Just wondering, since my quest to find the Neverending Boost Leak keeps coming back to the BOV. It's as if it pops open and sticks when enough boost is applied for a certain duration. The more I troubleshoot, the less peak boost I'm able to run before my big leak occurs. With the BOV return line capped during my pressure test, I got up to 1.6bar with no leaks, but as soon as I drive with the BOV reconnected to the intake, I experience the big leak again at high boost. This is not a 2-3psi leak; it is as if someone opened up a big hole and let ALL the pressure out, because my boost gauge drops almost to 0 if I keep the throttle open and continue to try and accelerate.

Anyway, back to the question, I'm just wondering who all has run 21psi with an MBC while still using the stock BOV and if anyone has experienced it failing and/or the spring losing tension/strength. My MR DV is on the way, but it's been 3 weeks since I ordered it...

 

Although its not very common, the stock DV can fail.. Generally as the spring fatigues in it, its stops holding boost as well.. When I removed mine from my car, I found the plastic body was cracked, though I'm not certain if that was due to use or a bad installation from the factory.

 

sure your not pullin timing?

 

Thanks, I'm hoping that's the case with mine. If not, I will be back to the drawing board in trying to find this big leak.

 

My stock valve on my car seems to have gave up the ghost also - i found that it was letting air out on idle and never really closing. Put greddy type-s back on and the car felt much better. As jack said seems like the spring got worn out. Im guessing mine wore out cause its not made to work with 25psi...go figure.

 

Yeah, I'm sure.

When the leak occurs, there's a loud swishing whistle as the pressure escapes, and my boost drops all the way to 0. I use a logger to tune with my S-AFC, and on an 1/8th-mile drag run with this happening, I ran rich, which did pull some timing compared to when I'm at full, non-leaking boost, but the timing isn't causing the sound or 0 boost.

Oh, that run netted a 9.1@71 with the boost gauge reading nearly 0 throughout 2nd and 3rd, since I never let off the throttle, and the leak stayed open.

 

This happened on my car also. The entire back housing just broke right off. I think it was from putting to much force on it when installing other products. I switched over to the MR DV so I would not have this problem again. The only thing I did notice is that the MR DV gets extremely hot sitting so close to the exhaust manifold. I was thinking about making a small heat shield for it. The metel design picks up all the radiant heat in this area. The plastic stock unit never seemed to absorb such a large amount of heat.

 

I found my problem, and it wasn't the BOV. It was just the stinkin intake snorkel not being fastened down. I didn't realize those fasteners were re-usable when I installed the MBC, so I not only broke them upon removal, but also didn't bother to fasten down the snorkel with new ones.

I put on my friend's HKS SSQV while borrowing his snorkel fasteners, not knowing that this was the real problem, and everything worked great with no "leaks." I then switched back to the stock BOV and gave back his fasteners, not realizing they were needed and just assumed the stock BOV would continue to "leak" like it had before. I drove the car again and experienced the same leak as before, so that made me believe that the stock BOV was the culprit. I then read in another thread about the possibility of the intake snorkel suctioning up against the hood, so I gave it a shot. I used some non-reusable fasteners that I got from Advanced Auto, and fastened down the snorkel. Well, 'lo and behold, 1.45 bar peak with 1.3+bar holding all the way to redline in 1st and 2nd gear. Uh, wow, what a wasted week of blood, sweat, and tears. Oh well, I guess I learned how to build and use a pressure tester...and I removed some small leaks at ~15-17psi from the vaccum lines.

 

Glad you found the problem. Zip ties work well if you can not get to the mitsubishi dealer.

 

That's probaby an even better idea, since I have 100 zip ties, and they can easily be cut and replaced. The ones I got from autozone fit perfectly and look much cleaner, but they cannot be reused.