Wrong spring in Tial BOV = boost creep?

[scheides]

So I've had this boost creep issue since I installed the internally-gated bastard20g on my car...or was it longer? Thinking back to my 16g, I recall seeing my boost gauge reading way higher than where I had set my mbc at during some high-rpm jaunts, but I chalked that up to extremely cold weather (-20 or so). I have replaced all of the vacuum lines on the motor, and done several boost leak tests.

I already have a free-flowing exhaust on my car, but after getting one of the LSE/LIPP O2 housings on the hotside of the turbo, I really started to question the wastegate actuator, thinking it was just kinda sticky.

In the meantime, I have been running a nice mix of bobby and steve's 111 pump and 92 so that I can boost 24-25 psi daily, so I could really have cared less about the boost creep issue. 16g's and 20g's have so much torque at 4500rpms at high(er) boost it is just plain fun!

Anyways, I have always noticed this hissing sound from my tial bov while at idle. Is it possible it has the incorrect spring in it, and that, just like at idle, at 5500+ rpms the BOV is leaking slightly?

As a result my mbc (which is T'd from the same vacuum hose) could be seeing incorrect manifold pressure, right? I know it's not ideal, but I ran a second vacuum hose directly from the manifold to the mbc, and voila, 20-21psi at redline instead of 23-25!

Somehow, I'm just a bit sad, I'll miss "having to" run all that boost and high-octane gas... :(

[1ViciousGSX]

Is the sealing ring installed?

[scheides]

Hrm, not sure. Where does it go? It does not leak between the pipe and BOV, the BOV will actually partially open while the car is idling.

[GVR-4579]

well for one i personally dont like running the BOV and the wastegate on the same line.

as long as you are recirulating or have a non mas air metering system it wont hurt that it is open at idle.

ok now back to the vaccum line setup, i dont like it because you are loosing pressure thru the mbc and then your bov does not see max pressure top side to hold it shut, however i think it would effect you boost negatively not positively unless the wastegate diaphram is ripped wich it cannot be if it will open at idle from vaccum

a bov shouldnt really take any pressure to run, all of them i have seen are sealed units and should not leak pressure or vaccum on the diaphram side

hopefully some of that will make sense, or atleast help some

[Shane@DBPerformance]

I tuned a DSM the other day that had/has bad creep problems even with a Tial 44mm wastegate mounted at the collector. It didn't help that the car wanted to knock, so we had to run fairly low timing, which results in even more boost. I ended up moving the vacuum/boost source line for the wastegate from T'd into the Greddy BOV's line to it's own dedicated line off the intake manifold. The boost still creeped, but it ended up being at least 4 psi less across the RPM range.

[scheides]

Interresting. I am seeing similar results: probably 2-4psi less with a dedicated line.

[blageo23]

This time I did my engine I ran seperate vacuum from the manifold to the BOV and then from the Jpipe to the WG. I noticed that the car hits boost better and the BOV is like 100 times louder(which the ricer in me LOVES!). Also if you like running high boost from boost creap why dont you just turn that little knob and run like 30PSI :).

[96 Gsx Awd]

I had this same thing happen so i ran higher boost. AND now my car is sitten in my garage crying because it has a big whole in the block. So be carefull how much you boost on stock internals. (Thats why i bought je pistons and eagle rods now to boost high =)~