bypass valve response

[LoukakIS]

Hello again! My 318is is already supercharged, and is running well the past few months, but I need some advice for my supercharger bypass valve.
I'm using the OEM bypass valve that mercedes was using before I put it on my BMW, but the valve response is terribly slow.
The valve has a spring that keeps the valve open when no current is applied, and (as vivid workshop says) Mercedes uses a square pulse to control its possition. The problem is that the valve does not stay in a standart posittion for a given pulse. For examlpe, if I give a 30% pulse lets say that the valve closes 60%. If I leave the throttle (valve 0% close) and give 30% pulse again, the valve closes 40% the second time. If I do the same but with a time differense, the valve closes again 60% the second time. The valve motor has 2 pins, 12V and ground, I connected the ground to the boost pin output on MS3X. I measured the 2-pin voltage differense with my oscilloscope, and I have got the following (triangle) voltage output. What can I do to improve the valves reaction? I'm thinking to use a BIP transistor, intead of the boost output.

Here you can download the msq(https://www.dropbox.com/s/dusjh13wjtuwd ... .37.31.msl)

Thanks for your time, Konstantinos