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b4pjs
August 17th, 2015, 08:16 PM
Just starting out with this whole tuning malarkey, but I have a question on which IAT is used to modify spark timing in tables {B5107}, {B5108} and {B5109} . I would have thought IAT2 should be used, but just want to confirm that this is the case. The link file references SAE.IAT, but IMO, the GM engineers should have used IAT2 as that can be considerably higher than IAT1.


;IAT Spark Table
B5107.ROW=SAE.IAT
B5107.COL=E67.APCYL_DMA

;IAT vs RPM Spark Multiplier
B5108.ROW=SAE.RPM
B5108.COL=SAE.IAT

;IAT vs ECT Spark Multiplier
B5109.ROW=SAE.ECT
b4pjs
August 17th, 2015, 08:37 PM
Just to add, car is a stock VXR8 GTS LSA.
joecar
August 18th, 2015, 09:00 AM
You can add GM.IAT2 by using comma as a separator...

e.g.:



;IAT Spark Table
B5107.ROW=SAE.IAT,GM.IAT2
B5107.COL=E67.APCYL_DMA

;IAT vs RPM Spark Multiplier
B5108.ROW=SAE.RPM
B5108.COL=SAE.IAT,GM.IAT2

;IAT vs ECT Spark Multiplier
B5109.ROW=SAE.ECT
B5109.COL=SAE.IAT,GM.IAT2


when you hover your cursor over thes IAT axis of those tables, a yellow tip will popup showing you the alternate link pids...

so you can log either pid...

I'm not sure what happens if you log both, I think the first pid mentioned has precedence, if so then reverse the order of the pids shown in the example above.
b4pjs
August 18th, 2015, 05:35 PM
Good information, but doesn't answer the question on which the car actually uses internally. Would it be possible to work out?
b4pjs
August 18th, 2015, 07:40 PM
Will change it to IAT2 anyway as that is the hottest of the two.
joecar
August 19th, 2015, 03:04 AM
Good information, but doesn't answer the question on which the car actually uses internally. Would it be possible to work out?I don't know the answer... is there any DMA pid for dynamic air temperature...?
b4pjs
August 19th, 2015, 03:07 AM
I don't know the answer... is there any DMA pid for dynamic air temperature...?

Just found GM.DYNAIRTEMP_DMA. Will log that and see what it gives compared to the IAT's :)
b4pjs
August 19th, 2015, 08:15 AM
Just found GM.DYNAIRTEMP_DMA. Will log that and see what it gives compared to the IAT's :)

Hmmm, cannot find it in v8, but have added it to options.txt, so will see if it logs...
joecar
August 19th, 2015, 08:39 AM
Just found GM.DYNAIRTEMP_DMA. Will log that and see what it gives compared to the IAT's :)If that pid is loggable on E38 or E67, then add it to the link .ini.

( I think that pid may be LS1B only )
b4pjs
August 19th, 2015, 08:55 AM
If that pid is loggable on E38 or E67, then add it to the link .ini.

( I think that pid may be LS1B only )

Doesn't seem to log on E67. More research needed. IAT2 makes the most sense, but spark timing doesn't seem to correlate. Will get a nice long log on Friday to test my theories.