[s-cars] Cheapest boost controller evar!

[FvAMI at aol.com]

In a message dated 2/3/04 11:32:33 AM Pacific Standard Time, gabriel at ts.bc.ca 
writes:


> Interesting read.  http://forums.audiworld.com/9080/msgs/155994.phtml
> 
> BigMouse has 200 20vt in his Audi 80.
> 
> 
> 
> 



Give someone a volt meter and a couple of electronic components and this is 
what you get.

1) Relay trip voltage varies and holding voltage is much lower than the trip 
voltage. So even if you got it to trip at the 4.5 volts the input voltage 
would have to drop to maybe 3.5 volts before the relay would open again. You 
should build a circuit that uses a comparator with a little hysteresis in it. 
2) Use a comparator and a Power FET and get rid of the relay all together. 
More reliable.
3) This circuit will create boost oscillation. Wastegate is on or off - you 
will need to adjust the response time (slow it down) to get more of an average.
4) All fail-safe boost cutoffs are gone.

But in theory this is what boost control does. Along with algorithms to 
prevent boost overshoot and undershoot ... etc. That is why external boost 
controllers have a learning mode and cost so much.

This would be a great boost oscillator.

Best regards,
Feico van der Laan