Not boosting past 10 psi with aftermarket mbc.

[Okayplayer]

I did a search, and the question i have isn't quite related to what I've found. I did the leak test, fixed the leaks, and I got a brandnew turbosmart mbc, still, no love. Could the stock boost controller have anything to do with it? Maybe an ecu issue?

 

[belize1334]

First, you must eliminate the stock boost controller or you won't boost past ~11 psi. I believe it throws a code if you unplug it so leave it wired in and just tuck it away somewhere.

Second, you have to determine whether you have a check-valve type or bleeder type mbc. The check-valve blocks the pressure signal with a ball-spring. The bleeder type is a controlled boost leak which diminishes the signal by venting pressure. They have to be installed differently as the operate differently.

With a check-valve style you want the source to push against the spring which, when pushed back, allows the pressure to make it's way to the wg actuator. The other two lines go to the source and the wg actuator respectively.

With a bleeder style you want the bleed (leak) to vent either to atmosphere or else to one of the ports on your intake pipe (pre turbo - just like the stock bcs).

 

[Okayplayer]

So should I just cap the lines from the stock boost controller and go from there? Or should I loop them together? /ubbthreads/images/graemlins/dunno.gif

 

[Okayplayer]

Oh, and it is a bleeder type I have it hooked to the bov and a nipple coming off the turbo j pipe.

 

[belize1334]

Disconnect all the lines from the stock BCS. Leave it electrically connected and just tuck it away somewhere.

The bleeder mbc works by venting air from the signal line so that the wg-actuator sees lower_than_actual pressure which causes it to open at a higher boost level. You adjust the boost by adjusting the size of the leak. The mbc should be connected to the j-pipe nipple on one side and the wg-actuator on the other. Then, if the mbc has a third nipple for the bleed, you plumb that back to the nipple on the intake so that the bled air is recirculated.

 

Welcome to the board. How long have you had your car?

 

[Okayplayer]

Thanks for the info, I was also wondering what do I do with the lines that come off the stock boost controller do I cap them? I've had my car since January this year, it's been fun, and quite trying, I got a 16g on it now and shocks/springs from and evo 8. That's all so far