"Mr. Toad" at Buttonwillow (14 February 2021)"Mr. Toad" at Buttonwillow (14 February 2021)
 Ready to roll |
 Collect $200? |
 Bus Stop under dramatic skies |
 Saturday sunset |
 Resting up |
 Sunday sunrise |
 |
 |
| Greg's 2014 MINI Cooper S (F56) | |
 1985 BMW 735i (E23)— U.S. with Euro details |
 |
 |
| Ford Mustang race car | |
 California Track OK sticker |
 BMW 735i (E23) |
 Series license that almost says VOODOO |
 Ready to pack up |
 Sunset at the track |
This was my first time at Buttonwillow so the first session was spent learning the course. My lap time in the second session was nearly five seconds better, then subsequent sessions continued to improve by about two seconds each time, with my best lap in the last session at 2:20.693.
One feature of the track is multiple blind turns which occur at the crest of a hill: a right turn following Cotton Corners and Phil Hill. These kinds of turns are intimidating at first but become quite fun once you figure out what lies beyond and tune the blind approach.
(Note: Hover over any turn name in the text to
highlight it on the map.)
 Best lap (2:20.693) |
 Fastest speed (106.2 mph) |
One weak spot was the left kink at the end of Bus Stop. It looks like a really sharp turn but can be driven much faster than it seems. Following Greg Epstein and his 2014 MINI Cooper S during the last session really helped drive home just how much I was giving up on this corner.
Greg also helped after the first session by observing that the best line through Cotton Corners was to go deep into the first turn, which allows a better line through the left turn and a good setup for the cresting right turn which follows.
Sweeper is a carousel leading into the Esses. I always struggle with carousels as there isn't a clear apex. In this case, it ends with a sharp right, a crucial turn since the Esses can be taken at full throttle which then leads into the fastest (for me) straight. A miss going into that stretch exacts a huge penalty. By the end of the day, I was reasonably comfortable with Sweeper and its exit.
I used 3rd gear for Off Ramp, shifting back to 4th gear at the exit and staying there for all the rest of the track. I briefly experimented with staying in 4th even through Off Ramp but engine speed dropped to about 2,500 rpm and Mazdaspeed 3 engines are known for bending connecting rods at full throttle below 3,000 rpm due to the torque generated once the turbocharger spools up. The lower gear probably provided a slightly faster run through the latter part of the turn, albeit at the cost of a shift at the exit.
The only upgrade before this track day was a stiffer rear adjustable anti-sway bar (RSB), intended to curtail the worst of the car's tendency to understeer. As this was my first time on this track I had no baseline for comparison (Laguna Seca in late March will be the acid test) but didn't experience any understeer.
 Heat cracking on right front rotor |
 Split right front inner pad |
 Uneven wear on right front outer pad |
I installed a fresh set of G-LOC R16 front brake pads along with Motul RBF 660 brake fluid before Laguna Seca last November and had hoped that they would hold up for this track day. Alas, I felt the all-too-familiar brake fade at the start of a mid-day session and by the end of the day the right front wheel was making ugly metal-on-metal sounds. The nasty sound was due to a cracked and charred inner pad, as seen above. The outer pad held up but wear was uneven.
Both front rotors had been suffering heat cracking but they held up
until their retirement after this day, replaced with much bigger rotors
as part of a StopTech Big Brake Kit (BBK).
Tire pressures are always a challenge since I typically see an incease of 7-10 PSI in the front tires during a session. Starting a session with tire pressures that are too low requires a few laps just to warm up the tires—with TPMS (Tire Pressure Monitoring System) flashing warnings—and often results in horrible rollover and sidewall wear as seen at right. Starting with pressure too high results in the car feeling like it is on ice skates.
The following table summarizes tire pressures throughout the day:
Description Time Ambient LF RF RR LR Note initial 0815 40°F 36 36 35 35 30 30 30 30 reset after session 1 0905 50°F 37.5 38 35.5 35.5 34 34 34 34 reset before session 2 1015 50°F 29 31 32 30 sun on right after session 2 1100 57°F 36 36.5 35 35 before session 3 1229 66°F 29 31.5 33 31 sun on right; almost two laps to stop TPMS after session 3 1305 62°F 36 36 35 35 before session 4 1452 62°F 30 30 32 31.5 hazy sun on left after session 4 1526 64°F 36 36 36 34.5 before session 5 1614 64°F 31.5 30 31.5 32 hazy sun on left after session 5 1645 62°F 35 35 34.5 34 Chevron 1833 57°F 32 31 32.5 32 35 35 34 34 reset
The Golden Gate Lotus Club usually has three run groups (though for the recent
Thunderhill 5-mile day
they had just two). This means the dwell time between my sessions
is 40 minutes, except for lunch.
OnGrid used five groups, and with more participants uses up to seven groups.
This meant the tires cooled for over an hour each time, leading to low tire
pressure at the start of every session. After the first session I ended up
with the left front tire being low enough to trigger TPMS complaints; by
afternoon I patched this problem by parking the car so sun warmed the left
side a little.
This video (MPEG-4 version) is from session 5 and features my best lap, following Greg Epstein in his 2014 MINI Cooper S. He's a relative newbie on the track but taught me a few things. In particular, following him showed me how much faster I could take Bus Stop.
This video (MPEG-4 version) is from session 4. I was working on knocking a few seconds off my lap time when a Honda Fit passed me. The driver was either really good or really crazy ... or both! I learned a few tricks from following him, but was also wary and kept some distance after he started to spin (but recovered) several times.
(Apparently Kendall Barr was driving the Fit; modifications include a stereo.)
|
Copyright © 2020-2021 Karl L. Swartz. All rights reserved. |
|
