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Old 09-13-2007, 11:48 AM   #1
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Question Temperature compensation?

Is there a trim setting for temperature compensation in the MS? Here is my problem. I tune the car while it's 80 degrees out and it runs great achieving all my AFR targets. Then I drive the car when it's 70 degrees and it's rich all over the board. So I tune it at 70 degrees and it's rich when it drops to 60. 53 degrees last night was interesting.

Running the 94/95PNP with the IAT sensor, no MAF. The IAT sensor is mounted in the intake charge piping after the intercooler, about 8" from the throttlebody.


Also, should the various settings be on Speed Density not Alpha-N/Hybrid Alpha-N? From what I took from the manual I thought Alpha-N or Hybrid would be correct but when I chose it the program loaded with warnings of lots of errors so I set things back to Speed Density. When I flashed my MS a few weeks ago to remove the MAF various files were missing for the flashing to occur so I just copied said files from the "with MAF" folder.
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Old 09-13-2007, 11:54 AM   #2
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use clt related air-density, go under advanced and change clt to ait.
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Old 09-13-2007, 11:59 AM   #3
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Advanced > Coolant related ari-density > settings > coolant corrected air density ?

then change "Normal Correction" to "Corrected"
and Correction Based on to "IAT Corrected" ?
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Old 09-13-2007, 12:02 PM   #4
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Quote:
Originally Posted by paul View Post
Advanced > Coolant related ari-density > settings > coolant corrected air density ?

then change "Normal Correction" to "Corrected"
and Correction Based on to "IAT Corrected" ?
exactly, tho I don't get the issue you're having, you'll have to set the range of correction to span the whole revrange.

I use IAT based compensation between 500 - 1500rpm to cure a lean condition on hotstarts as the standard compensation is faaaaarr too agressive.

I initially nicked someone elses settings which worked okay, but I've since spent some time tuning them further, and I can honestly say I've never been happier with the way the car runs now
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Old 09-13-2007, 12:29 PM   #5
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I understand that air temp decreases it becomes more dense. so the colder the air is the more fuel you need to maintain the same AFR, correct? It seems that it's adding too much fuel as the air temp drops so when if I tune my car when it's warmer it runs richer when it's cooler.

So after changing it to IAT corrected should I be experimenting with the "Offset(%)" settings for each temp input?
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Old 09-13-2007, 01:05 PM   #6
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Quote:
Originally Posted by paul View Post
So after changing it to IAT corrected should I be experimenting with the "Offset(%)" settings for each temp input?
both, it's intorpolated into a curve tho, so use break points for the temp, and go from there.
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Old 09-13-2007, 01:45 PM   #7
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Its wierd that the car richened up when it got colder... typically it leans out...
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Old 09-13-2007, 01:47 PM   #8
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ive experience the same, leaner at high temps....
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Old 09-14-2007, 05:05 AM   #9
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Quote:
Originally Posted by Splitime View Post
Its wierd that the car richened up when it got colder... typically it leans out...
It happens because the default temp compensation curve is too agressive.

I can understand why though as it's far safer to be to rich than too lean
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