Last month in the article about the UFR late model racing for the first time Bob said the LF tire temps were lower than the LR temps.  He said he raised the rear track bar to keep the rear from out rolling the front and it evened up the left side temps.

I am a little confused about what raising the track bar actually does.

If you raise it you raise the rear roll center...but everyone says that when you raise the track bar you actually loosen the car.

Can someone please explain in more detail why he raised the track bar and more importantly why it raise the LF temps.  And why it didn't cause the car to get loose?

Thanks.  

I can visualize this in my mind, lets hope I can express it!

If the track bar was too low, the rear end of the car has a larger overturning moment and therefore a larger roll angle. Because of this, the RF tire gets more of the wieght transfer, and because front/rear percentages stay more or less equal in steady-state cornering, this unloads the LF tire and also increases the cross-wieght, which heats up the LR tire.
This agrees with the results I get when playing around with wieght transfer equations and such.

I haven't read the article, so I can't say for sure,  but I would bet the car was tight before.