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Discussion Starter · #1 ·
I was tinkering arround today and decided to test the voltage the ECU was sending to the BCS. I was consitering installing a switch to eliminate computer control of the solenoid, but i dont know if this would have any negative effects.

Basicly I found that at idle, the computer sends .5V to the BCS. When you rev the engine, the voltage climbs, sometimes up to 6 or 7 volts, and other times only to like .7V. I think this is probably because of the knock sensor, or just the computer being stupid, right?

Why would the computer send such a low voltage to the BCS at idle, and why would it change with engine speed? Is the computer trying to make throttle responce more linear?

I think i really need someone to explain how the BCS works. As i understand now, the wastgate opens at 6psi, but the BCS ups that when the conditions are right, up to like 8.7psi i think. So does that mean at 8.7psi, the comp is sending 12V to the BCS? If i put a manual switch on it, will the turbo spool faster? Is there anything negative about having a 12V source applied to the BCS all the time, besides the knock sensor not being able to lower the boost?

Any info would be helpful, I'm trying to better understand my car.

first thing i did was tear the BCS off and install an aftermarket one.

i'llbe investing in a A/F meter and EGT gauge soon to give me more indication of whats happening under there.

also i'm trying to work out how to hook the knock sensor up to a small light so it will illuminate when knocking is detected...but this seems alot more complicated then it sounds because my understanding of knock sensors is that its basically a microphone which send its signal to the ECU that then determines what is 'knocking' and what is background chatter....

any ideas there?
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