IAT Spark advance table preferences?

[viceroykarl]

Now that its getting colder out I've been making adjustments to my IAT advance tables for the colder air to add in some more timing. I'm just wondering if I should be going about adding timing this way or is it better practice to make the adjustments to the main HO LO spark tables and then have the IAT advance table remove timing for warmer temperature.

Does this IAT advance table affect the timing on the HO/LO tables or the learned values from the difference in the HO/LO spark tables.

Its probably down to personal preference but any input is appreciated.

[n0dih]

You can add some timing to it, but doesn't mean the engine will run better at it. Careful observation of the PW and Cyl Airflow and then bring up the timing a couple degrees and drive the identical drive, wind, temps, etc might tell you if you are going in the right direction.

Remember, that 1 degree too much timing (past MBT) is worse that 10 degrees to little timing. Once you pass MBT, power drops off quickly.

Greg has a good picture in his book showing the steep drop in power.

IAT and CTS timing tables are adders to the main HO and LO tables. Remember, the HO and LO tables make up a 3D table, the PCM doesn't switch between then, it makes up a new table based on them and the ASPARK PID, so think of it as a high limit, low limit and ASPARK is the % between, and that is where you are. Then the IAT and CTS and EGR and TCC and .... tables are adders to that 3D table. Think of it as a virtual 3D table, one that is formed in ram.

If you wanted to shift the whole timing table itself, you can simply add xx degrees to coolant temp vs rpm table. This would be a global shift in timing.

[viceroykarl]

Thanks for the tips. I've set up a new histograms for monitoring the injector pulse width to compare with my spark timing table that is also in an other histogram. Right now I'm mainly watching my KR and IDCs. Had to adjust some of the PE settings to get the IDCs around the 80s. KR has been pretty clean so far aside from the few random blips that peak around 1-2 deg.