24 Hours of Le Mans

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I've been putting off running the 24 hour endurance races for a long time, but after running hundreds of laps in WRS week 31 I felt there was probably never going to be a better time to get it done. I'm currently 15 hours into the race and it's getting harder and harder to find the motivation to sit down at the wheel to get laps in. Perhaps writing a log of sorts here will help with that. :)

First things first, before I started off I did a little investigation into my opposition to see what I was up against. Preparation is key, after all. :sly: I started a race and parked my car by the side of the road, then I went out for a run while the AI duked it out among themselves. :dopey:

Watching the replay revealed the following information about the different AI cars:

C60 Hybride: 9 lap stints, 3'31.6 fastest lap/3'48 pit-in lap, refuel 90l
Audi R8 '01: 10 laps, 3'31.8/3'42, 92l
Bentley: 11 laps, 3'34.4/3'46, 95l
Audi R8 '05: 10 laps 3'33.4/3'44, 93l

These 4 seemed like my main competition, the rest of the field where significantly slower. The '01 R8 had by far the best lap times and pit strategy and quickly pulled a substantial lead. The C60 Hybride suffers from big fuel consumption and also seriously overworks the rear tires which show in the pit-in laptime. Bentley is king of tire wear/fuel economy.

The only premium car in the field was also the car I was considering using and it did the following:

Audi R10 '06: 11 laps, 3'41.5/4'08, ~90l

I wanted a "realistic" race where I don't blow the field out of the water, so I'm going to use a stock car with racing mediums just like the AI. I also wanted to drive a modern LMP which quickly narrowed my choices down to the R10 or the 908. I decided to start some tests with the R10 because I like how it looks and I've read the 908 has poor headlights :nervous:.

The first few rounds with a fresh oil change quickly revealed that the car was more than capable to match lap times with the competition. With my regular hot-lap setup I was able to comfortably do 3'28-3'29s on fresh tires and I could do 7 laps at a reasonable pace before the tires started to fall apart on lap 8. Typically lap 8 would be about 3'45 with pit-in. I tried 9 laps but never got past the porsche curves before the tires gave out completely and I started spinning at every turn.

The only problem was that this setup was very prone to oversteer and as the tires wore it got almost ridiculous under throttle, so I tried to tune it out as much as I could. Doing the exact opposite of what I usually do when I tune for fast lap times, I managed to get rid of almost all oversteer and extend the life of the rear tires quite a bit. I lost about 1 second per lap at the start, but I could now do 10 laps and the car was much easier to drive on bad tires. Based on my lap times and how the car felt I settled on using 9 lap stints for the race. My fastest/pit-in laps where now ~3'29/3'40 and I would take on 65l of fuel per stop. Go diesel! 👍

At this point I decided to take the 908 out for a spin to see how it compared. On my first lap I did 3'23 so it was obviously too quick to have a good race. I also managed to go 11 laps without stopping so it was really just better than the R10 in every way, so back in the garage you go!

Time for me to do another stint at the wheel! I'll do a write-up of the first part of the race next.
 
Time to Race. Weather was sunny with a few clouds and the big guys from practice where all lined up. From the Audi team, Nurminen and Landi in the '01 and '05 R8s and from Pescarolo, Kovacs and Furst in the C60 Hybride and the Courage C60. There where also a few closed cockpit cars on the track: Bentley Speed 8 (Burch), Toyota GT-ONE (Jarvinen) and Mercedes CLK-LM (Estes). The BMW V12 LMR (Friedrich) and a couple of GT cars filled out the grid (McLaren F1, Nissan R390, Dodge Viper) but my R10 team-mate was nowhere to be found... Towards the end of practice I had also decided I would use Traction Control at 3 and a quite front-biased brake setting in order to conserve rear tires even further. With these settings I lost another 1 second per lap at race pace but I felt it was worth it for the feeling of safety on worn tires. I could always adjust it on the fly later if I changed my mind! :dunce:

I mentioned before that I wanted to keep the race realistic, and that includes always trying to drive clean. No cutting corners, no going off track if I can avoid it and definitely avoid any contact with other cars. My goal was to finish without any incidents that would've ended the race if it was real life.

Before I knew it we had a green flag and the race was under way. Just as in practice I was able to easily slip past 3-4 cars going into the first corner and line up behind the leaders through Dunlop chicane. I could see up ahead that Nurminen had already jumped into the lead and I figured if I could get on his bumber quickly I could draft him down Mulsanne without worrying about cars closing in from behind. I managed to sneak past a few more opponents through the Esses and just caught his draft coming out of Tertre Rouge. As I watched my speed keep climbing far beyond what I could reach on my own, I made a quick decision to not pass the R8 but instead stay behind him and use his draft to conserve fuel and tires. This was something I had experimented a bit with in practice but never tried it for a full pit cycle. I knew he could run nearly my lap times so I probably wouldn't be able to pull away. With my superior fuel efficiency I would have a much shorter pit stop and then I could go solo from there. :sly:

So that's what I did! For the next 9.5 laps I shadowed the R8 '01, staying just close enough to use his draft but never making a move to pass. This is actually not as easy as it sounds, because there is a huge flaw in the AI that causes him to drop the throttle to about 50% whenever you get close enough to "make a move" in a corner. It's quite ridiculous to be honest; I can follow the car lap after lap and he will always take a certain corner at 115 km/h - but if I get within about 2 cars lengths he suddenly drops below 90 and unless I either pass or back waaaay off, he won't get back on the throttle until we're completely clear of the corner. This also makes it very hard to manage my stated goal of no contact when the car infront of you can suddenly drop his speed in the middle of a corner when you're expecting him to go full power. This behaviour is the biggest reason it's impossible to have tight races with the AI in my opinion, as soon as you push just a little they pull over and let you pass.

Anyway, enough whining about the poor programming at PD. I was able to "manage" the AI behaviour pretty well over the first stint and only suffered two or three "slowdowns". On lap 10 Nurminen decided to pit and I automatically followed him in. It wasn't until the computer took over control that I realized I still had a lot of life left in my tires, and I could only refuel 62l. I probably should've stayed out at least another lap :). I put in 32l of fuel to get a total of 70l and a good lead out of the pits, but I immediately regretted not putting in more since I would now be forced to pit in 9 laps and would've liked to have the option of going 10... Too late now though, and after my crew was done I got back out on the track in 2nd place after the Bentley (11 lap stints remember). After Burch had his pit stop I was alone in the lead with about 40 seconds down to the first R8 due to my very quick first stop. Not much else happened the rest of the first hour, there was no traffic and I just focused on putting in clean laps and I even extended my lead slightly over Nurminen.

Hour 1: 45s lead, followed by R8 '01 - C60 Hybride - R8 '05 - Bentley.
 
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With the first hour completed I was feeling pretty good. My fresh oil had started wearing off since lap 15 so my laps were slowing down a little, but no more than a second or two. I had set a best time on lap 12 of 3'28.996, which was slightly faster than I did in practice with TC on, and now it looked like it would be quite hard to beat that time with dirty oil. I decided not to push for fastest laps but work on consistency and hitting my lines. I was getting 3'31-32 on fresh tires and 3'42-43 on my in-laps so I was basically matching Nurminen lap for lap, with the difference being my quicker pit stops. At my third stop I paused the game to end my first session.

Next session was far from optimal - I was tired from work, sun was shining into the living room and I hadn't eaten yet. My out-lap was very slow as I was trying to get back into things and at the start of the second lap I started to push a little. This quickly turned out to be a bad decision as I went wide coming into the Esses and overcompensated and ended up wide on the other side on the exit and put two wheels in the grass. This put the car sideways and as I started moving back across the track to the right side all I could think was "don't cook the tires!" when obviously I should've been thinking "don't crash!" - so I banged the side of the car into the right wall. :banghead: This was probably a race-ending crash had it been a real race, so the question now was do I quit and try again or take a mulligan and keep going. 2 hours isn't that much time, but then again the circumstances weren't exactly optimal and after all it's not like I had a head-on collision, I just banged the right side a bit. The more I thought about it the more I convinced myself it was only fair to keep going, so I did. ;)

I had now started running into lapped traffic and passing the AI is always a bit scary. Just before 2 hours I passed a car on the outside through Porsche curves and he suddenly swerved right and squeezed me off the track onto the grass. I was able to get back on the track with only a light scrape against the wall so I figured this time my pit crew could just get a hammer to fix the bodywork next time around. I kept going but was really not happy with being off 2 times already, it was the last time I tried to pass the AI in that section though. :rolleyes:

Hour 2: Lead by 1'38, R8 '01 - C60 Hybride - R8 '05 - Bentley

As I kept going things seemed to settle down a bit. I was doing consistent 9-lap runs, usually starting out with two or three 3'32 then slowing a second per lap. Whenever I had to pass a lapped car I would lose 1-2 seconds as I was very careful not to pass in a place where the AI could decide to bump me off the track. My lead would fluctuate as Nurminen and I were now completely out of sync with our pit-stops. The same seemed to happen with the cars behind him as they all had different pit cycles. Not much else happened in the third hour of the race except that the sun was getting quite low and causing a bit of difficulty to see when driving back from Mulsanne corner.

Hour 3: Lead by 1'17, R8 '01 - R8 '05 - C60 Hybride - Bentley

After a pit stop I ended up on the bumper on Kovacs in the Hybride. Since he can lap just as fast, if not faster than the R8, I figured I'd try my tactic of drafting him around the track without passing. This was where I ran into the next PD programming wonder, the lapped AI behaviour! As it turns out, mr Kovacs would quite literally run himself off the track in his efforts to give me a clear path to pass him. It didn't matter if I made any indication that I was trying to pass, as soon as I was in his rear view mirror he would swerve back and forth across the track, slow to a crawl in the corners and outright refuse to go full throttle on the straights. It didn't matter if I stayed far enough back to almost lose his draft, and when we crossed the line in about 3'42 on a set of fresh tires I decided this wasn't going to work and passed him. Of course as soon as I did that, his AI went back to normal and his 900-something horsepower roared as he went right back in front of me. :rolleyes: We kept this up for a whole lap and in my frustration I lost focus towards the end of Mulsanne and missed my braking spot and went wide into the sand. I got back on track but lost at least 15 seconds against Nurminen, third time off track and not even a quarter of the race done... :ouch:

Eventually I caught back up with Kovacs and in some twisty parts I was able to pass and put enough distance between us to keep him from drafting me. I resigned myself to running by myself for the remaining 20 hours...

Hour 4: Lead 2'45, R8 '01 - C60 Hybride - Bentley - R8 '05
 
I've had a hectic week with work and life, but I finished the race over last weekend so updates to the report are coming! It won't all be as detailed as the first few hours but there was enough happening over the race for a few more paragraphs at least. :)
 

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