BoP Lab / Classes / P2

P2 vs STL vs FC pace at every track

Lap times across years say as much about the weather as the class. % of P2 is each class's best lap as a share of P2's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4)

AS +B-Spec +EP +FA +vsFC ×FE2 +FF +FP +FV +FX +GT1 +GT2 +GTX +HP +P +P2×SM +SMX +SRF3 +vsSTL ×STU +T1 +T2 +T3 +T4 +Show 51 inactive classes

Series Runoffs Super Tour Both

Reference · what % is measured against

Tracks · untick to narrow Auto Club Speedway Barber Motorsports Park Blackhawk Farms Raceway Buttonwillow Raceway Park Circuit of St. Louis (formerly Gateway Motorsports Circuit of the Americas Daytona International Speedway Grattan Raceway Hallett Motor Racing Circuit Homestead-Miami Speedway Indianapolis Motor Speedway Laguna Seca Michelin Raceway Road Atlanta Mid-Ohio Sports Car Course New Jersey Motorsports Park NOLA Motorsports Park Pacific Raceways Pittsburgh International Race Complex Portland International Raceway Pueblo Motorsports Park Road America Sebring International Raceway Sonoma Raceway Summit Point Raceway Thunderhill Raceway Park Virginia International Raceway Watkins Glen International Willow Springs Raceway World Wide Technology Raceway

Closest to the field: P2 100.0% of P2 Jeff Shafer, Daytona International Speedway Runoffs 2015 race · STL 94.1% of P2 Danny Steyn, Virginia International Raceway Runoffs 2022 race · FC 94.1% of P2 Nolan Allaer, Virginia International Raceway Runoffs 2022 race

% of P2Lap times

P2STLFCsolid race · dashed qualifying · slower is lower

P2STLFCsolid race · dashed qualifying · each class's best lap as a share of P2's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	P2			STL					FC
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs P2	% of P2	Qual best	Race best	Trap	vs P2	% of P2
	Road America Runoffs 20262026-09-28	2:10.606Greg Gyann · fastest of 11 · top 5 within 5.3s+3.201s (+2.51%)	2:09.441Mike Reupert · fastest of 11 · top 5 within 4.2s+1.119s (+0.87%)	155.0Matt Strand+2.4 mph (+1.6%)	2:30.537Derek Ketchie · fastest of 16 · top 5 within 2.9s-1.528s (-1.00%)	2:30.657Danny Steyn · fastest of 16 · top 5 within 0.6s-1.470s (-0.97%)	134.8Mike Taylor+2.6 mph (+2.0%)	+21.216squal +19.931s	116.4%qual 115.3%	2:10.686Brandon Dixon · fastest of 10 · top 5 within 4.0s-0.573s (-0.44%)	2:11.389Brandon Dixon · fastest of 10 · top 5 within 2.7s-1.435s (-1.08%)	143.3Dean Kiriluk-1.8 mph (-1.2%)	+1.948squal +0.080s	101.5%qual 100.1%
6 rule changes (STL: 4, FC: 2)2 cars added · 2 weight · 1 wording · 1 other · STL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · FC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential. · FC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.showhide 2026-07-01 STL Spec Line Clean Up #40344cars addedremovedcars addedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). 2026-06-01 STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. 2026-04-01 STL Classifications #39885cars addedaddedSTL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. 2026-01-01 FC F2000 MZR Spec Line Clarity/Revision Requested #38927otheraddedFC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential. 2026-01-01 FC Adjust F2000 Metrik ZF2 weight #39612weight -20 lbsfasterweightFC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs. 2026-01-01 STL Weight adjustment for STL #39579weightslowerweightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
	Road America Runoffs 20252025-09-29				2:32.065Jose Osiris Pena · fastest of 14 · top 5 within 3.4s+2.002s (+1.33%)	2:32.127Jose Osiris Pena · fastest of 13 · top 5 within 2.4s+1.882s (+1.25%)	132.2Jon Sewell-2.1 mph (-1.5%)			2:11.259Brandon Dixon · fastest of 10 · top 5 within 2.7s-0.367s (-0.28%)	2:12.824Brandon Dixon · fastest of 9 · top 5 within 2.3s+1.290s (+0.98%)	145.1Brandon Dixon+0.9 mph (+0.6%)
6 rule changes (P2: 1, STL: 3, FC: 2)3 weight · 1 cars added · 2 wording · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · P2 2000 cc Pinto engine car minimum weight set to 1335 lbs. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · FC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.showhide 2025-08-01 STL Lotus Weight Reduction #38772weight -50 lbsfasterweightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. 2025-05-01 STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. 2024-12-01 P2 2000 cc Pinto Engine Car Weight #37187weightslowerweightP2 2000 cc Pinto engine car minimum weight set to 1335 lbs. 2024-12-01 STL Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. 2024-11-01 FC 9.1.1.10.h. FC Tire Rule #36533wordingwordingFC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted. 2024-11-01 FC Change FF/FC Weight with Sequential Gearbox #36651weightfasterweightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.
	Road America Runoffs 20242024-10-01	2:07.405Bart Wolf · fastest of 14 · top 5 within 3.0s-1.109s (-0.86%)	2:08.322Bart Wolf · fastest of 13 · top 5 within 0.6s-1.471s (-1.13%)	152.5Lucian Pancea-0.6 mph (-0.4%)	2:30.063Joe Moser · fastest of 18 · top 5 within 3.7s-1.357s (-0.90%)	2:30.245Joe Moser · fastest of 16 · top 5 within 4.2s-1.870s (-1.23%)	134.3Joe Moser+1.3 mph (+1.0%)	+21.923squal +22.658s	117.1%qual 117.8%	2:11.626Timothy Minor · fastest of 10 · top 5 within 1.3s-1.018s (-0.77%)	2:11.534Michael Varacins · fastest of 9 · top 5 within 1.8s-2.074s (-1.55%)	144.2Michael Varacins+1.8 mph (+1.2%)	+3.212squal +4.221s	102.5%qual 103.3%
11 rule changes (P2: 5, STL: 4, FC: 2)3 engine · 2 weight · 1 aero · 1 cars added · 4 wording · P2 Spec Line E engine notes clarify oil system, ECU, and exhaust remain unrestricted; wording only. · P2 FIA Group CN notes clarify V de V European Proto Endurance Challenge bodywork, rear diffuser, wing, wheels, assisted shifting allowed; regulations link provided. · FC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · P2 AMAC and related cars: clarified B.1 modified engine range to 2008 and older stock engines only, with 38mm restrictor and 1025 lbs minimum weight. · P2 Suzuki GSX-R1000 engine: 2007–2008 crankcase 11300-21860 may be replaced with 2016–2019 GSX-S1000 part 11301-04840. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · P2 Table 1 engine date ranges clarified: Stock Engine replaced with specific marques Suzuki, Yamaha, Honda, BMW for 2009-newer and 2008-older rows.showhide 2024-05-01 P2 CN Spec ECU #35835wordingwordingP2 Spec Line E engine notes clarify oil system, ECU, and exhaust remain unrestricted; wording only. 2024-05-01 P2 E&O - Correct FIA Group CN spec line notes #35900wordingwordingP2 FIA Group CN notes clarify V de V European Proto Endurance Challenge bodywork, rear diffuser, wing, wheels, assisted shifting allowed; regulations link provided. 2024-04-01 FC Four Pot Calipers #35481cars addedaddedFC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted. 2024-02-01 STL ST Electric-Assisted Steering Systems #35066aeroaddedaeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. 2024-02-01 STL BOP Adjustments #35112weightfasterweightSTL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. 2024-02-01 STL Mazda 12A #35320engineremovedengineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. 2024-01-01 FC Please correct omitted punctuation #34890weight 2024-01-01 P2 E&O - Clarify B.1 modified engine range in AMAC spec lines #35225wordingwordingP2 AMAC and related cars: clarified B.1 modified engine range to 2008 and older stock engines only, with 38mm restrictor and 1025 lbs minimum weight. 2024-01-01 P2 Replacement Engine Crankcase for 07/08 Suzuki GSX-R1000 Engines #35340engineaddedengineP2 Suzuki GSX-R1000 engine: 2007–2008 crankcase 11300-21860 may be replaced with 2016–2019 GSX-S1000 part 11301-04840. 2024-01-01 STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineaddedengineSTL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. 2023-12-01 P2 Correct Table 1 for Engine Date Range Specifications #35182wordingwordingP2 Table 1 engine date ranges clarified: Stock Engine replaced with specific marques Suzuki, Yamaha, Honda, BMW for 2009-newer and 2008-older rows.
	Virginia International Raceway Runoffs 20232023-09-23	1:48.590Greg Gyann · fastest of 12 · top 5 within 1.7s+1.024s (+0.95%)	1:48.829Lucian Pancea · fastest of 11 · top 5 within 0.9s-27.005s (-19.88%)	150.9Lucian Pancea-0.2 mph (-0.2%)	2:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)	2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)	131.8Danny Steyn+0.1 mph (+0.1%)	+17.853squal +17.189s	116.4%qual 115.8%	1:50.281Nolan Allaer · fastest of 11 · top 5 within 2.3s+0.386s (+0.35%)	1:51.169Nolan Allaer · fastest of 11 · top 5 within 2.5s-16.690s (-13.05%)	143.5Robert Allaer+2.3 mph (+1.7%)	+2.340squal +1.691s	102.2%qual 101.6%
13 rule changes (P2: 8, STL: 2, FC: 3)3 cars added · 2 engine · 8 wording · FC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed. · USF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · P2 minimum side body height must equal front axle centerline height, viewed from side. · P2 closed cockpit single seat cars now prohibited unless Table 1 spec line permits. · P2 engine table spec line B.1 redundant effective date language removed and table updated. · P2 motorcycle restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weights increased to 1100 lbs for 2009+ engines; cockpit length corrected to 23.622 inches. · FC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35. · Sebeco NP01-EVO and Elan NP01 added to P2 with Mazda 2.0L MZR, no restrictor required, 1600 lb minimum weight. · P2 Radical SR3/SR4, Cup, Club Sport, Pro-Sport, PR6: assisted shifting clarified from A-assisted to Aassisted; Cup engine restrictor changed from Unrestricted to Not required. · P2 chassis now allows composite materials partially installed; anti-intrusion panels attachment simplified; Stohr and converted models clarified. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.showhide 2023-07-01 FC Review FC Runoffs Tire Marking Rule #34274wordingwordingFC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed. 2023-06-01 FC USF2000 Van Diemen with Mazda MZR LF-DE 2.0L in FC #34329cars addedaddedUSF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. 2023-06-01 STL Clarify STL table B - IT spec notes on Tires #34187wordingwordingSTL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. 2023-05-01 P2 Clarify minimum side body height requirement #34143wordingwordingP2 minimum side body height must equal front axle centerline height, viewed from side. 2023-05-01 P2 Clarify closed cockpit single seat car allowance #34144wordingwordingP2 closed cockpit single seat cars now prohibited unless Table 1 spec line permits. 2023-04-01 P2 Remove redundant effective date language and update engine table #34012wordingwordingP2 engine table spec line B.1 redundant effective date language removed and table updated. 2023-04-01 P2 E&O - Correct dimensional equivalents #34038enginefasterengineP2 motorcycle restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weights increased to 1100 lbs for 2009+ engines; cockpit length corrected to 23.622 inches. 2023-01-01 FC E&O 9.1.1.B.16.j #33634wordingwordingFC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35. 2023-01-01 P2 Request to Classify Sebeco NP01 #33378cars addedaddedSebeco NP01-EVO and Elan NP01 added to P2 with Mazda 2.0L MZR, no restrictor required, 1600 lb minimum weight. 2023-01-01 P2 Radical spec line clarifications #33485wordingwordingP2 Radical SR3/SR4, Cup, Club Sport, Pro-Sport, PR6: assisted shifting clarified from A-assisted to Aassisted; Cup engine restrictor changed from Unrestricted to Not required. 2023-01-01 P2 E&O original class intent #33519wordingwordingP2 chassis now allows composite materials partially installed; anti-intrusion panels attachment simplified; Stohr and converted models clarified. 2023-01-01 P2 Update Engine Table Spec Line B.1 #33608engine 2023-01-01 STL Spec MX5 in STL #33473cars addedaddedSpec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.
	Virginia International Raceway Runoffs 20222022-09-24	1:47.566Tim Day Jr · fastest of 12 · top 5 within 3.0s-1.545s (-1.42%)	2:15.834Greg Gyann · fastest of 12 · top 5 within 10.1s+25.576s (+23.20%)	151.1Robert Iversen+1.8 mph (+1.2%)	2:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)	2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)	131.7Trever Degioanni-3.2 mph (-2.3%)	-8.002squal +17.908s	94.1%qual 116.6%	1:49.895Nolan Allaer · fastest of 12 · top 5 within 1.5s-1.305s (-1.17%)	2:07.859Nolan Allaer · fastest of 13 · top 5 within 3.8s+15.685s (+13.98%)	141.2Tim Minor-0.6 mph (-0.4%)	-7.975squal +2.329s	94.1%qual 102.2%
20 rule changes (P2: 10, STL: 5, FC: 5)2 weight · 1 cars added · 1 engine · 1 tyres & wheels · 14 wording · 1 other · FC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50. · P2 chassis construction clarified: full composite allowed; partial composite must roll without composite parts installed. · P2 classification wording cleaned up in GCR section 9.1.8.C and GCR contents. · P2 Oldsmobile cam rules correct spelling from 'after market' to 'aftermarket' in two sections. · P2 adds Beasley B2 at 1350 lbs with Mazda 12A, 40.5mm venturi, and up to 16.5in wing chord. · P2 wings: terminology change from 'cord' to 'chord', and 'only' removed from Bobsy and Jondal notes. · P2 Converted F5 cars renamed F500, must retain F500 suspension, minimum width 55 inches. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · P2 motorcycle engines gain 5cc to 1505cc max, two-stroke gains 5cc to 1205cc max, automotive engines add 50 lbs minimum weight to 1350 lbs. · FC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions. · P2 Control Area definition clarified: rectangular zone from rear edge of front tires to front edge of rear tires, full car width. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · FC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website. · P2 specification line B.1 engine table entry amended; details of change not provided in excerpt. · P2 Control Area definition clarified: rear tire edge and front tire edge bounds, car's lower surface width, floor extensions and aerodynamic attachments included, vertical structures prohibited. · FC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side. · FC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.showhide 2022-07-01 FC Add Specification to Performance Electronics ECU for Ford Zetec #32761wordingwordingFC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50. 2022-05-01 P2 E&O Clarification of Chassis Construction Requirements #32469wordingwordingP2 chassis construction clarified: full composite allowed; partial composite must roll without composite parts installed. 2022-05-01 P2 Clean up P2 wording #32525wordingwordingP2 classification wording cleaned up in GCR section 9.1.8.C and GCR contents. 2022-04-01 P2 After Market to Aftermarket #32373wordingwordingP2 Oldsmobile cam rules correct spelling from 'after market' to 'aftermarket' in two sections. 2022-03-01 P2 Add spec line for Beasley B2 #32147cars addedaddedP2 adds Beasley B2 at 1350 lbs with Mazda 12A, 40.5mm venturi, and up to 16.5in wing chord. 2022-03-01 P2 E&O Table 1 spec line wing terminology #32148wordingwordingP2 wings: terminology change from 'cord' to 'chord', and 'only' removed from Bobsy and Jondal notes. 2022-03-01 P2 E&O class name #32196wordingwordingP2 Converted F5 cars renamed F500, must retain F500 suspension, minimum width 55 inches. 2022-03-01 STL Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. 2022-03-01 STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. 2022-02-01 P2 E&O Engine section #31969weightslowerweightP2 motorcycle engines gain 5cc to 1505cc max, two-stroke gains 5cc to 1205cc max, automotive engines add 50 lbs minimum weight to 1350 lbs. 2022-01-01 FC Clean up Chassis/Frame section #31867wordingwordingFC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions. 2022-01-01 P2 E&O letter #31539 – Control Area definition #31783wordingwordingP2 Control Area definition clarified: rectangular zone from rear edge of front tires to front edge of rear tires, full car width. 2022-01-01 STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. 2022-01-01 STL Mazda Renesis Restriction #31467enginefasterengineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. 2022-01-01 STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. 2021-12-01 FC Clarify Zetec ECU requirements #31554wordingwordingFC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website. 2021-12-01 P2 BoP adjustment effective 1-1-22 #31538otherunclearP2 specification line B.1 engine table entry amended; details of change not provided in excerpt. 2021-12-01 P2 E&O clarification of "Control Area" definition #31539wordingwordingP2 Control Area definition clarified: rear tire edge and front tire edge bounds, car's lower surface width, floor extensions and aerodynamic attachments included, vertical structures prohibited. 2021-11-01 FC Clarify composite anti-intrusion panel language #31426wordingwordingFC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side. 2021-11-01 FC Clarify tire marking requirements #31455wordingwordingFC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:33.235Tim Day Jr · fastest of 16 · top 5 within 3.3s+1.409s (+1.53%)	1:35.322Tim Day Jr · fastest of 10 · top 5 within 4.8s+2.841s (+3.07%)	150.3Robert Iversen	1:51.665Danny Steyn · fastest of 42 · top 5 within 1.7s-0.982s (-0.87%)	2:02.711Joe Moser · fastest of 37 · top 5 within 3.2s+10.122s (+8.99%)	131.8Max Gee	+27.389squal +18.430s	128.7%qual 119.8%	1:36.787Trent Walko · fastest of 31 · top 5 within 1.7s+0.451s (+0.47%)	1:36.980Simon Sikes · fastest of 31 · top 5 within 2.0s+0.090s (+0.09%)	141.6Tim Minor	+1.658squal +3.552s	101.7%qual 103.8%
24 rule changes (P2: 8, STL: 15, FC: 1)5 engine · 3 cars added · 3 weight · 2 aero · 1 induction · 1 suspension & brakes · 7 wording · 2 other · P2 CN Honda K20A-FD2 engine rebuild clarified: balancing, porting, polishing prohibited; valve jobs and honing must follow factory procedures. · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · P2 Converted F5 cars must retain F5 suspension and meet P2 non-spec requirements except minimum width is 55 inches. · P2 minimum body width clarified: cannot extend inward beyond vertical plane through tire centerlines. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · P2 tonneau covers now allowed to meet minimum dimensions; cockpit equipment attachment wording clarified. · P2 removes effective date 01/01/2021 from six car spec lines in Table 1. · P2 engine specs B.1, B.2, B.3 limited to maximum 4 valves per cylinder. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · FC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210. · P2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front, 14–15 rear wheel width. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · P2 motorcycle-engine cars: 2009+ stock 37mm restrictor, 2008- stock 35mm, modified 1075 lbs. Honda K20A 50mm restrictor. Various spec cars: restrictors increased or decreased 0.5–3mm. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.showhide 2021-09-01 P2 P2 CN Engine Rebuild Clarification #31000wordingwordingP2 CN Honda K20A-FD2 engine rebuild clarified: balancing, porting, polishing prohibited; valve jobs and honing must follow factory procedures. 2021-09-01 STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. 2021-08-01 P2 F5 P2 Conversion #30856wordingwordingP2 Converted F5 cars must retain F5 suspension and meet P2 non-spec requirements except minimum width is 55 inches. 2021-08-01 P2 Clarify minimum body width requirement #30859wordingwordingP2 minimum body width clarified: cannot extend inward beyond vertical plane through tire centerlines. 2021-06-01 STL VW Engine Request #30625engineaddedengineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. 2021-05-01 P2 E&O tonneau cover provision in cockpit opening section #30459wordingwordingP2 tonneau covers now allowed to meet minimum dimensions; cockpit equipment attachment wording clarified. 2021-05-01 P2 Remove effective dates in Table 1 #30468wordingwordingP2 removes effective date 01/01/2021 from six car spec lines in Table 1. 2021-05-01 P2 E&O Maximum Valves Per Cylinder #30560engineengineP2 engine specs B.1, B.2, B.3 limited to maximum 4 valves per cylinder. 2021-05-01 STL Solstice Ride Height #30183otheraddedSTL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. 2021-05-01 STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations. 2021-05-01 STL Honda B16A (JDM) Restrictor change #30531engineslowerengineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. 2021-04-01 STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. 2021-03-01 FC Request for FC Weight Change #30171weightfasterweightFC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210. 2021-03-01 P2 Add a new spec line for a 2-cycle, 3-cylinder engine up to 820cc #30272cars addedaddedP2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front, 14–15 rear wheel width. 2021-03-01 STL GM Ecotec engines in STL #30247engineaddedengineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. 2021-03-01 STL Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. 2021-02-01 STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. 2021-02-01 STL Super Touring Wing Clarification #30111aeroaeroSTL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. 2021-02-01 STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. 2021-01-01 STL Request for FWD and RWD Parity #29728weightfasterweightSTL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. 2021-01-01 STL Request to Remove Honda F20C 2% Weight Penalty #29815weightfasterweightSTL Honda F20C drops 2% weight penalty, minimum weight reduced. 2021-01-01 STL Request for FWD and RWD Parity #30023inductionslowerinductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. 2020-12-01 P2 Balance of Performance adjustments effective 01-01-2021 #29822engineunclearP2 motorcycle-engine cars: 2009+ stock 37mm restrictor, 2008- stock 35mm, modified 1075 lbs. Honda K20A 50mm restrictor. Various spec cars: restrictors increased or decreased 0.5–3mm. 2020-12-01 STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
	Road America Runoffs 20202020-10-02	2:08.514Robert Iversen · fastest of 12 · top 5 within 3.0s	2:09.793Robert Iversen · fastest of 12 · top 5 within 3.9s	153.1Robert Iversen	2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s	2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s	132.9Darin Treakle	+22.322squal +22.906s	117.2%qual 117.8%	2:12.644Robert Allaer · fastest of 13 · top 5 within 2.1s	2:13.608Robert Allaer · fastest of 11 · top 5 within 1.2s	142.4Robert Allaer	+3.815squal +4.130s	102.9%qual 103.2%
21 rule changes (P2: 6, STL: 11, FC: 4)7 engine · 5 cars added · 1 aero · 1 induction · 1 weight · 5 wording · 1 other · FC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder. · P2 rear wing rules clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 1-meter formula wing 110cm wide, 9×18 inches, end plates 14×18 inches. · FC Zetec engine minimum weight increases 20 lbs to 1220 lbs. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · Elan NP01 added to P2 Table 1 as Spec Line car with 2000cc displacement and 42mm restrictor. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · P2 Enterprises Sports Racer now permits 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · P2 Enterprise Sports Racer 2.3L engine must use SIR or Flat Plate restrictor meeting peak horsepower, sized in whole or 0.5mm increments. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · P2 electronic throttle control wording clarified: ETC permitted if stock ECU throttle pedal activates original throttle shaft mechanism. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · P2 adds BMW to permitted motorcycle-based engines alongside Kawasaki, Suzuki, Yamaha, Honda. · FC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only. · FC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763.showhide 2020-10-01 FC Urgent: SCCA PE3 map unsuitable #29475wordingwordingFC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder. 2020-09-01 P2 E&O clarification of P2 rear wing requirements #29205aeroaeroP2 rear wing rules clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 1-meter formula wing 110cm wide, 9×18 inches, end plates 14×18 inches. 2020-08-01 FC Request for weight adjustments to equalize FC competition. #28888weightslowerweightFC Zetec engine minimum weight increases 20 lbs to 1220 lbs. 2020-08-01 STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. 2020-08-01 STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. 2020-07-01 STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. 2020-06-01 P2 Classify Elan NP01 in P2 Table 1 #28812cars addedaddedElan NP01 added to P2 Table 1 as Spec Line car with 2000cc displacement and 42mm restrictor. 2020-06-01 STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedaddedSTL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. 2020-06-01 STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. 2020-06-01 STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. 2020-05-01 P2 SCCA Enterprises ESR / P2 engine restrictor testing #28669otheraddedP2 Enterprises Sports Racer now permits 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR. 2020-05-01 STL STL Honda B18 restrictor changes #28794enginefasterengineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. 2020-04-01 P2 Add ESR inlet restrictor #27869inductionaddedinductionP2 Enterprise Sports Racer 2.3L engine must use SIR or Flat Plate restrictor meeting peak horsepower, sized in whole or 0.5mm increments. 2020-04-01 STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineaddedengineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. 2020-04-01 STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslowerengineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm. 2020-04-01 STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslowerengineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm. 2020-03-01 P2 Request for Fly by Wire Rule Wording Change #28247wordingwordingP2 electronic throttle control wording clarified: ETC permitted if stock ECU throttle pedal activates original throttle shaft mechanism. 2020-03-01 STL Request to add wheel part numbers #28342cars addedaddedSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. 2020-01-01 P2 Request for addition of BMW Engine in P2 Engine Table #27821engineaddedengineP2 adds BMW to permitted motorcycle-based engines alongside Kawasaki, Suzuki, Yamaha, Honda. 2019-12-01 FC Request for Better Zetec Connecting Rods #27710engineaddedengineFC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only. 2019-12-01 FC Add Alternate Piston #27795engineaddedengineFC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763.
	Virginia International Raceway Runoffs 20192019-10-05	1:49.111Robert Iversen · fastest of 14 · top 5 within 0.8s	1:50.258Greg Gyann · fastest of 13 · top 5 within 0.4s	149.4Robert Iversen	2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s	2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s	134.8Cliff Ira	+17.015squal +18.092s	115.4%qual 116.6%	1:51.200Robert Allaer · fastest of 10 · top 5 within 3.1s	1:52.174Robert Allaer · fastest of 9 · top 5 within 2.7s	141.8Robert Allaer	+1.916squal +2.089s	101.7%qual 101.9%
22 rule changes (P2: 9, STL: 11, FC: 2)7 engine · 4 cars added · 2 weight · 1 induction · 6 wording · 2 other · P2 Honda K20A-FD2 non-composite chassis intake restrictor note clarified; restrictor implementation date removed. · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · P2 motorcycle engines: Stock restrictor to 35mm, Modified to 34mm; weights up to 1025 and 1125 lbs respectively. B.5 restrictor to 33mm, weight to 1185 lbs. · P2 cars limited to power application on maximum two wheels. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · P2 Enterprise minimum weight increased to 1375 lbs.; peak horsepower of sealed ESR engine reduced per CRB specification. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · FC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · P2 stock and modified engines get smaller restrictors (35.0mm, 34.0mm, 33.0mm) and heavier minimums (1025, 1125, 1185 lbs). · P2 Line A.1 restrictor reduced from 40mm to 38mm. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · FC Wiseco piston and connecting rod minimum weight corrected to 976 grams. · P2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lb minimum with 30mm restrictor. · P2 Group CN Honda K20A-FD2 55mm intake restrictor implementation delayed from 1 January to 3 March 2019. · P2 Honda K20A-FD2 Group CN must use stock intake manifold, 64mm throttle, 55mm restrictor at 1500 lbs minimum. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.showhide 2019-10-01 P2 Update Engine Table Line E notes #27414wordingwordingP2 Honda K20A-FD2 non-composite chassis intake restrictor note clarified; restrictor implementation date removed. 2019-10-01 STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedaddedSTL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. 2019-08-31 P2 Update P2 Engine Table spec lines to reflect 3/1/2019 #27254engineslowerengineP2 motorcycle engines: Stock restrictor to 35mm, Modified to 34mm; weights up to 1025 and 1125 lbs respectively. B.5 restrictor to 33mm, weight to 1185 lbs. 2019-07-01 P2 E&O Transmissions #27006engineslowerengineP2 cars limited to power application on maximum two wheels. 2019-07-01 STL Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. 2019-06-01 P2 Request to restrict all cars #26246weightslowerweightP2 Enterprise minimum weight increased to 1375 lbs.; peak horsepower of sealed ESR engine reduced per CRB specification. 2019-05-31 STL Request Restrictor Plate correction #26779enginefasterengineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. 2019-05-01 FC E&O Wiseco piston and Crower connecting rod #26659wordingwordingFC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams. 2019-05-01 STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. 2019-03-01 P2 Change Engine Table Lines B.1 & B.5 #25777inductionslowerinductionP2 stock and modified engines get smaller restrictors (35.0mm, 34.0mm, 33.0mm) and heavier minimums (1025, 1125, 1185 lbs). 2019-03-01 P2 Change Line A.1 restrictor size #26429engineslowerengineP2 Line A.1 restrictor reduced from 40mm to 38mm. 2019-03-01 STL Request to Allow VW 1.8L Engine #25614cars addedaddedSTL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. 2019-03-01 STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterweightSTL Mazda Renesis minimum weight reduced to 2700 lbs. 2019-03-01 STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open. 2019-03-01 STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedaddedSTL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. 2019-03-01 STL Port Matching #26415enginefasterengineSTL Mazda 12 and 13B now permit port matching; porting ban removed. 2019-01-01 FC Correct Wiseco piston and connecting rod #25809wordingwordingFC Wiseco piston and connecting rod minimum weight corrected to 976 grams. 2019-01-01 P2 Request to Allow 1345cc Hayabusa Engines for Spec Line P2 Cars #25595cars addedaddedP2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lb minimum with 30mm restrictor. 2019-01-01 P2 Change CN inlet restrictor implementation date #25816wordingwordingP2 Group CN Honda K20A-FD2 55mm intake restrictor implementation delayed from 1 January to 3 March 2019. 2019-01-01 P2 Clarify Honda K20A-FD2 parts requirement #25950engineslowerengineP2 Honda K20A-FD2 Group CN must use stock intake manifold, 64mm throttle, 55mm restrictor at 1500 lbs minimum. 2019-01-01 STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefasterengineSTL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. 2019-01-01 STL Request E&O for Mazda Miata Spec Line #25955otherunclearSTL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.
	Sonoma Raceway Runoffs 20182018-10-10	1:28.784Tim Day Jr · fastest of 17 · top 5 within 5.0s	1:32.071Chuck Bona · fastest of 18 · top 5 within 0.9s	144.4Tim Day Jr	1:49.138Danny Steyn · fastest of 19 · top 5 within 2.5s	1:49.754Danny Steyn · fastest of 17 · top 5 within 2.5s	103.2Craig McHaffie	+17.683squal +20.354s	119.2%qual 122.9%	1:32.571Timothy de Silva · fastest of 16 · top 5 within 1.8s	1:34.053Mitch Egner · fastest of 12 · top 5 within 1.6s	133.1Robert Armington	+1.982squal +3.787s	102.2%qual 104.3%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:31.826Jeff Shafer · fastest of 26 · top 5 within 4.9s	1:32.481Jeff Shafer · fastest of 24 · top 5 within 3.8s		1:52.647Adam Roberts · fastest of 57 · top 5 within 0.8s	1:52.589Eric Kutil · fastest of 50 · top 5 within 1.2s		+20.108squal +20.821s	121.7%qual 122.7%	1:36.336Austin McCusker · fastest of 14 · top 5 within 2.3s	1:36.890Tim Minor · fastest of 14 · top 5 within 3.8s		+4.409squal +4.510s	104.8%qual 104.9%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:20.188Jeff Shafer · fastest of 18 · top 5 within 4.0s	1:20.904Jeff Shafer · fastest of 16 · top 5 within 2.2s		1:35.439John Schmitt · fastest of 34 · top 5 within 1.5s	1:36.625Kevin Boehm · fastest of 31 · top 5 within 0.6s		+15.721squal +15.251s	119.4%qual 119.0%	1:21.962John LaRue · fastest of 7 · top 5 within 2.6s	1:22.049Nigel Saurino · fastest of 7 · top 5 within 3.0s		+1.145squal +1.774s	101.4%qual 102.2%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:51.825Chris Farrell · fastest of 17 · top 5 within 3.6s	1:52.355Jeff Shafer · fastest of 17 · top 5 within 2.8s		2:09.672Kevin Boehm · fastest of 37 · top 5 within 2.5s	2:10.269Kevin Boehm · fastest of 37 · top 5 within 2.1s		+17.914squal +17.847s	115.9%qual 116.0%	1:54.477Yufeng Luo · fastest of 11 · top 5 within 2.5s	1:55.135Yufeng Luo · fastest of 10 · top 5 within 2.1s		+2.780squal +2.652s	102.5%qual 102.4%

By track

Track	Events	Typical % of P2	Best	Latest
Road America	4	100.0%3 of 4 with P2	100.0%Runoffs 2020	100.0%Runoffs 2026
Virginia International Raceway	3	100.0%	100.0%Runoffs 2019	100.0%Runoffs 2023
Indianapolis Motor Speedway	2	100.0%	100.0%Runoffs 2017	100.0%Runoffs 2021
Daytona International Speedway	1	100.0%	100.0%Runoffs 2015	100.0%Runoffs 2015
Mid-Ohio Sports Car Course	1	100.0%	100.0%Runoffs 2016	100.0%Runoffs 2016
Sonoma Raceway	1	100.0%	100.0%Runoffs 2018	100.0%Runoffs 2018

About this data

Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of P2's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.