Boost Leak Question

[ReebisTSI]

I was searching around the forums and really couldnt find a definitive answer so here goes:

The Problem:
Just got my EVO3 GT installed and was looking for 12lbs before i put my 190lph in. It spools right around 3k, and depending on my boost controller setting, spikes to what I assume is what the BC is set to and then immmedialty drops to 8-9 lbs....this leads me to beleive a boost leak


I have performed a boost leak test and have fixed all the ones I have found. I have noticed that there seems to be some pressure leaking from the PCV hose around the spring clip that secures the hose to the valve. Can the PCV be a boost leak spot? Also, I have notiuce that my 1g BOV is leaking a little bit when I pressurize to 15-20 lbs. Could this be my problem, or is it ok since I am recirculating?

Thanks for the help

-bob

 

[FORMONTOYA]

1. Yes
2. 1G BOVs are known to leak a little, but I would like mine to hold to 20psi.

Double check things, usually the biggest leak will be the throttle body shaft seals and BISS screw o-ring. To check the shaft seals, apply your test pressure and rotate the throttle and the pitch will change. Something to check if you haven't or don't know when the last time they were done. Also the BOV gasket is another well known leak spot.

 

[Eastwood95]

have you turned your MBC up or down and then taken the car on another test drive? If so, are you getting the same results everytime? Is the turbo ported? Who ported it? What size wastegate flapper does it have?

 

[Denji]

have you turned your MBC up or down and then taken the car on another test drive? If so, are you getting the same results everytime? Is the turbo ported? Who ported it? What size wastegate flapper does it have?

evo 3 gt comes with specs of an already ported turbo, and a bigger flapper.

 

[TSi Fury]

If your problem persists, there are writeups around DSMTuners on how to properly crush your 1g BOV. I would look at doing that if you can't stop the leaking.

 

[ReebisTSI]

The TB was rebuilt by Hal, and I know he goes thru the whole thing and replaces all the shaft seals and whatnot. And no matter what I set my BC to, it will spike to what I assume is what it is set for and then drop to 8-9 lbs. Next time i run the leak test, I will give the throttle plate a few turns to see if i hear anything. But for now, the only 2 spots are around the PCV and from the BOV. I hopefully will have time this week to run another one, so I will keep you posted. Thanks for the help also guys, I appreciate it

 

[TSi Fury]

When my PCV valve was sticking it would constantly leak. I ended up spraying it with some WD-40 and letting it sit overnight and it started opening and closing properly and quit leaking.

 

[Eastwood95]

could it be a bad boost controller?

 

[ReebisTSI]

Well, after a couple hours with my boost leak tester, I think I've found the problem. I swapped my Dejon 2-stage BC for my buddies home-grown MBC and viola!! It held a steady 12 lbs the whole way. Im thinking that because i dont have a switch wired to the solenoid, the valve will "float" between the two different settings, essentially causing a vacum leak. Im hoping that if i wire the switch in, that this will solve the problem. Does anyone have any input on this or experience with dual-stage BC'ers?