BoP Lab / Buttonwillow Raceway Park

FE2 vs GT3U pace at Buttonwillow Raceway Park

Quickest here: FE2 1:39.265 Jon McClintock, Cal Club 2026 qualifying · GT3U 1:55.650 Michael Lewis, Cal Club 2025 race

Lap times% of FE2

FE2GT3Usolid race · dashed qualifying · slower is lower

FE2GT3Usolid race · dashed qualifying · each class's best lap as a share of FE2's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	FE2			GT3U
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FE2	% of FE2
	Cal Club 2026 CALCL262026-02-21	1:39.265Jon McClintock · fastest of 3 · top 3 within 1.5s-0.093s (-0.09%)	1:40.253Jon McClintock · fastest of 3 · top 3 within 2.2s+0.541s (+0.54%)	156.6Paul Marino+29.4 mph (+23.1%)
5 rule changes (FE2: 2, GT3U: 3)3 weight · 2 wording · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. · STU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. · STU GT3U minimum weight increases 150 to 250 pounds.showhide 2025-10-01 FE2 FE & FE2 Bubble Tail #38978wordingneutralFE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. 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. 2025-04-01 FE2 Driver Safety & Comfort #37965wordingneutralFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. 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	1:39.358Paul Marino · fastest of 4 · top 4 within 1.5s	1:39.712Paul Marino · fastest of 4 · top 4 within 1.7s	127.2Tom Hope	2:00.536Michael Lewis · fastest of 2	1:55.650Michael Lewis · fastest of 2	108.8Michael Lewis	+15.938squal +21.178s	116.0%qual 121.3%
2 earlier rule changes on record, in force before Cal Club 2025 (from 2019)1 weight · 1 wording · FE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.showhide 2020-09-01 FE2 FE/FE2 Oil Cooler #29293wordingneutralFE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. 2019-12-01 FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.

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 FE2" is the class's best as a share of FE2'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 FE2'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.