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View Full Version : IAT2 Spark Table on Supercharged Cars?



vetteboy2k
March 24th, 2012, 01:25 AM
I was wondering if there was an IAT2 spark table on the Supercharged cars like the CTS-V, ZR1, and soon to be released ZL1 that's just like the usual IAT spark table.

Figure if the intercooler coolant temps were up there GM would have to be pulling some timing and not just relying on IAT in the intake tract reading.

Is this a table that can be added if its in the tune?

Taz
March 24th, 2012, 03:49 AM
This is not my area of expertise. As I understand the control systems, IAT2 is used to monitor the air temperature within the intercooler. If this air temperature gets too high, boost pressure is then reduced in response.

I did not find a reference to IAT2 with regard to spark advance or knock systems.

Attached is an overview of the Supercharger Operation & Boost Control System.


Regards,
Taz

GMPX
March 24th, 2012, 11:09 AM
I don't think there is such a map.

vetteboy2k
March 25th, 2012, 02:40 PM
Thanks for the input and pdf, but if there was anything you come across with IAT2 in reference to anything that would reduce timing would be appreciated. Doing multiple dynos runs with a CTS-V the power seems to jump all around and thinking it had to do with the IAT2 as coolant and intake temps were pretty consistent.

eficalibrator
March 27th, 2012, 02:10 AM
The spark adder table for air temp should actually be based on calculated manifold air temp, not necessarily IAT1 or IAT2. MAT is calculated by slewing IAT against ECT to account for heating that happens post-throttle. In factory supercharged cars, this would start with IAT2 and still be subject to biasing toward ECT based on the current values in the temp bias table.