After watching the Le Mans last weekend I am really looking forward to do a proper endurance race again in a few weeks time when I have some more time. Biggest issue is to find your constant lap time and to match that to the AI to some extent.
Love me some endurance racing, always looking for an excuse to do it. I might do a just-for-fun 3-4 hour deal in something slow and silly after the Ring ends next Sunday morning.
I'm not sure how much endurance racing you do, just a reminder that it still always really comes down to challenging yourself, basically. You can do a bunch of test sessions with the AI to get a good feel for the pace and hopefully stint length of the cars you're trying to compete with(and I always recommend doing that), but until you've run the same endurance race a time or two you really can't be sure what's going to happen. Whether it's pCARS, rFactor, Gran Turismo, any game I've tried... something always pops up you weren't expecting, be it AI pace, your pace, damage, weather, pit strategies, fatigue setting in late, whatever.
That's half the fun of endurance simracing, but it also means you can't take it
too seriously or you may lose sight of the fun factor. However perfectly I get it balanced beforehand... sometimes I'm in a great class battle, sometimes I'm making a higher class look stupid, sometimes I'm desperately trying to chase down a slower class leader(or the last running car

) with a few minutes to go in the race.
One thing I'd recommend for anybody that doesn't already use it is this app from the PC2 forum:
http://forum.projectcarsgame.com/showthread.php?56777-quot-Custom-Random-Weather-Automator-quot
Apparently it was originally designed for PS4, I use it on PC(don't think it works for Xbox sadly) and it spices your race weekends up beautifully. There is another more elegant solution in the works for trying to get truly real-world weather but that's a lot more complex. This one temporarily takes over your control input which is a little creepy at first, but it's a simple deal as long as you don't start it in the wrong place. You tell it what percentages of weather you want and what types you absolutely don't want and then how many clicks to get down to the "save and continue" button and then look away while it sets up believable weather that you can't see coming beyond the first slot. I just wish you could have more than 4 slots for really long races.
Another recommendation is to consider turning off penalties. You know if you're breaking the rules and if it bothers you, then don't do it or self-penalize when you accidentally do. Getting disqualified 4 hours into a race for unintentional corner cuts that slowed you down(or for idiot bots doing idiot bot things) sucks. If you use Bob you have to worry about him getting DQ'ed too. I have only run a couple enduros in pC2 so far, but both of those things were big issues in pC1(as was Bob running out of gas, I hope they've fixed that... he was okay the one time I used him). I'd like to think pC2 is better about those things, but I'm leery of finding out the hard way.