2:13

Описание: This was the first session of the second day. I ran a 2 :13.98 first session on the first day, but unfortunately did not put my camera in the car. The afternoon sessions were too hot to back it up, so I went back out the second day first session while it was still cool and laid down a 2 :13.91 on the fourth lap.

I've been slowly tweaking the car's setup with alignment, brakes, tires, etc, and have gotten it fairly sorted. The last piece is getting the rear more planted, as it oversteers almost anywhere you try to push it. Stock, the 720S is quite under-steery, especially with the factory 245 tires, but nothing an alignment and some 265s couldn't fix. Now the rear is very loose, even on 325 Hoosiers with 3* of camber and positive toe. Once that is sorted, I think the car can gain another second.

I did a couple warmup laps to get the tires up to temp while trying not to slip them too much during warm up, then sent it on the 4th lap for the 2 :13 (starting around 5:25. Around turn 9, I felt the car cutting some power, and I realized I forgot to hit the ESC button to enable "dynamic ESC", which essentially turns off the nannies, and prevents the car from cutting power on wheel speed differentials. You can see my trying to push this after navigating past turn 10 at full tilt coming into 11 at 150mph.

You can also see that I run my heater at 100% to try and help keep things cool. Generally the first major issue I have is the clutch will overheat as the coolant temp gets hot, and it will kick you out of gear. This is a big reason I run at stock power level, despite having a tune capable of much more power available. I will be swapping the water pump soon to see if it helps, as I had this issue years ago and a water pump seemed to fix it for a while.

I also am getting more frequent suspension failure messages, so I believe the accumulators are also going bad. This may also help explain why the rear is so loose, because the 720S entire suspension setup is based on hydraulic pressure, and it actually uses this to replace the traditional anti-roll bar.

Engineering Explained actually has a really cool video on the 720S's hydraulic suspension system here:
   • The McLaren 720S Suspension Is A Complex M...  

To top it all off, my rear right e-brake broke after this session, as a friend pointed out a weird noise in the rear right. The caliper was only held on by the rotor and the wire connected to the brake. I ended up removing both rear e-brakes to run the last two sessions.

There's some really cool footage from the event outside the car here:
   • Super Lap Battle LIVE! Circuit of the Amer...  

Overall, it was an awesome weekend, and had an absolute blast!