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Old 07-25-2008, 02:27 PM   #1
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Default Quick question about Gair

Should the Gair value in my data log at a given temperature match the value in my airdenfactor.inc?

-Mike
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Old 07-25-2008, 03:25 PM   #2
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it should, but mine never seems to.
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Old 07-25-2008, 07:00 PM   #3
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If your IAT/CLT-related air-density corrections are active, that will throw it off.

I find that mine bears not resemblance at all to what's in my airdenfactor.inc, even outside the correction range, which makes me think that my MS was never properly easythermed. If that's the case, it would explain my long-standing weird leaner-at-higher-temperatures (without heat-soak) behavior, and the fact that my maps never look anything like other miata maps I see posted on here.

-Mike
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Old 07-29-2008, 03:08 AM   #4
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Quote:
Originally Posted by Braineack View Post
it should, but mine never seems to.
How far off is it? Do you think maybe it's reporting a raw ADC value or something else strange, and not the actual percentage?

Can some other people on here chime in? Just load up an older datalog, pop up MAT and GAIR, and open your airdenfactor.inc in notepad, and just scan through it to see if the numbers seem to make sense.

-Mike
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Old 07-30-2008, 03:51 AM   #5
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I played with this some more tonight. I found that if you have IAT-based air density correction enabled, it applies the correction at the lowest temp entry to all temps below that. Ooooops. I fixed that (so the lowest temp entry is 100), and also I re-easythermed my code, and reflashed it, and between those two things, my Gair now perfectly matches what's in my airdenfactor.inc.

-Mike
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Old 07-30-2008, 09:57 AM   #6
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ill have to go back and look....
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Old 07-31-2008, 03:10 PM   #7
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Bump for update. I'm curious what you had yours set to. And given the number of people who are probably running your IAT-based correction verbatim, we need to know.

-Mike
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Old 08-15-2008, 11:23 PM   #8
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You know what, looking at my logs, my Gair sits at 93-94 regardless! Since I went to high res it can idle at 16-17:1 so i never really paid attention to my AIT corrections, but they arent working.

I changed it over the clt-based for a few seconds and it jumps to 130 in my logs and all the way down to 12:1. So AIT-based doesnt seem to even be working for me....odd.

my map is setup like this:

70 100
85 100
90 102
95 104
100 110
120 115
160 140


at 111*F after heatsoaking, it was pegged at 94 Gair, not sure why....
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Old 08-15-2008, 11:34 PM   #9
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seems I found the answer:

[CurveEditor]
curve = clt_IATCorrC, "Coolant corrected Air Density, see Settings", 9
topicHelp = airdenHelp
columnLabel = "Temp", "Offset"
xBins = IATCTemp, mat <==change this, previously 'clt'
yBins = IATCorS
gauge = matGauge <== also change to this if it doesn't say this already
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Old 08-16-2008, 11:25 AM   #10
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this is something i always found strange, now with those changes it will now relate clt and mat, and the gauge will show mat in the window? if so i can see that being much more useful, like when clt is 85 and mat is 123, now it would actually make sense
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Old 08-16-2008, 02:31 PM   #11
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yeah it puts the MAT guage in the window so you can acutally see what they are.

It's working, and I think it always was, however I needed to start corrections at 115*F.

so my table is something like

90 115
95 120
100 125
110 130
120 145
160 150

it's working perfectly like that...dunno why the numbers need to be so high, but it's working....let it sit in the sun with the fan blowing and got the AIT to read 120*F before I cranked it, Gair logged 115% and my AFR when i started was a low 14, not a high 16....
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Old 08-16-2008, 04:48 PM   #12
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awesome maybe i can finally get this working now
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Old 10-08-2009, 09:04 PM   #13
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i'm still having issues with Gair / iat corrections..

my opinion is that the airdenfactor.inc is too strong?

My MAT and CLT seem to be displaying correctly in megatune, but i notice (like others) that the 'tune' changes with the temperature...

I can dial something in at warm temps, and then if the temps drop 20 or 30 degrees and i run a new log, practically everything will need to be leaned out by a few percent..

i understand that the "coolant corrected air density" should allow you to compensate for this, but isn't that just a hack?

would it be better to just flatten out the corrections in the airdenfactor file and re-flash?

fwiw i checked a couple of air temps and the airdenfactor file certainly appears to be correct in its math, but it just appears to make too much of a difference!!
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