Boost Controller Install - Boost won't turn down

[red240obsession214]

I searched previous posts and couldn't find a solution to the following problem I'm having. I have SR20DET red top in my 89 240sx and about 3 months ago I installed a manual boost controller I purchased off FRsport. I turned the boost all the way down, installed it and then took it for a test drive. It pushed 15 lbs of boost out of the stock T25 and I hear this is bad and it was as it blew the gasket where my turbo meets the manifold, well I fixed the gasket and removed the boost controller. I couldn't figure out why it was pushing so much boost even with it turned all the way down. Well recently I decided to purchase the Turbosmart boost controller thinking there was something wrong with the other one and it did the same thing. Why is it running so much boost even though it's turned all the way down? My connection of vacuum lines from the boost controller is one to the wastegate and the other is tapped into the vacuum line that was originally ran directly to the wastegate. Thanks in advance for any help or suggestions.

[ray666]

are you getting any compression surge or spike? wastegate could be bad. i'd also make sure all you vac lines for your boost are secure.

[red240obsession214]

ray666 thanks for the response. I checked and replaced all vacuum lines and yes I'm getting boost spike. I removed the boost controller and it runs 7psi perfectly fine. Does this matter? Or could the wastegate still be bad even though it runs stock psi fine? Thanks again!

[ray666]

your wastegate should run 7 psi(stock). its quite possible you have a dud controller. when you turn down the boost controller it should come out to 7-8 psi. you're turning it counter clockwise to lower boost right?

[ray666]

the way i have my boost controller setup is from the wastegate and i had to tap into my intercooler pipe just before the turbo. the most common setup is wastgate to the tap on the turbo. my turbo didn't have a tap hence the ic pipe tap.

[red240obsession214]

Yeah, I'm turning it counter clockwise and this is my second manual boost controller and both did the same thing so it isn't the MBC, unless I'm that unlucky. I think I'm going to purchase a nipple to tap into the intercooler piping. Any suggestions where I can purchase one?

[krazydriver]

^ You may have already checked this, but considering it's happened twice, with two different controllers. I would just verify that you're hooking the vac lines up to the proper locations on the MBC.

Something isn't hooked up right if the wastegate is fine by itself, and the MBC is fully turned down and doubles the boost.

[ray666]

frsport has them. i think they call it a quick tap. its only a couple bucks. i put mine on the silicone hose that attaches to the turbo. it should run fine after that. some people use their boost source all the way across the engine by the throttle body, which isn't good. that will cause spiking as well

[red240obsession214]

I agree with you 100% krazydriver and I'm going to hook it up the way ray666 did. Thanks guys and I'll let you know what happens once I get a quick tap and re-install MBC.

[red240obsession214]

I hooked up the tap and it still is running too much boost. I'm convinced there's something wrong with my wastegate.

[ray666]

i believe you should have a nut on your wastegate thats adjustable as well, if thats the style you have.

[red240obsession214]

I'll give it a shot. I'm going to mess with it this weekend. Thanks.

[ray666]

good luck man, it should be an "easy" fix. you would think

[Wretched]

Get a picture of how you have the boost controller vacuum lines set up. Have you tried turning the adjustment the other way?