Saab APC fitted to Audi?

[urq]

... actually I posted my thoughts on SKnob'izing the MAC11/WGFV system a
while back.  The MAC-11 does also have the boost kill feature upon excessive
knock ... and that is why I go for the SKnob with WGFV rather than beefing
up the stock WG spring.  I've never had the chance to cobble together an MC
system as yet ... but what I was thinking was to create a pressure reservoir
to feed the boost side of the WGFV.  The detail that I hadn't worked out was
to find a replacement vacuum switch for the WGFV which had less restrictive
passages which would allow the pressure to be applied to the top chamber of
the WG sooner.

As to getting more info out of the MAC-11 ... talk to Scott Mockry or Orin
... they may be able to get the sort of info you are looking for out of a
modded ECU.  I've seen Scott's system on his own car ... he could tell you
the timing advance each cylinder was getting ... I'd imagine a knock light
would be pretty simple ... assuming that they are still looking for that
biz..  AAMOF, now that I'm thinking of it you could just put a comparator on
the addresses going tto the EPROM and have it detect if the regular fuel
timing map was accessed.  That sort of information can be determined fairly
easily from the QLCC code ...

HTH!
Steve Buchholz
San Jose, CA (USA)
> >
> > 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 of the equation, as it has been replaced by a pneumatic regulator a la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