Saab APC fitted to Audi?

[auditude at get.net]

urq urq at pacbell.net wrote:
>
> AFAIK the MAC-11 lights the check engine light when knock is
> detected ...

My undersstanding is that the check engine light only goes on after the ecu
cannot back off timing any further to prevent knock.

My question about connecting to the stock knock sensor system, was
because I thought I recalled someone here on the list, or more than a couple
people, finding a way to somehow tap into the stock ecu's wiring or circuitry or
something, to actually get a visual display of when knocking occurs. (before
max retard is reached in this example)

> while I've contemplated the APC solution on my KS-deficient WX I've > gotta wonder why anyone woiuld even go to the trouble of fitting
> one to an MC ...

My question was for an application where the stock WGFV was no longer part
of the equation, as it has been replaced by a pneumatic regulator a la
SchrapnelKnobben mod.

If I fit an APC computer, then I will have knock sensing boost control, from
what I can tell.  Currently, if I tried, I could get it to knock, and the ecu can't do
anything about it.  With the APC inline with the upper WG chamber (still not
sure if this even applies, but it seems to), it would detect the knock and divert
pressure away from the upper chamber, thus reducing boost.

That's what I was thinking anyway.  If it doesn't work in practice, that's another
story.  I am just trying to find out if there are others that have tried this.

As you know, the stock ecu prevents/responds to knock by retarding timing,
which adds heat and reduced power.  The APC prevents catastrophe by
reducing boost.  This may be more beneficial than keeping the boost too high,
and compensating by over-retarding the ignition timing.

Do you think it would have an application in a Schrapnelknobben/upper WG
chamber regulator-mod type setup?  I think it would add a measure of safety,
while retaining the other benefits of that mod.  If it worked.

What's the KS mean?  Is that a reference to the three parameters on that
APC site?  I don't recall what they were, and my mouse isn't working right now
so it's not convenient to go browsing currently.  Spark advance and pressure,
or something like that?  Or was the KS something totally different?

Later,

Ken