I had a Turbo XS DSBC on my evo and it worked great, 20 PSI no prob. I am going to get my ECU flashed soon so I took the MBC off and added some other mods at the same time. I installed a RMR catback, ss cluch line and K&N Typhoon intake. Now I can’t pass 10 PSI of boost. No matted what gear or RPM if I push the gas it will boost hard to 10 PSI then stops there. My jetta is going faster then my evo now, how sad is that? Anyway I took the whole intake off and put new vac line and clamps so that’s all good. I can’t find any leaks and it still does it. Is my ECU cutting the boost at 10 PSI? Did my stock boost solenoid or wastegate go out? Anyone have any Ideas?

 

Did you reset the ecu after installing/uninstalling the intake? That would be my first thought...I'm no expert, however...good luck, keep us updated! Oh, check all your vac lines again; as silly as it might sound, you might have overlooked something...

 

Did you make sure you reconnected your plug that goes to your MAF sensor? The one right next to the intake? Just a thought.....

 

New vacuum lines and clamps?
Are the restrictors still in place? There are two, one by the solenoid and the other by the turbo down at the T. The turbo one missing will cause low boost. Both missing and I don't know what it does.

 

When you removed the boost controler did you hook the vacuum lines back up to the stock boost control solenoid? Sounds like you are running on spring pressure only without the stock bleeder solenoid in line.

Keith

 

On that note, If I remember correctly if the hoses are switched on the boost solenoid it will have the same effect.

 

Hmm, restrictors you say. I didn’t know there was one by the turbo! Doh. That may be the cause. I am not sure what I did with all the old lines when I installed the MBC about 5 months ago. So I will most likely have to get a new restrictor for the line to the turbo and see if It fixes the problem.

 

read this, there are some things in there that i mentioned, you may want to check it out, i had the same EXACT problem, intalled mbc, took it out and was only running 10 psi.
https://www.evolutionm.net/forums/sh...boost+helifino

 

Mitsu sells the whole deal as a hose kit. It has the tee and restrictors all in place.

 

Ok i ordered the part from mitsu. for $22 it will be in tmro.

 

Sounds like you forgot to plug in the boost solenoid (CEL light if you do though) or you left a vac line to the WG or boost source after turbo unplugged.

 

I put the new vac house from mitsu on and shazam! 19 PSI!! Thnaks for the help guys. I feel like a total lame a$$! What did we learn from this? For future reference removing both restrictors on the vac line will cause the car to only boost to 10 PSI max and that is bad.

 

No need.
There was a big arguement over the restrictor at the turbo in the past and no one believed the guy. I knew cause when I took my hoses off to put on the boost controller I found it in the hose.

 

do you happen to have a link to that thread? i got past the 10psi problem, but now i am having trouble keeping it steady, no matter what setting it will spike to 16 and return to 12ish

 

read this.

https://www.evolutionm.net/forums/sh...d.php?t=115403

and this

https://www.evolutionm.net/forums/sh...hlight=hallman

you need to hook your actuator line back to intake then leave your actuator plug.

Make sure your MBC's back again, otherwise you need to hook your actuator and turbo and intake all back to the actuator with the hoses the stock hoses. They have restrictor hoses in them that is needed for the actuator.

If you can't get a steady boost reading, that means you tapped into the compressor(turbo).

they have a erratic reading for some reason. You could tap into the Bov line, that's more stable.

I think everyone is having problems with taking the MBC off and trying to use the stock actuator setting.

you need to reset your ECU and pump the brakes 15 times in interval before plugging in the battery terminal or ECU harness back.