I was running on the wrong tire pressure.
Way too low and the tires overheated after lap 1 which made me slow.
I turned a lap 3 seconds slower than in practice session.
After I lost track to the other TR4s I saved the engine and and did slow 3:11-3:14 laps.
I have not much practice on that track. This was the 2nd time I raced there but it was okay.
Endurance racing is not that exhausting as a sprint race so I felt well after the race.
In early September, when Kas is in Germany, we do the 3 hour race on the Nordschleife.....I think that will be exhausting. 2 pitstops for refueling.
Cheers
Chris