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ATI P-1SC timing issues (LS1Edit)

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Old Aug 12, 2003 | 11:56 AM
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Default ATI P-1SC timing issues (LS1Edit)

First, thanks to everyone for the previous help with the tuning. I have pretty everything figured out with the exception of timing. I've done alot of reading/searching on this and other sites regarding timing, but still have a few questions. Any input would be greatly appreciated.

When making changes to timing, are we speaking strictly about the "High Octane Spark Advance" table plus knocking off a few points from the low octane table, or should changes also be made to other tables such as "Base Spark in Drive" or "IAT-MAP Timing"?

I have read that some people have zeroed out the IAT-MAP table, but how safe is this to do, provided the HOSA table is tuned conservatively?

And lastly, I have one question regarding PE. My original .LS1 file has a value of 1.1298 under the "Max Allowed Enrichment" heading. Does this value represent a max allowed modification of the PE vs. RPM values from other sources that the PCM sees. I'm assuming that this is true as in the original .LS1 file, for example, at 6000rpm the PE vs RPM lists a value of 1.2432 which is above the max allowed enrichment heading. So for GM to set the max allowed enrichment value at 1.1298 this means that through other modifications to PE at 6000 the max enrichment that the PCM can supply would be 1.4046 (1.1298 * 1.2432)? note: this is a wild *** guess, not a statement

Thanks,
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Old Aug 12, 2003 | 04:40 PM
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Default Re: ATI P-1SC timing issues (LS1Edit)

A couple of comments:

Most people modify the High Octane Spark Advance tables and allow the Lo table to cut in when excess knock levels occur. Others modify both together and find the right spot to avoid KR so the Lo table doesn't give them uneven performance.
Also, if it drops to the Lo table, it could coninue to pull timing until your next fill-up.

Max Allowed Enrichment has to do with a test used in closed loop for maximum enrichment. It's not supposed to include PE enrichment. But, this parameter still seems to be a point of confusion, even on the LS1-Edit mailing list.
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Old Aug 12, 2003 | 06:20 PM
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Default Re: ATI P-1SC timing issues (LS1Edit)

Ok,
So it looks like the majority of my spark tuning will be in the High Octane Table. I'll drop the values in the Low Octane accordingly to retain a measure of protection, should I actually get some bad gas, rather than maintain them the same.

Max Allowed Enrichment I'll leave alone.

Thanks,
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