May I ask what temps your supercharged cars are running at?

This week, I decided to monitor the live data for grins using Torque and my bt OBD unit. Outside air temps were low...in the 60s, and at highway speeds, the temp was 199, however at idle, it rose to 204. My xk8 NEVER goes higher than 200 even in the summer here in Texas. Is this temp range that i am seeing normal?

 

It's probably normal, after all, 204F is still under 212F, the boiling point of water at atmospheric pressure at sea level. Cars need to run close to the boiling point for efficiency, hence the coolant pressure cap to even allow temps to go beyond 212F. Main thing is to wait for a hot Texas day and see what the car gets up to at idle. BTW the antifreeze in the water does raise the boiling point as well as lowering the freezing point, so you are probably pretty safe.

 

Those temps are perfectly normal for any engine. I can't cite the Jag ECM programming, but Cadillac (and most all GM) electric radiator fans don't kick on on to low speed until 225 F, high speed fan at 235 F.

Center gauge position is 190-220 F, "hot" is 262 F.

The x350 temp gauges are similarly damped, though of course not exactly the same gauge readings as above. Unless your engine is going over 220 F I would not worry at all.

 

@Matt

I recently had the stupid magnetic float sensor in the stupid plastic header tank fail so I had "Engine Coolant Low" constantly on the information center. I know the temp gauge is damped (The reason the realgauge exists) so I was using the Torque app to monitor my real engine coolant temperature until I replaced the old stupid plastic tank with a new stupid plastic tank.

Here in CA, outside temps in the 70s, my temp fluctuated between 193 and 195. Didn't really matter too much if I was driving or stopped idling

 

Interesting, although not in dire jeopardy it seems, I'll still undertake a t-stat change and flush. I also like to use filtered water as well to keep as many minerals out of system as possible.