IRL, when your car starts leaking fluids, you are very fast removed from the track. Safety reasons.
Right, of course. 
Unless the fuel is leaking inside the car… but how many laps do you think you make, beeing a genuine petrolhead? 
i was thinking to add 1 more category. the engine fuel consumption itself
i.e:
-light car
-small and light engine
-but consumes more fuel in favor of responsiveness
Vs
-heavier car
-bigger engine
-but is pushed to lower the fuel consumption for it’s size
these 2 cars might have similiar size fuel tank, which means similiar weight in fuel
then again. you could either push a F1 or MotoGP fuel rules.
F1 has a limit of the fuel allowed to be consumed by the engine per lap
MotoGP basicly limits the total amount of fuel on an entire race (20lt iirc)
both which might be easier to implement, but means lowering the amount of differentiation of the cars people will build.
also considering the open beta, which makes the engine a lot more prone to overheating. might make the overall race SSSLLLLLOOOOOWWWWWW (due to drag)
and a question
you said track humidity. will humidity affect the overall engine performance?
and will the track temperature effect the cooling?
With humidity I meant water on the track surface. No effects on the engine, just on grip.
Ha! Yes, yes I did! It was still heartbreaking to watch, however. 
Similar to Carlos Sainz, his WRC car broke down within viewing distance (300m) of the finishing line. He was, IIRC, in the lead at that time.
Edit, he was fourth, and needed that place to win the Championship.
[size=150]Challenge Submission Tool[/size]
Because of the new weather and pit stop system I need more information from the future challenge participants. In order to get that in a properly formatted way (which is always a problem with forum challenges), I built a little tool which will help you with setting up your entry and strategy:
abload.de/img/love2015-09-1919-00-40hsxs.png
[ul]]Player Name: pretty obvious/:m]
]Car Name: pretty obvious/:m]
]Select Trim: choose a trim from your trims folder. The linked engine family and variant and car model files are searched automatically./:m]
]Regular Stops: set up the number of planned pit stops/:m]
]at % of race: set up when to make the stop (can be % of time limit or % of lap limit)/:m]
]refuel: choose if the car should be refueled/:m]
]new Tyres: choose if you want new tyres/:m]
]at % tyre wear: choose at which tyre wear threshold the tyres should be replaced during an unplanned stop in case they wear out faster than expected/:m]
]at % damage: choose at which damage level the driver should head for an unplanned stop/:m]
]at % race time: choose when unplanned stops may be done. In this example, the driver won’t pit during the first and the last 15% of the race even if it starts raining, the tyres wear out or the car is heavily damaged./:m]
]replace regular stop within x% race time: if an unplanned stop is done x% race time before a planned stop, the planned stop will be cancelled and refueling and tyre changes are done immediately./:m]
]Compound changes: Set track humidity thresholds for when to change the tyre compound if the weather changes./:m]
]Preferred starting number: Choose your preferred starting number between 2 and 99. 1 is reserved for the previous champion./:m]
]Export submission: Write the strategy to a .lua file and write 4 lua files with the car data. Your only job is to zip all 5 files up and PM the zip file to me in the end./:m][/ul]
Please let me know if you have any questions or think I forgot something.
ooh i was thinking about this, how would we decide the constraints.
sooo we just pick the car trim, and the tools automatically gets and make all the .lua files needed right? we just zip the exported end result from the tool?
Nice!
[size=85](All that is missing is a hidden line: “If right behind car#, aim carefully and redline the engine”)[/size] 
Looks very cool! I imagine I’ll have to revise my pit strategy based on pre-season testing, but that should be fairly easy with a tool like that.
Mm, question: if the race strategy overestimates how far the car can get on its fuel load and it stops early (e.g. if I said “stop at 40%”, but at 35% the car is running out of gas), will that replace the scheduled pit stop the same way that a stop for tyres or damage would?
Yes, that would be the optimal case. Plus the estimated fuel consumption per lap should be updated then, because else the next pit stop would be too early, too.
Well, I’m not saying I would object if I could update the pit-strategy mid-race, but I’m guessing in that case the car would also end up taking fuel at 70% instead of 80% and barely making it across the finish line.
Ooh, a couple more ideas - these are probably super ambitious, but:
[ul]]Could cars delay leaving their pit boxes when other cars would be passing that point in the pit lane? I know that part of the pit strategy is to try to take a pit stop when other cars aren’t taking pit stops; that could add a small advantage to doing that./:m]
]Could I set up the car to take a pit stop early if it’s being held up by the car in front? So, basically, if it has n failed overtakes on the same car in a single lap (3 might be a good number?) and it’s within its planned pit window, it pits early in hopes to get some clear road and more speed./:m][/ul]
The first thing should be easy to do. The second thing is a bit more complex because of the way the AI works currently. We’ll see, it’s on my list, but probably not for the first races.
Cool - thanks muchly!
Mhh…the starting amount of fuel? So I can plan carefully the stops and if I want to refuel the car or not.
You just say when you want to pit and if the car will be refueled then. The neccessary amount of fuel until the next fuel stop or race finish is then automatically calculated from the comsumtion per lap which ia determined in training. I think this is the easiest way to go for forum challenges.
Ok, perfect.
Looks great Martin!
I am wondering if a feature of “never use intermediates” would make sense, i.e. a higher risk move in your strategy to either stay out longer and waiting for it to dry up (or the opposite) instead of coming in to change. Would be a “simple” checkbox in the GUI?
As a newcommer to this game I must say… This is epic!
Do we have any official word on racing in game?
I am looking forward to playing a sportier manufacturer when the campaign hits. So some very simple motorsport mechanic as a way to build reputation for the company would be great. The actual racing management should not be complicated since it is not the focus of game, but racing has been an important part of RL car companies and building and trying to build good but sometimes hard to sell homologation models to boost the image of the company sounds like fun stuff to me