skip the IR models for tires
Skip trying to use an IR model for tires. For $100, you can get a proper unit for this application:
http://www.longacreracing.com/catalog/item.asp?id=200&catid=7
The IR units are good for shooting rotor / caliper temps and things you can't reach easily, like headers, etc.
They complement each other.
For tuning, I use these:
http://www.longacreracing.com/catalog/item.asp?id=188&catid=7
http://www.longacreracing.com/catalog/item.asp?id=210&catid=8
...along with a decent stopwatch for "roundabout" measures during a session and a Hot Lap timer for the driver to get in-car feedback and for review once a session is over (transponder times from an AMB system aren't always available on testing days).
Having the memory functions on the units isn't a luxury for me... it's a necessity. I may measure 3-4 sets of temps during a 20-30 minute testing session... yes, I can write them down after each measure, but I also have to time the car and talk to the driver.
When I get back to the paddock/garage area, I review the saved numbers and put them into a spreadsheet along with other data, including:
Spring rate
Damper settings (high speed compression, low speed compression and rebound)
Swaybar type and setting
Track temperature (good for measuring with an IR pyrometer)
Ambient air temperature / humidity
Alignment settings
etc.
etc.
All this data is tracked and logged and small adjustments are made between sessions to try and accomplish several things:
1. get the car neutral throughout the phases of a corner, or sometimes a slight oversteer tendency
2. get the tire temps even across the face of the tire
3. get the tire temps into the optimum operating range for the particular tire we are running
4. get the tire pressures at the right level for the tire type and vehicle weight at each corner
5. most importantly... reduce lap times
Understand that this data is ultimately to be combined with logged data coming from a data acquisition system, which gives insight into a LOT more about what's going on during a lap that leads to the after-the-fact results that you read with tire temps and pressures. This stuff (suspension travel, brake force, Gs in a turn, etc) aren't that important for a weekend track junkie, but the tire stuff above absolutely is.
EDR