Spark advance tuning made simple and quick?

[Dave Zug]

Whasa KPA ? ;-)

I think (from reading ECM and otherwise) that optimal spark timing has less
to do with knock threshold and much to do with power output. Obviously if
you get the best power under a knock condition then you still want to back
off, but a 383 and 377 (popular article I read) performed best at 36
degrees. Take a look at the "dyno version" ARAP for the '165. See what they
came up with as "optimal" for the TPI 350. I've taken the approach of
increasing WOT advance 1 degree per track visit from 30 to 36 (or beyond)
until the car starts to lose E.T.  for part throttle its a different
game.I'm thinking. You must either maintain load and allow RPM to slowly
increase, or maintain RPM and allow load to change... thru several
iterations you can find the knock areas... alternatively you can drive
around normally while constantly recording and run the recordings thru a
utility to spit out the 'attention' zones (or just manually find them). I'll
probably stick to ARAP with high-delta-LV8 (producing knock) based spark
tweaks and WOT advance tweaks based on E.T. result.  So far, on the BFG
drags, I have not had to manage the torque at launch, but I plan on dropping
launch zone spark if it comes to it.

I better start keeping some secrets - the ears of (the local racers) MAFB
are on the list now ;-)  of coarse I could be making all this up ;-))


----- Original Message -----
From: Walter Sherwin <wsherwin at home.com>
To: <gmecm at diy-efi.org>
Sent: Friday, September 29, 2000 8:23 PM
Subject: Re: Spark advance tuning made simple and quick?


> Sounds like something that would be of interest to both the GMECM and DIY
> crowds.  Why not maybe paraphrase things in a short E-Mail to the list(s),
> and then later as time permits develop your website and let us know where
> its located when done.  New/different/bizarre ideas are oft the fodder of
> what has not as of yet been conceived.............
>
> Walt.
>
>
> > Gentlemen, I have an idea that may save tons of time when tuning spark
> > advance. In general, I have a very simple way of manually adjusting
spark
> > advance a known amount on the fly while driving. That way, you could set
> the
> > entire SA table to say 25 below 60 KPa and say 5 above 60. Then, you
could
> > drive at known RPMs and MAPs and just manually dial up the SA while
> listening
> > or watching for knock counts on a scantool. Once you hear or witness
> knock,
> > just write down where on the RPM vs. MAP map it occurred and how much
> advance
> > you had cranked in and how much you backed out. Then, its just a matter
of
> > reburning the chip one time with the results of the run. If there is any
> > interest in this procedure, I'll write it up in a website with digital
> photos.
>
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