BoP Lab / Buttonwillow Raceway Park

GT3U vs SMX pace at Buttonwillow Raceway Park

Quickest here: GT3U 1:55.650 Michael Lewis, Cal Club 2025 race · SMX 1:56.431 Ethan Lampe, Cal Club 2025 qualifying

Lap times% of GT3U

GT3USMXsolid race · dashed qualifying · slower is lower

GT3USMXsolid race · dashed qualifying · each class's best lap as a share of GT3U's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	GT3U			SMX
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs GT3U	% of GT3U
	Cal Club 2026 CALCL262026-02-21				1:56.503Lincoln Larson · fastest of 15 · top 5 within 0.7s+0.072s (+0.06%)	1:57.973William Wallis · fastest of 15 · top 5 within 0.8s+0.556s (+0.47%)	141.6Joey Andrews+28.0 mph (+24.6%)
7 rule changes (GT3U: 3, SMX: 4)3 weight · 4 wording · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · SMX Toyo RR P235/40/ZR17 tire rules clarified: one set per weekend, marking after first session, damage replacement procedures revised. · SMX data submission deadline extended from 30 to 60 minutes after each timed session. · STU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. · STU GT3U minimum weight increases 150 to 250 pounds.showhide 2025-06-01 SMX SMX Data Submission - Penalties #38248wordingwordingSMX drivers must submit data acquisition files on time or face suspension and $250 fine. 2025-06-01 SMX Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine. 2025-05-01 GT3U Table C: STU-GT3U Clarification #38268weightfasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. 2025-05-01 SMX Clarify Tire Marking Regs #38004wordingwordingSMX Toyo RR P235/40/ZR17 tire rules clarified: one set per weekend, marking after first session, damage replacement procedures revised. 2025-05-01 SMX SMX Data Submission Timeframe #38039wordingwordingSMX data submission deadline extended from 30 to 60 minutes after each timed session. 2025-04-01 GT3U TCR Rulesets #37981weightfasterSTU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. 2025-03-01 GT3U Increase Minimum Weight #37919weight +100 lbsslowerSTU GT3U minimum weight increases 150 to 250 pounds.
	Cal Club 2025 CALCL252025-02-22	2:00.536Michael Lewis · fastest of 2	1:55.650Michael Lewis · fastest of 2	108.8Michael Lewis	1:56.431Ethan Lampe · fastest of 15 · top 5 within 1.5s	1:57.417Ethan Lampe · fastest of 15 · top 5 within 1.6s	113.6Ryan Gutile	+1.767squal -4.105s	101.5%qual 96.6%
5 earlier rule changes on record, in force before Cal Club 2025 (from 2024)5 wording · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · SMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification. · SMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance. · SMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1. · SM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed.showhide 2024-12-01 SMX E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. 2024-09-01 SMX SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification. 2024-09-01 SMX Committee) AIM ECU Protocol #36556wordingwordingSMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance. 2024-09-01 SMX Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1. 2024-09-01 SMX Committee) Shifter Bushing #36611wordingwordingSM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed.

Best is the class's fastest lap in that event's qualifying or race sessions, with the driver who set it, how many cars set a time that session and how close the top five were; a best from fewer than three cars is greyed. With two or more classes, "vs" is the gap of each class's best to the first class's at the same event. "% of GT3U" is the class's best as a share of GT3U's best at the same event (100% is level, less is quicker): weather and track condition move every class together, so this compares across years where the raw times do not. It still breaks when GT3U's own field changes or one session was wet and another dry. Newest event first. The coloured figure under each value is the change from the previous event that has one (green is quicker, red slower). Whole laps only, so events with different sector layouts still compare. Weather and track condition are not accounted for.