Idle underspeed/overspeed timing question

I noticed my idle overspeed and underspeed timing changes when viewed in vcm scanner when the ac is on. It sounds great idling etc with the ac on but when you turn it off i noticed it?s not getting as much timing or retard and sounds different. Is there somewhere to change this? Why would the ac being on affect the timing at idle to be more agressive in the overspeed/underspeed? Sorry for the newb questions, i?ve been working on my own tune for a few weeks now (2007 LS2 A6 C6). I?ll post the tune here if anyone can check it out for me? Thanks in advance! Only mods are K&N drop ins, cat and muffler delete. Longtubes going on here shortly?

The extra load from A/C is enough to change the sound at an idle.

This doesn't sound like a problem

Tune and data log if you're looking for help. It's in the stickies. No one can tell anything from a cool story.

I did data log and i?m seeing much less timing advance and retard at idle underspeed/overspeed with the ac off. Thats why I?m trying to figure out what causes that.

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Originally Posted by Corvettechris86

I did data log and i?m seeing much less timing advance and retard at idle underspeed/overspeed with the ac off. Thats why I?m trying to figure out what causes that.

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Post the tune and log, on here, so it can be reviewed.

Quote:

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Originally Posted by Corvettechris86

I did data log and i?m seeing much less timing advance and retard at idle underspeed/overspeed with the ac off. Thats why I?m trying to figure out what causes that.

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Ok then try to figure it out yourself if you don't want anyone else to look at it.

Because with the extra AC compressor load at idle it will require more timing adjustment to keep the idle stable. It is not a problem and it's just doing what it needs to do to idle.