Barber Motorsports Park — August 15–16, 2026
A 1:42.70 on Saturday, and on Sunday the corners got faster while the lap did not.
Saturday, lap 22, run 2. Beat the old Barber PB of 1:43.910 by 1.21 s. May's M440i best was 1:45.99.
Lap 13, run 1, in the cool 77 °F morning. 0.69 s off Saturday's PB — and still 0.52 s under the old mark.
Both days' clean laps stitched — 2.00 s under the PB, from 15 contributing laps. Sunday owns 6 of the 15 corner windows.
51 Saturday + 22 Sunday timed laps; 50 clean (35 / 15). Tires 13 heat cycles in, ~21 out (estimated).
The weekend
Two-day HPDE weekend, instructing Taylor in the right seat. Saturday: 51 laps over six runs, a 1:42.70 personal best on lap 22 that beat the old mark by 1.21 s, plus a confirmed fuel-starvation limp and the tire-pressure lesson that reset the hot targets to 34F/32R. Sunday: a short, cool two-run morning — 22 timed laps, done by 10:09 — best 1:43.39. The lap time did not fall, but the corner work did land: six of the fifteen corners posted their fastest window of the weekend on Sunday, and the brake-release rebuild at Charlotte's Web raised the floor as well as the ceiling. Stitch both days' best segments together and the lap is a 1:40.70 from fifteen different laps — the remaining time at Barber is repeatability, not pace.
Briefs
Written before the first session. Minimum speed, not later braking; target 1:43.910.
Rebuilt between sessions after the 1:42.70. Carries the pressure diagnosis and the first corner deltas.
Built overnight from all 51 Saturday laps plus the May baseline and a coaching corpus. Fifteen corner cards, three-model reviewed.
The definitive weekend review: what the plan bought and what it did not, all fifteen corners ranked by remaining time across both days, the ranked next-time list, what transfers to Ozark and AMP, and the lessons banked.
Runs
| Day | Run | Local | Laps | Best | Amb °F |
|---|---|---|---|---|---|
| Sat 08-15 | R1 | 08:00–08:44 | 14 | 1:44.79 | 77.2 |
| Sat 08-15 | R2 | 09:42–10:18 | 12 | 1:42.70 ★ | 85.6 |
| Sat 08-15 | R3 | 11:27–11:41 | 8 | 1:44.59 | 91.9 |
| Sat 08-15 | R4 | 13:18–13:45 | 8 | 1:45.13 | 94.5 |
| Sat 08-15 | R5 | 14:44–14:52 | 4 | 1:45.81 | 94.5 |
| Sat 08-15 | R6 | 16:01–16:08 | 4 | 1:43.34 | 94.5 |
| Sun 08-16 | R1 | 07:58–08:39 | 16 | 1:43.39 | 76.6 |
| Sun 08-16 | R2 | 09:51–10:09 | 6 | 1:43.41 | 88 |
- 08-15 R1 — Started 30/29 psi cold — grew to 40/39 hot and went loose. Pitted, bled to 32/30 hot; the next lap was the run's best.
- 08-15 R2 — The personal best. Also the run that produced the fuel-starvation limp — laps 19–21 came back power-capped, down to 103–105 mph top speed against 114–117.
- 08-15 R4 — Hottest part of the day, heaviest traffic. Slowest run of the weekend.
- 08-15 R6 — Second-fastest run of the weekend, at the end of the hottest day on the oldest rubber. The single cleanest piece of evidence that the tires were not falling off.
- 08-16 R1 — The "go early" plan, executed. Coolest track of the weekend and it did produce the day's best lap — three laps under 1:44 in this run alone.
- 08-16 R2 — Last run of the weekend. Lap 23's 1:43.41 was the final lap logged — the data logger stopped at 3158 m, so it has a lap time but no complete corner trace.
Sessions
- Best
- 1:42.70
- Median (clean)
- 1:46.48
- Laps timed
- 50
- Clean laps
- 35
- Telemetry rows
- 147,272
- Best
- 1:43.39
- Median (clean)
- 1:46.89
- Laps timed
- 22
- Clean laps
- 15
- Telemetry rows
- 66,388
Tires
Bridgestone Potenza RE-71RZ (2026 set)
265/35R19 front · 275/35R19 rear · treadwear 200
13 HC → ~21 est.
Estimated — no tire day logged for these dates yet.
13 heat cycles entering the weekend (VIR 6/28 4, 6/29 4, Barber 7/12 5). No tire_day row exists yet for 8/15 or 8/16, so the exit figure is an estimate: 6 cooldown-bounded blocks Saturday + 2 Sunday = ~21 under the v2 heat-cycle rule. Needs a logging pass to become fact.
Hot targets settled at 34 psi front / 32 psi rear after Saturday's first run. Held both days.
None detected. Saturday's 16:01 run was the day's second-fastest; Sunday's peak lateral g (1.32) was higher than Saturday's (1.30) on older rubber. No progressive within-run mid-corner speed loss in the fast right-handers on either day.
Weather
Sat 08-15 · 77.2–94.5 °F
Dry. Climbed all day: 77 °F at 08:00, 86 °F by mid-morning, 92–95 °F from noon on.
Sun 08-16 · 76.6–88 °F
Dry. 77 °F for the morning run, 88 °F by the second. The weekend ended before the heat did.
silver.lap.source_extras.ambient_temp_c, per run. The companion weather_condition field is an unmapped LapTimer integer code (2→4 Saturday, 1 Sunday) and is not interpreted here.
What the weekend taught
Fill before every session
The G29's saddle tank has one delivery module and a flow-driven jet pump on the passive side. Sustained lateral load plus the light crest at T4 empties the collector, transfer stops, rail pressure sags, and the DME latches a reduced-power map until an ignition cycle. It happened at only ~6 gallons under full — about 56 % of the tank — so the street folklore about a quarter tank is wrong for track use. Topping off between every session is free and it is the entire fix; Sunday had zero recurrence.
Hot pressures, not cold pressures
30/29 cold in August grew to 40/39 hot and the car went loose. Bleeding to 32/30 hot fixed it inside one lap. The target that held for the rest of the weekend: 34 psi front, rear two under, measured hot, bled after every session as ambient climbs. The tell for over-pressure is mid-corner speed loss in the fast right-handers — not peak lateral g, which stays flat and will lie to you.
"Patience" was the wrong cue
At Charlotte's Web the slow attempts were the patient ones: braking earlier, 0.4 g softer, fully off the pedal 31 m before the apex, back on the throttle 22 m early. The rebuild cue — brake later and to a genuine threshold, then bleed the release through turn-in — produced Sunday's fastest T5 of the weekend and, more usefully, lifted the floor: Sunday's six worst attempts still braked to −0.83 g where Saturday's worst six managed only −0.60 g. Throttle pickup also moved from 0.5 m before the apex to 5.5 m past it.
The tires were never the limit
Entering at 13 heat cycles with falloff expected past 15, the plan was to take the shot early. In fact Saturday's 16:01 run was the day's second-fastest and Sunday's peak lateral g was the highest of the weekend. Nothing in two days of data supports a heat-cycle ceiling on this set yet.
The remaining lap is repeatability, not speed
Every one of the fifteen corners now has a weekend best that beats the May M440i template — the template no longer binds anywhere. The whole-weekend stitch is a 1:40.70 from fifteen different laps, 2.00 s under the PB, while the sum of per-corner spread grew from 3.68 s Saturday to 4.81 s Sunday. There is no new speed to find at Barber right now; there is a consistent lap to assemble.
One assignment per session beats five
T1 got a single narrow one-sentence ask and produced the weekend's best T1. The Carousel was item 1 of a five-item list in a 16-lap run and went backwards on both its best and its median. The corner that got sole attention improved; the corner that competed for attention did not.
Next time at Barber Motorsports Park
- T2/T3 — 0.87 s. One fixed visual turn-in marker, the same one every lap. The two line families are only ~0.09 s apart, so the 0.49 s of scatter is turn-in timing, not line choice. Biggest self-spread on the circuit and the biggest single loss to the M3 (+0.752 s).
- T5 Charlotte's Web — 0.62 s. Keep the cue word for word: brake later, to a genuine threshold, then bleed the release through turn-in. Aim the minimum at 44–45 mph, not 40. The only technique change of the weekend that measurably moved a corner.
- T1 — 0.57 s. Carry the minimum; 78 mph is proven against a 71.2 median and the M3's 76.4. Do not re-litigate the brake point.
- T12 — 0.51 s. Stop over-slowing the compression — the M3 carries 72.9 mph minimum to Bill's 64.1, the largest minimum-speed deficit on the lap, and over-slowing costs twice on the 8.2 % climb out. Regressed on both best and median Sunday.
- T13/T14 Carousel — 0.44 s. One sustained 82–83 mph arc, no mid-corner bleed — and make it the first session's sole assignment. Largest single-day spread on the circuit, on-camber (+3.3 %) support Bill is not using, and the one thing the Sunday plan did not buy.
- Structural: run more clean laps before chasing the number. Fifteen clean laps is not enough attempts at a lap that needs six corners to coincide; Saturday needed 41 to produce one 1:42.7.
- Log the tire day at the event. The heat-cycle count for this weekend is an estimate because no tire_day row was written trackside.