[s-cars] Cheapest boost controller evar!

[FvAMI at aol.com]

In a message dated 2/3/04 7:31:11 PM Pacific Standard Time, 
calvinlc at earthlink.net writes:


> It's a heck of a lot easier and more reliable to build one with a 555 timer
> that puts out a set duty cycle at the same frequency as the ECU WGFV signal,
> the output is enabled by a simple comparator tied to the TPS, so it's not
> doing this all the time, only above a certain throttle input.  
> Obviously a
> FET power stage is called for.  You vary the duty cycle, and therefore 
> the
> boost, by varying a pot in one of the numerous punch outs not used beside
> the rear defroster switch, etc.  I am doing something like this as an
> experiment on my '89 200 wagon.  I have tried it temporarily and it 
> seems to
> work quite well, I just haven't soldered the stuff down yet.
> 

There you go!

This is one of the better ways to do it. Even better would be to also 
modulate the actual pulse duration of the 555 which becomes quite complicated. 
(similar to the Motronics and Apex units).  I am sure this would be too much 
for the guy with only the relay.

Best regards,
Feico van der Laan