Spark Advance
I wanted to make sure everyone had the complete picture but my snapshot of the final main spark table after the ECM modifies it exceeds this site's file size limit. Sorry about that. The mods are not dramatic but there is an adjustment for coolant temp (my example shows 154 degF) and if the throttle is over 50%, the ECM substitutes a portion of the main table with the WOT advance table (shaded yellow in example).
As for tuning your own chips, I agree with Paul that a TT chip will save you headaches but if you have the resources to mod chips and you really enjoy the learning aspect of the whole process, then go for it. I personally never liked the "black box" approach to engine management which is what prompted my research and the same with others like Eric (TT).
My 2 cents on "home made" chip changes is make small adjustments then test using a data logger. Also if you don't fully understand what the numbers are and how they're used then don't change them.
As for the main spark table, I think its been generally accepted that a few degrees can be added below 2200 rpm, a few should be removed above that (especially at higher LV8s).
Carl, thanks for digging up the 2002 post. I kept getting flashbacks of what we had to go through back then to get accurate information. Ah. the good ol' days.
Dennis
I wanted to make sure everyone had the complete picture but my snapshot of the final main spark table after the ECM modifies it exceeds this site's file size limit. Sorry about that. The mods are not dramatic but there is an adjustment for coolant temp (my example shows 154 degF) and if the throttle is over 50%, the ECM substitutes a portion of the main table with the WOT advance table (shaded yellow in example).
As for tuning your own chips, I agree with Paul that a TT chip will save you headaches but if you have the resources to mod chips and you really enjoy the learning aspect of the whole process, then go for it. I personally never liked the "black box" approach to engine management which is what prompted my research and the same with others like Eric (TT).
My 2 cents on "home made" chip changes is make small adjustments then test using a data logger. Also if you don't fully understand what the numbers are and how they're used then don't change them.
As for the main spark table, I think its been generally accepted that a few degrees can be added below 2200 rpm, a few should be removed above that (especially at higher LV8s).
Carl, thanks for digging up the 2002 post. I kept getting flashbacks of what we had to go through back then to get accurate information. Ah. the good ol' days.
Dennis
