BoP Lab / Classes / FE2

FE2 vs SMX vs SRF vs FX pace at every track

Lap times across years say as much about the weather as the class. % of FE2 is each class's best lap as a share of FE2'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: remove one to add another)

ASB-SpecEPFAFCFE2×FFFPFVvsFX ×GT1GT2GTXHPPP2SMvsSMX ×vsSRF ×SRF3STLSTUT1T2T3T4Show 50 inactive classes

Series Runoffs Super Tour Both

Reference class · the yardstick the % column and chart are 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

Quickest here: FE2 1:35.040 Flinn Lazier, Runoffs 2018 qualifying · SMX 2:11.435 Nathan Nicholson, Runoffs 2023 qualifying · SRF 1:37.344 Mike Miserendino, Runoffs 2016 qualifying · FX 1:38.596 Vaughn Glace, Runoffs 2021 qualifying

% of FE2Lap times

FE2SMXSRFFXsolid race · dashed qualifying · slower is lower

FE2SMXSRFFXsolid 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, less is quicker, so up the chart is quicker

	Event	FE2			SMX					SRF					FX
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FE2	% of FE2	Qual best	Race best	Trap	vs FE2	% of FE2	Qual best	Race best	Trap	vs FE2	% of FE2
	Road America Runoffs 20262026-09-28	2:12.326Franklin Futrelle · fastest of 8 · top 5 within 1.9s-0.149s (-0.11%)	2:11.881Franklin Futrelle · fastest of 8 · top 5 within 1.6s-1.458s (-1.09%)	143.5Steve Whitston-5.5 mph (-3.7%)	2:36.472Skyler Cottrell · fastest of 21 · top 5 within 0.4s+0.240s (+0.15%)	2:36.414Cam Ebben · fastest of 21 · top 5 within 1.1s-0.677s (-0.43%)	128.4Christian Hoagland-0.6 mph (-0.5%)	+24.533squal +24.146s	118.6%qual 118.2%
7 rule changes (FE2: 1, SMX: 2, SRF: 3, FX: 1)2 engine · 1 cars added · 3 wording · 1 other · SRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting. · FX sealed engines now subject to section 9.3.42 requirements instead of full inspection and reassembly costs. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · SRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. · FE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only. · SRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.showhide 2026-09-01 SRF GCR Rain/Brake Light Correction #40579wordingwordingSRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting. 2026-08-01 FX Update sealed engine teardown section #40622wordingwordingFX sealed engines now subject to section 9.3.42 requirements instead of full inspection and reassembly costs. 2026-07-01 SMX Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. 2026-04-01 SMX Part Number Change Request #39914otherunclearSM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. 2026-03-01 SRF SRF3 Spark Plugs #39899engineengineSRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. 2025-10-01 FE2 FE & FE2 Bubble Tail #38978cars addedaddedFE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only. 2025-10-01 SRF Add HD Oil Cooler #38979engineadded · engineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
	Road America Runoffs 20252025-09-29	2:12.475Franklin Futrelle · fastest of 11 · top 5 within 1.4s+0.969s (+0.74%)	2:13.339Franklin Futrelle · fastest of 10 · top 5 within 0.6s+0.591s (+0.45%)	149.0Steve Whitston+3.7 mph (+2.6%)	2:36.232Cam Ebben · fastest of 20 · top 5 within 0.2s+0.581s (+0.37%)	2:37.091Michael Tinis · fastest of 19 · top 5 within 0.3s+0.813s (+0.52%)	129.1Camden Gruber-0.4 mph (-0.3%)	+23.752squal +23.757s	117.8%qual 117.9%
9 rule changes (FE2: 1, SMX: 5, SRF: 2, FX: 1)1 weight · 5 wording · 3 other · 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 fines, level 2 and 4 may carry $500 fines. · SMX tire marking rules clarified: one set Toyo RR P235/40/ZR17 per weekend, impound after first dry session, damaged tires may be replaced with used only. · SMX competitors must submit AiM data files within 60 minutes instead of 30 after timed sessions. · FE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook. · SRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only. · SRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. · FX Ligier JS F422 minimum weight reduces to 1360 lbs from 1375 lbs. · SMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation.showhide 2025-06-01 SMX SMX Data Submission - Penalties #38248otheraddedSMX 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 fines, level 2 and 4 may carry $500 fines. 2025-05-01 SMX Clarify Tire Marking Regs #38004wordingwordingSMX tire marking rules clarified: one set Toyo RR P235/40/ZR17 per weekend, impound after first dry session, damaged tires may be replaced with used only. 2025-05-01 SMX SMX Data Submission Timeframe #38039wordingwordingSMX competitors must submit AiM data files within 60 minutes instead of 30 after timed sessions. 2025-04-01 FE2 Driver Safety & Comfort #37965otheraddedFE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook. 2025-04-01 SRF Driver Safety & Comfort #37966otheraddedSRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only. 2025-04-01 SRF Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. 2024-12-01 FX Request to Change to Weight for Ligier JS F422 #37124weight -15 lbsfaster · weightFX Ligier JS F422 minimum weight reduces to 1360 lbs from 1375 lbs. 2024-12-01 SMX E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation.
	Road America Runoffs 20242024-10-01	2:11.506Porter Aiken · fastest of 18 · top 5 within 0.5s-1.300s (-0.98%)	2:12.748Porter Aiken · fastest of 17 · top 5 within 2.0s-0.523s (-0.39%)	145.3Porter Aiken+1.9 mph (+1.3%)	2:35.651Ethan Lampe · fastest of 23 · top 5 within 0.7s	2:36.278Ethan Jacobs · fastest of 22 · top 5 within 0.7s	129.5Michael Borden	+23.530squal +24.145s	117.7%qual 118.4%
18 rule changes (SMX: 4, SRF: 10, FX: 4)2 suspension & brakes · 1 cars added · 1 engine · 1 tyres & wheels · 1 weight · 7 wording · 5 other · SRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. · SRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. · SRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front. · SMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. · SM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. · SMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. · SM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · SRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement. · SRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified. · FX Ligier JS F4 1st Gen minimum weight drops 15 lbs to 1405; 2nd Gen rises 31 lbs to 1375. · FX adds Ligier JS F422 second generation classification, new car permitted. · FX Formula 4 removed reference to FIA Technical Regulations 2015 and subsequent safety requirements; tire choice remains unrestricted. · SRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch. · SRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit. · SRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A. · FX Formula Mazda specifications updated; attached table not provided. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.showhide 2024-10-01 SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. 2024-10-01 SRF Update SRF Brake Rotor Thickness #36687suspension & brakessuspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. 2024-10-01 SRF Hoosier Tire Decal Placement #36739wordingwordingSRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front. 2024-09-01 SMX SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. 2024-09-01 SMX Committee) AIM ECU Protocol #36556engineadded · engineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. 2024-09-01 SMX Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. 2024-09-01 SMX Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. 2024-09-01 SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. 2024-09-01 SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624wordingwordingSRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement. 2024-08-01 SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheelstyres & wheelsSRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified. 2024-07-01 FX Adjust minimum weights to align with pro F4 rules #36221weight -15 lbsfaster · weightFX Ligier JS F4 1st Gen minimum weight drops 15 lbs to 1405; 2nd Gen rises 31 lbs to 1375. 2024-04-01 FX Add Classification for 2nd Gen Ligier JS F422 #35844cars addedaddedFX adds Ligier JS F422 second generation classification, new car permitted. 2024-03-01 FX Clarify Formula 4 Rules in FX #35700wordingunclearFX Formula 4 removed reference to FIA Technical Regulations 2015 and subsequent safety requirements; tire choice remains unrestricted. 2024-01-01 SRF Update SRF Rain / Brake Rule #34706otherotherSRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch. 2024-01-01 SRF Update SRF Brake Light Rule v1 #34853otherotherSRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit. 2024-01-01 SRF SRF / SRF3 Rule Updates #35268suspension & brakessuspension & brakesSRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A. 2023-11-01 FX FM Rules Update #34841otherunclearFX Formula Mazda specifications updated; attached table not provided. 2023-10-01 SRF SRF Radiator Rule Update #34805otheraddedSRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.
	Virginia International Raceway Runoffs 20232023-09-23	1:50.665Charles Russell Turner · fastest of 26 · top 5 within 2.3s-0.188s (-0.17%)	1:51.098Franklin Futrelle · fastest of 19 · top 5 within 1.4s-20.947s (-15.86%)	141.3Franklin Futrelle-0.6 mph (-0.4%)	2:11.435Nathan Nicholson · fastest of 18 · top 5 within 0.6s	2:12.616Noah Harmon · fastest of 16 · top 5 within 0.1s	127.8Noah Harmon	+21.518squal +20.770s	119.4%qual 118.8%
6 rule changes (SRF: 3, FX: 3)2 tyres & wheels · 1 cars added · 1 engine · 1 weight · 1 wording · USF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. · SRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. · SRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. · SRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs. · FX: Remove FB and FM from combined-class preferences in GCR 1.4.2.D. · Formula Renault 2.0 (10-17) reclassified from FX to FA spec line; minimum weight reduced 1300 to 1280 lbs, restrictor removed.showhide 2023-06-01 FX 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 SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheelstyres & wheelsSRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. 2023-05-01 SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheelstyres & wheelsSRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. 2023-03-01 SRF Update SRF Brake Rule #33469enginefaster · engineSRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs. 2023-02-01 FX E&O - Remove references to FB and FM in GCR section 1.4.2.D #33725wordingwordingFX: Remove FB and FM from combined-class preferences in GCR 1.4.2.D. 2022-12-01 FX Reclassify 2010-2017 Formula Renault 2.0 as a spec line car in FA #33395weightfaster · weightFormula Renault 2.0 (10-17) reclassified from FX to FA spec line; minimum weight reduced 1300 to 1280 lbs, restrictor removed.
	Virginia International Raceway Runoffs 20222022-09-24	1:50.853Charles Russell Turner · fastest of 25 · top 5 within 1.1s-0.209s (-0.19%)	2:12.045Jason Conzo · fastest of 22 · top 5 within 1.8s+19.891s (+17.74%)	141.9Eric Cruz-0.6 mph (-0.5%)											1:51.480Trevor A Russell · fastest of 5 · top 5 within 9.7s	2:08.711Dimitrios Tsesmetzis · fastest of 4 · top 4 within 6.8s	137.2Trevor A Russell	-3.334squal +0.627s	97.5%qual 100.6%
12 rule changes (SRF: 3, FX: 9)3 tyres & wheels · 2 cars added · 1 engine · 1 induction · 1 weight · 2 wording · 2 other · Pro Formula F2000 tube frame transmission cut to 4 forward gears; sequential carries 25 lb. weight penalty. · FX Formula Mazda minimum weight set to 1270 lb. · FX Formula Mazda drops four-port Renesis engine option; weight minimum now per notes. · Formula Renault 2.0 (10-17) now requires 45mm Flat Plate Intake Restrictor; fairings before or after prohibited. · USF2000 Tube Frame adds Performance Electronics PE3-8400 ECU as alternative to Pectel T2. · SRF tire rule wording clarified: tires must be run as delivered. · SRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified. · Formula Mazda FX rule reference updated to current specifications document; tire marking no longer required. · FX Formula 4 tire choice unrestricted; must provide FIA certification rules upon request. · FX USF2000 Tube Frame front tyre changes from Hoosier radial 20.5 x 7.0 x 13 to any Hoosier 20.5 x 7.0 x 13. · FX Formula Renault 2.0 (00-09) and (10-17) tire choice unrestricted; no other component alterations except repairs. · SRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…showhide 2022-08-01 FX Pro Formula F2000/USF2000 Transmission E&O #32823engineslower · enginePro Formula F2000 tube frame transmission cut to 4 forward gears; sequential carries 25 lb. weight penalty. 2022-08-01 FX Formula Mazda Minimum Weight #33010weightslower · weightFX Formula Mazda minimum weight set to 1270 lb. 2022-08-01 FX Formula Mazda Spec Line E&O Corrections #33011cars addedremoved · cars addedFX Formula Mazda drops four-port Renesis engine option; weight minimum now per notes. 2022-07-01 FX Formula Renault 2.0 (10-17) Intake Restrictor #32745inductionslower · inductionFormula Renault 2.0 (10-17) now requires 45mm Flat Plate Intake Restrictor; fairings before or after prohibited. 2022-07-01 FX Allow Performance Electronics PE3-8400 for USF2000 MZR #32767cars addedaddedUSF2000 Tube Frame adds Performance Electronics PE3-8400 ECU as alternative to Pectel T2. 2022-06-01 SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered. 2022-06-01 SRF Brake, seal, and air filter clarifications #32670otherfasterSRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified. 2022-02-01 FX FM Rule Set Clarification #31881wordingwordingFormula Mazda FX rule reference updated to current specifications document; tire marking no longer required. 2022-02-01 FX E&O F4 Tires #31940tyres & wheelsadded · tyres & wheelsFX Formula 4 tire choice unrestricted; must provide FIA certification rules upon request. 2022-02-01 FX E&O USF2000 Tube Frame #31951tyres & wheelstyres & wheelsFX USF2000 Tube Frame front tyre changes from Hoosier radial 20.5 x 7.0 x 13 to any Hoosier 20.5 x 7.0 x 13. 2022-02-01 FX URGENT - FX- Formula Renault Tire #32058tyres & wheelsadded · tyres & wheelsFX Formula Renault 2.0 (00-09) and (10-17) tire choice unrestricted; no other component alterations except repairs. 2021-12-01 SRF Three Updates to SRF Rules #31523otherotherSRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:36.395Max Grau · fastest of 28 · top 5 within 0.7s	1:36.655Max Grau · fastest of 28 · top 5 within 0.7s	146.2Gray Fowler											1:38.596Vaughn Glace · fastest of 15 · top 5 within 4.1s	1:38.833Vaughn Glace · fastest of 15 · top 5 within 4.3s	138.6Vaughn Glace	+2.178squal +2.201s	102.3%qual 102.3%
11 rule changes (SRF: 6, FX: 5)3 cars added · 2 tyres & wheels · 1 engine · 3 wording · 2 other · FX USF2000 Tube Frame gains Hoosier radial tyre option, FC-compliant shocks, Wilwood brakes, and Bosch spark plugs. · SRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. · SRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive. · SRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing. · FX USF2000 Tube Frame now allows any Hoosier radial tire 20.5×7.0×13 front, 22.5×8.0×13 rear. · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · Formula Renault 2.0 / Fran-Am 2000 added to FX class at 1250 lbs with 8-inch front, 10-inch rear wheels, sealed engine. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · FX adds 2010–2017 Formula Renault 2.0, must comply with Table 1 notes. · FX FormulaSPEED FS2.0 now references online specifications instead of requiring World Speed Inc. documentation by April 2020. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.showhide 2021-08-01 FX Rules Adjustment #30950otheraddedFX USF2000 Tube Frame gains Hoosier radial tyre option, FC-compliant shocks, Wilwood brakes, and Bosch spark plugs. 2021-08-01 SRF SRF Wet Tires #30849tyres & wheelsadded · tyres & wheelsSRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. 2021-08-01 SRF SADEV-SRF3 Transmission #30926cars addedaddedSRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive. 2021-08-01 SRF SRF Update Maintenance, Repairs and Seals #30961wordingwordingSRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing. 2021-06-01 FX FX/FRP Tire Rule #30723tyres & wheelsadded · tyres & wheelsFX USF2000 Tube Frame now allows any Hoosier radial tire 20.5×7.0×13 front, 22.5×8.0×13 rear. 2021-06-01 SRF SRF3 Alternator Pulley #30684engineadded · engineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. 2021-05-01 FX Classify the 2000-2009 Formula Renault 2.0 / Fran-Am 2000 #30460cars addedaddedFormula Renault 2.0 / Fran-Am 2000 added to FX class at 1250 lbs with 8-inch front, 10-inch rear wheels, sealed engine. 2021-03-01 SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. 2021-01-01 FX Request for Car Classification to Compete in Formula X #29933cars addedaddedFX adds 2010–2017 Formula Renault 2.0, must comply with Table 1 notes. 2020-12-01 FX Update specifications for FormulaSPEED cars #29674wordingwordingFX FormulaSPEED FS2.0 now references online specifications instead of requiring World Speed Inc. documentation by April 2020. 2020-12-01 SRF SRF Shocks, Springs and Ride Height. #29688otherotherSRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.
	Road America Runoffs 20202020-10-02	2:12.806Scott Rettich · fastest of 25 · top 5 within 0.6s	2:13.271Owen McAllister · fastest of 23 · top 5 within 0.7s	143.4Owen McAllister											2:16.968Jacob Loomis · fastest of 12 · top 5 within 2.7s	2:17.553Jacob Loomis · fastest of 11 · top 5 within 3.5s	139.3Brad Drew	+4.282squal +4.162s	103.2%qual 103.1%
13 rule changes (FE2: 2, SRF: 5, FX: 6)4 cars added · 2 weight · 1 tyres & wheels · 6 wording · FE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed. · Formula Ireland / Formula FX added to FX class, must comply with Table 1 notes. · Formula Ireland/Formula FX cars pending specification submission for possible FX table addition. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · Ex-Pro Formula Super Vee added to FX with 1600cc VW engine, 1190 lb minimum weight, 6-inch front and 8-inch rear wheels. · FormulaSPEED with 2.0L Mazda MZR engine, 8in front/10in rear wheels, adjustable dual rear planes, 1350 lbs moves from FA to FX. · FX Formula Mazda no longer requires tire marking; must comply with December 2019 GCR rules. · Pro Formula F 2000 and USF2000 Tube Frame engine and car rules simplified; FC rules and FRP MAZDA MZR F2000 specs now apply directly. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · FE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited. · SRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.showhide 2020-09-01 FE2 FE/FE2 Oil Cooler #29293wordingwordingFE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed. 2020-09-01 FX Follow up to to Letter#28991 Request for FX classification #29281cars addedaddedFormula Ireland / Formula FX added to FX class, must comply with Table 1 notes. 2020-07-01 FX Request to be added to FX group #28991cars addedaddedFormula Ireland/Formula FX cars pending specification submission for possible FX table addition. 2020-05-01 SRF SRF Bump Stop Correction #27019wordingwordingSRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. 2020-04-01 FX Request to classify FSV in FX #28057cars addedaddedEx-Pro Formula Super Vee added to FX with 1600cc VW engine, 1190 lb minimum weight, 6-inch front and 8-inch rear wheels. 2020-04-01 FX Classify FormulaSPEED in FX #28715cars addedaddedFormulaSPEED with 2.0L Mazda MZR engine, 8in front/10in rear wheels, adjustable dual rear planes, 1350 lbs moves from FA to FX. 2020-03-01 FX Request to remove tire marking language from FM #28415wordingwordingFX Formula Mazda no longer requires tire marking; must comply with December 2019 GCR rules. 2020-02-01 FX Change to FX Table 1 #28322wordingunclearPro Formula F 2000 and USF2000 Tube Frame engine and car rules simplified; FC rules and FRP MAZDA MZR F2000 specs now apply directly. 202-01-01 SRF SRF Rain / Brake Rule - BoD approved as follows #34958wordingwordingSRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. 2019-12-01 FE2 FE / FE2 Update Rules #27624weightslower · weightFE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited. 2019-12-01 SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. 2019-12-01 SRF SRF / SRF3 Nose Weight Reduction #27706weightfaster · weightSRF front nose weight minimum reduced from 35 to 32 lbs. 2019-12-01 SRF SRF / SRF3 Majors & Regional Class Updates #27723wordingwordingSRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.
	Virginia International Raceway Runoffs 20192019-10-05	1:51.062Liam Snyder · fastest of 20 · top 5 within 1.3s	1:52.154Liam Snyder · fastest of 19 · top 5 within 0.7s	142.6Robert Vanman
1 rule change (SRF: 1)1 aero · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.showhide 2019-07-01 SRF SRF Dash Windscreen Kit #27028aeroadded · aeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.
	Sonoma Raceway Runoffs 20182018-10-10	1:35.040Flinn Lazier · fastest of 9 · top 5 within 1.5s	1:35.563Flinn Lazier · fastest of 9 · top 5 within 1.7s	126.8Scott Rettich
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25									1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19									1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21									2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s

By track

Track	Events	Typical % of FE2	Best	Latest
Road America	4	100.0%	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%1 of 2 with FE2	100.0%Runoffs 2021	100.0%Runoffs 2021
Daytona International Speedway	1	0 of 1 with FE2
Mid-Ohio Sports Car Course	1	0 of 1 with FE2
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 FE2's best on the same day: the weather, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. 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.