We were comparing F1 to sportscars.

The fasted trap speed of a F1car was the (1999) record for F1 is 361.8 km/h = 100.5 m/s by David Coulthard at Monza.

The highest speed recorded in an European race was at Le Mans:

The record for top speed in a closed circuit held by a WM at Le Mans (when Les Hunaudieres was still a 5 km long straight). at about 405-407 Km/h (sources differ on the exact speed).

 

IRL is a very different story at the cars are specifically built to run long distances at full speed.