Trouble hooking up boost gauge

[91Bomb]

CRAPPPP!!! Meant MBC not Bosst gauge


Anyhow I had a plumbing valve hooked up for about a mth or so (no spring + ball) and ran the vacuum line from the nipple of the turbo outlet pipe to one side and connected the other side to line going to WGA. With valve open all the way I was seeing 15 lbs and needed to drop boost a little so I got an ebay ball + spring MBC (nxs). Hooked it up tonight using the same vacuum lines but no matter which way I turn the adjuster I'm seeing way over 15 lbs and even tried reversing the vacuum lines and turning adjuster both ways again and still cannot get anything below 15 lbs. So I removed the ball + spring and left the adjustment all the way backed out as far as it goes and sill way too much boost. What am I doing wrong??

 

[nickk90]

your wastegate spring pressure is 15 pounds so you won't be able to go below that. A MBC will only allow you to rise the boost pressure.

 

[91Bomb]

How does anyone run 14 lbs then?

 

[nickk90]

That is the spring pressure on the wastegate. If you see 15psi its probably just a small boost spike when you get on it then will fall back to 14psi. My car spike to 17psi for a second then falls to 15psi where I have my boost controller set, 2g stock boost is about 12psi. Is their a reason your soo worried about 1psi extra boost even if you fuel system is stock it will handle 15psi.

 

[91Bomb]

Well I was ruunning 15 lbs and seeing some high knock counts and IDC's at wot in upper rpm ranges. It was for .5-2 seconds only two different times on a 15 minute log so I'm not sure if it's something to really worry about or not and when it happened for those brief times as rpms climbed even higher @ wot knock counts, idc's etc returned to nornal so not sure if I'm worrying for nothing.

 

[91Bomb]

My bad


Had a hose leaking air so got everything tight and can now get boost what I want

 

[91Bomb]

*Mods please change to UNRESOLVED + thread title to BOOST CONTROLLER instead of boost gauge.



Well I went back to using a plumbing valve with no ball + spring which didn't work out
even though I could limit boost to less than 15 lbs.

So i looked at my ebay ball + spring MBC and the reason I THINK i couldn't get less than 15 lbs is because it has a vent hole in the bottom of it. Can someone tell me if all MBC's have vent holes So I covered it with mighty putty and also changed the spring to a less stiffer one. Now I can get less than 15 lbs BUT wondering if that vent hole is good to have and if so why??

What I discovered too is using a valve with no ball + spring makes turbo spool slower (makes sense after thinking about it for awhile) so guys with home made mbc's with no ball + spring should seriously not do that