"Mr. Toad" at Sonoma (8 November 2021)"Mr. Toad" at Sonoma (8 November 2021)
 Exiting Turn 11 |
 |
 |
 Fancy times: we rented garage space! |
 With friends in the garage |
 Kissing MINIs |
 Swapping back to street tires |
 |
This was my second track day at Sonoma Raceway. The first was over 30 years earlier, driving a very different car in the form of my 1979 BMW 323i, so for all practical purposes this was my first time driving the track.
I had planned to go in mid-September but tire problems a few weeks earlier worried me, especcially on an unfamiliar track that has some rather tricky spots. A cracked brake rotor with sketchy availability of a spare was the last straw; I let someone else take my spot and got a refund. Instead, I drove up in my 1979 Volkswagen Cabriolet to hang out with friends who were driving, a day which instead of a fun lark turned into adversity.
Golden Gate Lotus Club also sought out volunteers to move from the (full) Intermediate group to the relatively empty Advanced group, and I offered to move up. With 58 previous track days I figured I could hold my own; learning a new track and wrestling tire worries should have given me pause.
Before tackling a new track, I study lines on the track via Race Optimal's modeling, videos, and discussions with drivers whom I trust. I had done some of that before the balk two months earlier but those lessons had faded and for various reasons I wasn't able to brush up as I would have liked before this day. That, too, was a setup for disappointment.
 Best lap of the morning (2:19.431) |
 Best lap of the day (2:18.365) |
My best lap of the morning, during the second session, yielded a sluggish 2:19.431 lap time. Some of this was due to being the slowest car/driver in the group, which meant many slowdowns as I allowed faster drivers to pass, but I also fought what I thought were tire problems despite this being my first full day with new track wheels and tires which should have been wonderfully sticky.
By the late-afternoon sessions I had sorted out some of the issues and gained familiarity with the track, which netted an improvement of over one second on my lap time—still poor but I was gaining confidence.
At several places I thought my tires were yet again failing me. The worst was the exit of turn 2, which felt like a washboard, trigering wheel-hop which I thought had been tamed a year earlier with a Damond Motorsports rear motor mount (RMM) and which led me to back off on the throttle running up to turn 3. To a lesser degree, the same problem occurred running through turns 9 and 10.
It was mid-afternoon, when someone passing me led to a tight line through turn 2, that I realized that the problem was poor track surface rather than my new tires. Taking a tight line through that turn, with a late apex and avoiding the rough pavement at the exit, allowed me to build more speed leading to turn 3.
That it took so long to figure this out was a stupid mistake on my part, but several days of awful tires had led me to no trust my own equipment. Add in a new and somewhat-intimidating track and it was an easy error.
This was the second time using my new Nitto NT01 track tires and wheels, and the first full day with them. The following table summarizes tire pressures throughout the day, in PSI, along with front-brake temperatures, as measured with an infrared pyrometer after each session:
rotor caliper Description Time Ambient LF RF RR LR LF RF LF RF before session 1 0808 44°F 31 31 31 31 reset after session 1 0841 52°F 36 36 34 34 after session 2 0938 53°F 35 36 34 34 mid session 3 1028 58°F 35 34 32 33 after session 3 1042 59°F 36 36 33 34.5 202°F 240°F 183°F 192°F after session 4 1143 63°F 37.5 37 36 36.5 before session 5 1312 63°F 32.5 32 32 31 after session 5 1342 64°F 36.5 36 34 33.5 279°F 268°F 196°F 195°F after session 6 1443 62°F 36.5 36 34 34 239°F 250°F 188°F 200°F after session 7 1542 60°F 35.5 35.5 34 32.5 266°F 280°F 199°F 211°F
The pressure check in the middle of session 3 was because something felt strange after several laps. Tire pressures were reasonable, though, and this was likely just one manifestation of the fake tire problems that haunted the first part of the day.
Given my leisurely pace during the day, neither tire heat (with
associated pressure increases) nor brake heat were a problem.
The tires still picked up plenty of rubber from the track,
especially the rear tires.
|
Copyright © 2021-2022 Karl L. Swartz. All rights reserved. |
|
_with_emphasis_on_Long_track.svg){kind=link}