🏁 West Coast & Southwest · Willows, CA
Thunderhill Raceway Park (3-Mile East)
Wide Technical High-Speed Asphalt
🔊 SOUND LIMIT: 103 dB at 50ft (Standard Club Limit)
🔄 ROTATION: Counter-Clockwise
🛑 BRAKING SEVERITY: 7.5 / 10
⏱️ Log Stint at this CircuitLENGTH:3.00 mi
TURNS:15 Corners
ELEVATION:75 ft
ROTATION:Counter-Clockwise
GPS COORD:39.54°, -122.33°
🌦️
Green Flag Track Weather & Tire Pressure Advisory
Live circuit meteorology (Open-Meteo), interactive Doppler radar, and educational thermal rise advisory for North American circuits.
📍 Willows, CA·15 Turns·75 ft Elev
🟢 Green Flag (Dry Track)Elevation: 75 ft · Coordinates: 39.5392° N, 122.3317° W
Thunderhill Raceway Park (3-Mile East)
📍 Willows, CA · Clear & Sunny · Surface: Wide Technical High-Speed Asphalt
📡 Observation Time
Live
Syncing...
Ambient TempAir
...
Feels like 78°F
Est. Track SurfaceAsphalt
...
+22°F Solar Delta
Density AltitudeAir Density
...
-4.2% HP · Elev: 75 ft
Wind & HeadingCompass
...
Heading 45° (NE)
Humidity & BaroAtmosphere
...
1013 hPa Barometer
Est. Thermal RiseCold → Hot
...
Cold-to-Hot Expansion
Track Grip WindowFriction
...
200TW & Slick Sweet Spot
Precip RiskNext 4h
...
Next 4 Hrs · Dry Line Secure
🏎️ Track Thermal Loading Characteristic
Turn 2 is a massive 180° counter-clockwise carousel. Turn 9 (The Bypass / Over-The-Top) rewards patience over the blind crest.
🌧️ Wet Track Driving Line Notice
Exercise smooth inputs; painted curbing and pit exit lines hold standing water when damp.
🛰️ Live Circuit Doppler Weather Radar
Interactive animated radar loop centered over Thunderhill Raceway Park (3-Mile East). Use the bottom scrubber to track approaching convective cells.
⚙️ Vehicle Setup & Compound Parameters
Configure chassis weight, tire compound, and desired hot operating pressure.
Examples: Bridgestone RE-71RS, Nankang CR-S, Yokohama A052, Falken RT660, Michelin Cup 2
33 PSI Hot
26 PSI (Slicks / Light)33 PSI (Typical 200TW)40 PSI (Heavy Street)
🏁 Estimated Cold Starting Pressures
+9.3 PSI Thermal DeltaFront Starting (Cold)
26 PSI
Targets ~33 PSI Hot
Rear Starting (Cold)
26 PSI
Targets ~33 PSI Hot
⚠️ Chassis Cold Floor Protection Enforced (26 PSI): Calculated cold pressure fell below safe limits for Midweight (2,800 – 3,500 lbs). Starting lower risks tire carcass rollover, rim pinch flat, or shoulder delamination.
⏱️ The 60-Second Pit-In Rule: Hot tire pressures decay 1–2 PSI within minutes of leaving the track. Check hot pressures within 60 seconds of pulling into the pit box, then bleed excess to reach your exact target.
🌡️ Pyrometer Tire Temperature Diagnosis: Inside — Middle — Outside
How to read a probe tire pyrometer immediately after an HPDE session to distinguish pressure crowning from suspension camber alignment:
Ideal Track Camber Spread
Inside is 10°F to 15°F warmer than Outside
Shows healthy negative camber. The entire contact patch is utilized when the body rolls into high-speed apexes.
Over-Inflated (Tire Crowning)
Middle temp is > 4°F hotter than average of I and O
Tire center is bulging and bearing excess weight. Grip feels greasy. Action: Bleed 1.5 to 2.0 PSI hot.
Under-Inflated (Tire Dishing)
Middle temp is cooler than both Inside and Outside
Tire center is concave; load is concentrated on outer shoulders. Action: Add 1.5 to 2.0 PSI.
⚖️ Advisory & Legal Notice: Recommended tire starting pressures and meteorological compensations generated by this tool are educational approximations designed for closed-course driver education. Actual tire dynamics vary substantially based on vehicle curb weight, corner balancing, wheel rim width, static/dynamic camber and toe alignment, driver aggression, and tire manufacturer technical specifications. Always consult your tire manufacturer’s published minimum operating specifications.
🏎️ Session 1 Warmup Protocol: Never drop heavy street cars (BMW M, Mustang, Camaro) below 28–29 PSI cold before Session 1 in an attempt to reach an afternoon hot target. Cold radial tires on heavy platforms lack pneumatic sidewall stiffness before core heat builds; running excessively low cold pressures can cause catastrophic sidewall rollover, rim pinch flat, or shoulder delamination. Always stage your pressure drops over multiple sessions.
🚨 MANDATORY HIGHWAY RE-INFLATION WARNING: Tires bled down for optimal closed-circuit track grip will become dangerously under-inflated once cooled to ambient temperatures in the paddock. Drivers driving their vehicles home on public roads MUST re-inflate all tires to vehicle door jamb placard specifications using paddock compressed air before departing the speedway facility. Highway driving on track-bled cold tires risks catastrophic blowout, bead seal loss, and high-speed hydroplaning.
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💡
Chief Instructor Corner Notes
Turn 2 is a massive 180° counter-clockwise carousel. Turn 9 (The Bypass / Over-The-Top) rewards patience over the blind crest.
🎓
✓ Verified FacultyAccredited Circuit Instructors
MSF Level 2 certified coaches with check-ride authority
Travis Montgomery
Northern California Coach
🎖️ NASA NorCal Lead
⏱️ Thunderhill 25H Veteran
🛞
Asphalt Thermal Severity & Starting Bias
Corner loading profile tailored to Counter-Clockwise rotation
THERMAL SEVERITY PROFILE:
🔥 High (Counter-Clockwise Turn 2 Cyclone & Turn 9 Over-The-Top)
HIGHEST-STRESS CORNERS:
⚠️ Right-Front⚠️ Right-Rear
CURB AGGRESSIVENESS & SUSPENSION IMPACT:
📐 Moderate (The Cyclone crest requires straight wheels)
RECOMMENDED COLD PSI OFFSET BIAS:
LF-1 PSI
RF-3 PSI
LR-1 PSI
RR-2.5 PSI
⏱️
+ Submit Your Lap TimeLap Time Telemetry Benchmarks
Amateur HPDE reference brackets by run group & chassis
| CHASSIS | NOVICE | INTERMEDIATE | ADVANCED | RECORD |
|---|---|---|---|---|
| Porsche 911 GT3 RS | 2:04 | 1:56 | 1:50 | 1:43.8 |
| Corvette Z06 | 2:05 | 1:57 | 1:51 | 1:44.5 |
| BMW M2 / M3 | 2:14 | 2:05 | 1:58 | 1:51.2 |
| Spec Miata (NA/NB) | 2:26 | 2:15 | 2:07 | 2:00.6 |
⛽
Paddock Race Fuel & Facilities
ON-SITE FUEL GRADES:
⛽ 93 Octane⛽ 100 Unleaded⛽ 110 Leaded⛽ E85
PADDOCK AMENITIES:
✓ Clubhouse & Grill✓ Large Paddock Space✓ Covered Carports✓ Skidpad
PADDOCK NOISE CURFEW & QUIET HOURS:
🌙 20:00 to 07:00