Knock with SAAB APC

[Jim Green]

--- denis <sparkplugvw at hotmail.com> wrote:
> I know APC from SAAB is for light boost, but it s a
> good way to prevent the engine to melt...
> 
> So guys who change spark advance with Javad or
> Megaspark or electromotive or what ever ECU how do
> you metering the knock to prevent problem ?

Denis, check out this website.  It's great for tunning
info.

http://members.aol.com/dvandrews/ems.htm#timingadjust

All of the engines with forged pistons are pretty
knock resistant, so if you hear in ping a few times,
you're probably OK.  Now, your head gasket will take a
beating, that's why I run the all metal 20vt HG with
ARP head studs.  

Now, the goal with the Saab APC is to tune the engine
so you don't see the knock light going off.
(obviously).  Initial tune you'll probably get few
audible knocks which are OK as long as you're only a
few degree's off, just start to tune them out till
your light doesn't blink anymore, and don't keep your
foot in the gas.  It will catch knock that you can't
hear, so trust it.

Once you have it tuned, as long as you stick to the
same grade of gas you'll be fine.  Worst case is you
have to bring along the laptop when it's really hot or
really cold outside to tune for temps that were not
available the first time.  You'll brobably find that
you'll want to back off base timing a degree or two
from "the ragged edge" just so you're covered for
things like bad gas, heatsoak, stuff like that.

HTH,

=====
Jim Green
'89 80q ... slow
'89 90tq .................fast
http://www.mswanson.com/~jgreen/car_home.html

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