Thoughts on not using Fuel Mixture Spark Correction

[cmitchell17]

I zeroed out mine on my 5.3 and it seems like it will be a lot eaiser to tune spark now.

F-Bodies and Corvettes don't use them and they go into PE instantly and so do I.

What does everyone else think about it?

And ive always thought a richer fuel mixture (12.5-13) burned slower, which required more timing thats why there was a fuel mixture spark correction table)

But after reading more a richer mixture burns faster while a leaner burns slower?

[Redline Motorsports]

Personally I think its micro managing at its finest!

At "normal" WOT AFRS (12.4-13.0) I don't see timing corrections making a hill of beans difference. However they way GM calibrates WOT fueling with 10.9 AFR (on the new ZO6) to 11.7, I can see the possible advantage of playiing with spark. The tables most likely benefit them and not us doing "custom" performance tuning.

Many times I have chased my ass around trying to figure out why my timing is higher then the High Oct table only to remember about this adder. We never had it before and we tuned fine so why add more fuel to the fire!

The filp side is that it could also be a cool what of fine tuning in reverse. Since its based upon rpm, as long as your "commanded AFR (or EQ) is in line, you could use this table to add or subtract timing at given rpms. Mant times with the E38 the PCM commanded vs actual might not be as close as we are taught to do. This means that table can be mislead.

Just my .02!

Howard

[cmitchell17]

On the Gen IIIs they don't use them at all. But the Gen IVs they use them less and they also go negative(-1,-2) and positive(+1,+2) and stay at zero in some places.

I mostly zeroed mine so I could run a 70-100% blend of my optimal timing table. I left the light load and high load low rpms (2000-) stock to prevent knock when the TC is locked under load. Then bleneded a 70-100% advance from the optimal timing table.