I'm a bit stumped on a seemingly odd trend I've noticed in observing my boost levels in relation to throttle input: Roughly the first 1/4 of pedal travel is off-boost, with the next 1/4 travel yielding steady increase in boost from 0-10psi. After that, it hangs at 10, often fluctuating between 8 and 10, until I get to just about WOT - Then it jumps up to 15 and holds steady. Now, the fact that it will hold a steady 15psi (with a 16% pulley) seems to tell me that the BPV is not failing... But the sort of "lag zone" in the latter half of throttle application is still puzzling, especially since the indicated boost level fluctuates. Is it possible for the thing to be sticky or something?

 

It is possible that the bypass valve doesnt want to close all of the way, the return spring isnt super strong. Before you go to crazy try zip tying the BPV shut and doing a few pulls like that, forcing it shut wont hurt the engine and I dont think it will hurt the valve.

 

I presume it's easy to get at? Perhaps I'll have to take another look-see at that there manual.

 

The BPV on my Mini got sticky and would not close all the way. This is a common problem. I had to have the valve replaced.

 

Not 100% sure on that part. You might need to remove something simple like the intercooler cover or the rubber intake tube. Check realoem.com if you want to know right away.

 

When I ziptied my BPV closed for some playing, my CEL came on... after I removed the ziptie, the CEL went away.

YD

 

It seems to close all right - Boots drops off pretty much the instant I lift, and it even gives me a nice crisp "psh" sound reminiscent of a BOV. I rather enjoy it . What I don't enjoy is fluctuation in my boost level at 3/4 throttle. Maybe I'll take the thing out this weekend and play with it.

 

I was just talking about this (somewhat off topic) on the ecu reset thread. I had a spark plug blow out on me about two months ago and I got it all fixed but after that the car started exhibiting a very severe hesitation under acceleration. After talking with some guys I realized that its probably the valve because the car accelerates without hesitation during light throttle but anything past light the car stutters and jerks until about 4000 rpms and then it clears up and accelerates like normal. I dont have a boost gauge so i can't tell ya about that part but if your car is hesitating and the such (feels somewhat like a misfire but no CEL) you probably have a bad bypass valve. My car is still under warranty but I was going to pick up a DT one and just screw the dealership. Hope this helps ya out.

Steve

 

No real hesitation, unless of course the stupid TC comes on like it always seems to with the shedload of sand still on the roads around here (thank goodness I finally got my circuit to auto-disable it in). It's more in the 3/4 throttle range, and I wouldn't really call it a hesitation, persay... It's just sort of like that last 1/4 of the pedal throw has no effect on power, until you hit WOT. I brought it up with my SA last time I was in there for a seperate issue, but we agreed that it would hold full boost and left it at that.

 

Ahh, I know what you are talking about with the pedal travel. I have the same deal on my stock 05, the first 2/3 of the pedal travel is where 90% of the modulation seems to be, that last full third gets you that extra 10 percent or so. I just accept it for what it is, I dont have to move my foot as much now to go fast.