Thread: Pulley / Timing / MAF tuning with elevation change

Hello everyone, moved from MI to TN recently, haven't been on much, figured I'd check in with a few questions.

I'm hoping the tuning section has maintained it's integrity, some of the other subforums seem to have fallen into disarray since I left, with responses on par with Yahoo Answers. lol

Anyway, I last tuning my car in Grand Rapids, MI area. I have now moved to TN. According to "the net", I am 400 feet higher above sea level than I was. (650-700ft to 1000-1100ft). Also, the temperature down here is roughly 20-30 degrees higher on average than it is in MI. I'm assuming that the relative humidity is fairly similar.

Using this information, I've calculated that the air is roughly 4-5% less dense here. Seems pretty negligible, unless there are other factors at play here. Does that almost directly equal a 5% loss of power, everything else being equal?

People talk about dropping whole pulley sizes in the summer, even at the same elevation, so it would imply that there is more than a 5% difference. I would imagine that that small of a difference could be made up with 1-2* of timing at most.

Any ideas as to what I should expect as far as re-tuning goes?

The general rule is 1000ft costs 5hp it never hurts to see where you are in terns of your ve fuel trims and maf but they should still be realitvley close assuming you had your tune spot on in MI. so whatever you can't get away with in regards to dialing in fueling vs. Your timing vs. Kr you should try to achieve

Are you running closes loop?

Yes GTPpower, I am running closed loop.

Darkhorizon, I suppose I misunderstood how a MAF works. I thought that the output signal changed with velocity of air moving past the filaments, rather than the density.

And 5hp for 1000ft? Doesn't sound like I need to change much, really. Probably just overthought this. Thanks all!