730 Spark Advance

[Squash]

1.  I think that you add the SA table value and the initial advance to get the real at-crank
advance.

2.  42 maximum +6 initial would be 48 degrees, but i'm not sure this is correct.  I think it
actually takes the initial spark into account.  There isn't any tuning reason to know the initial
spark except for this and for ALDL output.  I've never had to go up that high so I can say from
experience how it works.

3.  I'm not using this mode, but 31+6 would be 37 at cruise, a more "realistic" number, whatever
that is.

It's been a couple of months since i last tuned my sparks, so forgive/correct me if this is false.

Squash

--- Bob Valentine <bob at tecmark.com> wrote:
> I'm doing some last minute tuning on the spark tables, and need to get a
> few things straight.   Base cal is AUJP.
> 
> 1.  The actual measured timing at the crank is the amount in the table (32
> degrees for example), subtracted from the inital advance (6 degrees in
> AUJP).   Measured at the crank, this would be 26 degrees?    This is what
> the scan tool reports as spark advance. 
> 
> 2. Is the value for max advance at $026 is the max advance the ECM will
> allow to be delivered, or the max value allowed in the table?  Given that
> $026 is 39 degrees, the max advance possible measured at the crank would be
> 39 + 6 = 45 degrees?      If this is correct, a value of 42 degrees in the
> table would result in 38 degrees crank advance, right?
> 
> 3.  What are average highway cruise SA numbers?  I realize this varies
> greatly, but what's a ballpark?  Stock AUJP table looks to only put in
> about 31 deg. at highway cruise, less than I'd expect.
> 
> 4.  Is there a good reason to use "Hiway SA mode" instead of just directly
> tweaking the spark table?   
> 
> -> Bob Valentine
> -> bob at tecmark.com
> 
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