im confused, it made me get more boost and worked great. how come its different for 06? is the stock as stiff as the DT? because the 04 bpv is so weak.

 

is more attention to detail in adjusting the stop for the closed postion. You can do this with the stock spring as well. The stiffer spring means that it takes more vacuum to open it, so it closes earlier in the driver demand curve. It also has a more severe transition from open to closed. A lot of people like this, a lot of them don't.

What's also true is how it interacts with the engine manegment isn't always the same, even within the same model year or ECU revision. Take two cars, that look identical, and they may not respond the same to the modification.

Matt

 

Back to the whistle........if the OEm one doesn't make as much noise I would bet that it isn't adjusted properly. It is probably letting a bit more air past the butterfly when on part throttle.

 

the DT BPV doesn't open to the same amount as the stocker. So when it IS open, the throttle body has to be at a different angle to get the same results in engine load. This could explain the different whistle. Or it could be that the DT valve makes more noise because it's at a different angle too.

The by-pass valve is in the middle of a feedback loop (driver demand, BPV, T-MAP, MAP and TB) and any change to one of them at steady state will change them all.

Matt

 

That is a possibilty, but on the few OEM ones I have seen the butterflys have all been different. Some were better adjusted than others and the sounds were all very different.

I would check the OEM bpv and check the adjustment on the butterfly.

 

Geez....This sounds similar to the problem that I am having. I installed mine on my 03 R53 last night. Lets just say I had to leave it at my parents house. Mine is making the high pitched whistling sound at idle. My idle goes up and down between 1000-1500 rpm. Tap the gas and it sounds like its going to explode. Not to mention that the check engine light came on. The odd thing is that the sound seems like it is coming from the opposite side of the car that I worked on. I'm going to try these couple things and hopefully that fixes it.

 

Well, nvm, its fixed now. Took everything apart and put everything back together. Only thing I did different was rotating the intercooler couplings around. IDK....but it seemed to work. Good thing too, cause that part definitly fixed the yo-yo effect.