Re: 749 Question

[Dig <turbodig@yahoo.com>]

----------
>Barry Writes:
Subject: 749 question -
Twiddling the dials on my 749 on the bench, I notice
that decreasing MAT
values past 60degF or so, results in increasing BPW -
logical to expect
that, but gives no change on increasing from 60deg to
the max.
Spark timing is also affected (same temp ranges), but
I can't find either
the MAT timing bias factor (KMATBIAS) in Promgrammer
or in GMECM; neither
is there a table giving timing vs MAT values (to be
offset against the bias
figure).  I thought at first that the SyTy code didn't
use MAT for anything
- - am I missing something here?
----------


It uses it for a number of things. Notably:  

The F3 table- Spark advance adjustment vs. ADMAT1K
and BSTPRES

Starts at $C2D2, continues to C2FE. This one's
handy because you can kind of use it as a mechanism to
retard timing in 3rd or 4th gear. (Since MAT 
increases quite a bit in those gears) It's a 5x9 
table with ranges of Cold, 23.5C,49.3C,80C, and HOT.
Boost is 0-100 KPA. 

$39 = 0 correction, anything above that advances  
timing, anything below retards. I set the 80C and 
hot sections to retard 4-5 degrees, the rest I just
leave alone.

 
F31M: Base Pulse Inverse Coolant Term Vs. ADMAT.
17 values, beginning at C4D1. It goes in reverse,
Hot is first, Cold is last.

It's a table of contributor values to the overall
fuel equation. Interesting you mentioned 60 degrees,
the values are all the same until the MAT drops below
60. It must be working. :)


There are others, these are the biggies, though.


Later,

Dig

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