-ing into the hose from the DV to the intake manifold? Is the car equipped with a factory, recirculated diverter valve or does it have an aftetmarket BOV installed?

It's the hallman pro. I followed factory instructions. I'm at work so I can't post a picture or draw a diagram. It did come with its own hoses but I didn't replace the waste gate hose I just used the one that was on it.
Thanks

There is 2 ports on the MBC one going to the Intake manifold or whatever you tapped into for boost source, & the other from the wastegate, the one on the side should have a tiny hole on it where you use a wrench to tighten it "this one is from the wastegate". Make sure the hole fitting is not on the top port going to the boost source.

And when you say just 10psi does it go up higher to like 20ish and drop? or is it hitting 10 and not going further? all these things could help pin point the exact issue

It doesn't go past 10-11psi at all it tops out at wastegate pressure. I have the valve with the hole in it going to the waste gate and the other one on the opposite end of the boost control knob going to a T fitting. The T fitting is going to the intake manifold and the BOV. I turned the knob two full turns after hooking it up.

if im not mistaken, its usually about 1.5 turns on the mbc per psi

what line do you have hooked up to the compressor cover? If i were you i'd disconnect the line from the t and hook it directly up to the compressor cover and see if that helps. So to be sure. The barb on the bottom of the adjustment knob goes to the line on the compressor cover and the other barb connects to the wastegate.

Ok Ill try routing it with just the compressor and wastegate when I get a chance. Also your saying the a turn and a half is only 1.5psi on a MBC? My past care was a T67 3000gt and I had the AEM TRU boost so Im not use to the manual boost controllers.

Finally found time to re-route the mbc. It now boosts over 10psi and is currently at 15psi. However it seems sorta like its cutting out. Maybe fuel cut out? Im confused because its not even at stock boost.

Also make sure you mount the boost controller straight vertically.
You need to have the car tuned at this point. Could be a number of things. It runs higher boost than 15# stock.
19# IIRC.
Check your ignition system, plugs/gap.
Take a look at your MAF, to ensure there is no restrictions also.

U sure ur boost gage is accurate?

Fuel cut Feels like you are hitting a brick wall. Have you done a boost leak test?

boost gauge works fine. The only reason it's at 15 is because I only turned it a few turns. I didn't see any possible boost leak locations but ill have to test it.