%Change to AFR Ratio Table Question! (Tuning)
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From: Cheyenne, Wy
%Change to AFR Ratio Table Question! (Tuning) Ok, there are two tables to control the amount of enrichment the AFR gets at WOT...they are:
%Change to Fuel/Air Ratio vs. RPM at WOT
and
%Change to Fuel/Air Ratio vs. Cool. Temp. at WOT
Both of these tables show enrichment to add fuel at WOT of course...my question is:
Does one table compound onto the other OR, does one table REPLACE the other when values are met? For example, If I have 7.7% enrichment in the 80*C block on the %Change vs Cool. Temp Table, and then I have 3% enrichment in the 4800 RPM block on the %Change vs RPM table, does that mean that at 176*F and at 4800 RPM's my ACTUAL AFR enrichment is 10.7% at WOT for those blocks??? Or does the RPM table take over once its conditions are met, so say it runs 7.7% up until 4800 RPM's, then it drops to 3% until another change happens, or vice versa??
%Change to Fuel/Air Ratio vs. RPM at WOT
and
%Change to Fuel/Air Ratio vs. Cool. Temp. at WOT
Both of these tables show enrichment to add fuel at WOT of course...my question is:
Does one table compound onto the other OR, does one table REPLACE the other when values are met? For example, If I have 7.7% enrichment in the 80*C block on the %Change vs Cool. Temp Table, and then I have 3% enrichment in the 4800 RPM block on the %Change vs RPM table, does that mean that at 176*F and at 4800 RPM's my ACTUAL AFR enrichment is 10.7% at WOT for those blocks??? Or does the RPM table take over once its conditions are met, so say it runs 7.7% up until 4800 RPM's, then it drops to 3% until another change happens, or vice versa??
On The Tree
Joined: Oct 2004
Posts: 145
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From: Everett
They compound onto one another. Most leave the Coolant Temp table alone and only adjust the RPM table. The Temp table holds the baseline constant under normal operating temps, the RPM table makes small adjustments from there.
You may find this helpful: http://www.jonaadland.com/Z28/AirfuelcalcPredict.xls .
I didn't originate that but I did add the predictive part--enter your current PE values, enter what you want the AFR to be at each RPM, then enter wideband results you get on a pull and it spits out what your new PE table values should be. It still usually takes a couple iterations but can save some time so you aren't spending time banging on a calculator while paying for dyno time.
You may find this helpful: http://www.jonaadland.com/Z28/AirfuelcalcPredict.xls .
I didn't originate that but I did add the predictive part--enter your current PE values, enter what you want the AFR to be at each RPM, then enter wideband results you get on a pull and it spits out what your new PE table values should be. It still usually takes a couple iterations but can save some time so you aren't spending time banging on a calculator while paying for dyno time.
