"Mr. Toad" at Laguna Seca (23 January 2022)"Mr. Toad" at Laguna Seca (23 January 2022)
 Turn 4 |
 Packed and ready to leave in the morning |
 Also sprach Corkscrewstra |
 Swapping tires |
 20-mm spacer for stock wheels |
 McLaren gets a drink |
 Cleaning up fom a wreck |
 Not an ideal end to the day (the driver was ok) |
 Ready to head home |
This was my second full day at Laguna Seco on track-dedicated Nitto NT01 tires on a sunny and relatively warm day for January. I managed to shave over 2.5 seconds off my best lap time in November but still fell 1.682 seconds short of my personal best at Laguna Seca.
A tire pressure experiment probably
hindered lap times for the first few sessions; I finally reverted to my
normal pressures and lap times improved but then an accident curtailed
the day before I had a chance to improve further.
Best lap of the day
(1:53.190)
The day's best lap ended up being not only the last lap of session 4 but also the last lap of the day. Absent the early end to the day I'm confident that I would have trimmed my lap time further.
During my second time at Laguna Seca with this car I spent a lot of time figuring out where to shift, concluding that it was best to drive most of the track in 4th gear, downshifting to 3rd only for turn 2 through turn 4 and then again for turn 11. Notably, I decided NOT to downshift for turn 8 (The Corkscrew). Gravity provided most of the needed acceleration with just enough throttle to spin up the turbocharger. Doing so avoided squeezing in an upshift before turn 9.
Greg Epstein goes all the way down to 2nd gear for The Corkscrew in his MINI Cooper and he finally convinced me to try downshifting during the afternoon. It does feel a little better and now that I'm more comfortable with the car the quick upshift is tolerable.
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 morning 0905 62°F 28 28 28 28 after session 1 0946 60°F 35 36 33 32 after session 2 1104 66°F 36.5 36.5 32.5 32 after session 3 1256 69°F 35 34.5 32 32 304°F 310°F 372°F 354°F before session 4 1323 69°F 32 32 - - 34 34 - - reset after session 4 1416 64°F 38 38 32 32 306°F 323°F 399°F 360°F
I had been starting off with 31 PSI tire pressure on all four wheels, which led to relatively high pressures after warming up, especially for the front tires. Some times get quite slipery at high pressures but the Nitto NT01 tires I'm now using as dedicated track tires fare well at "excess" pressure.
Athough the NT01 tires handle high pressures adroitly, several friends said I should start with lower pressures so I finally caved and tried it. The car felt like it was wallowing during much of the first session and my lap times were slow during the morning sessions. I finally bumped up the pressure before the fourth session, after which the car handled better and I hit my best lap time of the day. Alas, a mid-afternoon crash of another car in turn 4 ended up cutting the day short so I didn't have a chance to explore how much more I could improve with higher tire pressures. (The driver got some medical attention but will be ok.)
 Missing center cap |
 Back wheels are intact |
In addition to pumping up tire pressure and cooking brakes, heat took a
toll on my new track wheels, causing the label caps to separate from the
front wheels.
Only four sessions on a cool day combined with modest lap times meant this was a relatively easy day on brakes, at least by the standards of Laguna Seca, and the temperature measurements later in the day reflected this view. It still was enough to finish off the brakes. The photographs below show a pair of cracked front brake pads; the rotors could have lasted another day but it made sense to install pads and rotors together. Fortunately, I had spares for both in my inventory.
Unfortunately, the seals in the calipers also gave out and were seeping brake fluid. It was time for their second rebuild since they were new less than a year earlier—I'm now planning to have them rebuilt after five track days. The brake shop did not have the necessary parts so it took nearly a week to have the calipers rebuilt.
 Cracked front brake pads |
 Front brake rotors |
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Copyright © 2022 Karl L. Swartz. All rights reserved. |
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