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BoP Lab / Buttonwillow Raceway Park

SRF3 + STL + STU at Buttonwillow Raceway Park

No mapCal Club 2024, Cal Club 2023

Track map: sectors and speed trap

Track map with timing sectors and speed trap
Shown for: Cal Club 2026 (practice, qualifying, race) · Cal Club 2025 (practice, qualifying, race)
Class · click a class to switch, + to compare alongside
Track configuration
Events

This track has been raced on 4 configurations (The Circuit, 2.57 mi; 2.92 mi; 1.83 mi; 3.02 mi). Laps on different configurations are not comparable, so only events on the 2.57 mile layout are shown; switch above to see the others.

One run is left out as not that car's own laps (far quicker than the car managed in any other session and than anyone else in its class all week; usually a swapped transponder): Tom Burt in Cal Club 2025 PM (1:42.300; the car's best in any other session was 1:52.334 and the rest of the class's best all week 1:50.233).

6 laps are left out as timing errors (far too short to be a lap of this track). The rest of those sessions, sectors included, is used.

PosCarDriverClass#LapTheoreticalQualRace5-lap stintConsistencyTrapS1S2S3
1SCCA Ent SRF3Caleb ShraderSRF3991:50.233 B-Q21:49.9671:50.233 B-Q21:50.825 B-R21:51.100 B-R2+0.469 B-R2133.6 A-Q230.136 B-P31.672 B-P48.159 B-P
2SCCA Ent SRF3Calvin HarrisSRF3421:50.359 B-Q21:50.3391:50.359 B-Q21:51.127 B-R21:51.474 B-R2+0.477 B-R2112.4 B-Q230.212 B-Q231.791 B-Q248.336 B-Q2
3SCCA Ent SRF3John BlackSRF3171:50.578 B-Q21:50.2651:50.578 B-Q21:50.980 B-R11:51.262 B-R1+0.649 B-R1134.8 A-P30.260 B-Q231.841 B-Q148.164 B-Q1
4SCCA Ent SRF3Todd HarrisSRF3241:50.578 B-Q21:50.5781:50.578 B-Q21:51.673 B-R11:51.973 B-R2+0.681 B-R2110.6 B-R130.259 B-Q231.845 B-Q248.474 B-Q2
5SCCA Ent SRF3Taylor HarrisSRF3121:50.673 B-Q21:50.5891:50.673 B-Q21:51.241 B-R21:51.430 B-R2+0.243 B-R2114.1 B-R130.347 B-Q231.916 B-Q248.326 B-Q2
6SCCA Ent SRF3Mike MiserendinoSRF3111:50.810 B-Q21:50.2821:50.810 B-Q21:51.796 B-R21:52.073 B-R2+0.352 B-R2135.7 A-Q230.282 B-Q232.022 B-R147.978 A-P
7SCCA Ent SRF3Steve FoggSRF3211:50.892 B-Q21:50.7701:50.892 B-Q21:51.698 B-R11:51.962 B-R2+0.636 B-R2129.9 A-R1, A-Q230.379 B-Q232.043 B-Q248.348 B-Q2
8SCCA Ent SRF3Asad NikadambaevSRF31441:50.913 A-Q21:50.9131:50.913 A-Q21:52.070 A-R21:52.270 A-R2+0.491 A-R2136.8 A-Q130.477 A-Q231.965 A-Q248.471 A-Q2
9Mazda RX-3Tony RiveraSTU091:50.913 A-Q21:50.8701:50.913 A-Q21:52.737 A-R21:54.126 A-R2+2.638 A-R2135.2 A-Q230.415 A-Q232.456 A-Q247.999 A-Q2
10SCCA Ent SRF3TJ AckerSRF3621:51.005 B-Q21:50.8441:51.005 B-Q21:51.755 B-R21:52.016 B-R1+0.510 B-R1110.3 B-Q130.314 B-Q232.118 B-Q248.412 B-Q2
11SCCA Ent SRF3Robert EdmisonSRF3221:51.118 B-P1:50.5651:51.136 B-Q21:51.601 B-R21:52.033 B-R2+1.171 B-R2136.5 A-P30.175 B-Q131.846 B-Q148.544 B-Q1
12SCCA Ent SRF3EJ AbedSRF3271:51.304 B-Q21:51.2141:51.304 B-Q21:52.103 B-R21:52.228 B-R2+0.387 B-R2136.8 A-Q130.360 B-Q232.113 B-Q248.741 B-Q2
13SCCA Ent SRF3Sean O'BoyleSRF3671:51.453 B-P1:51.2481:51.799 B-Q21:52.231 B-R21:52.285 B-R2+0.523 B-R2135.9 A-R230.363 B-P32.200 B-P48.685 B-P
14Mazda MiataWhitfield GreggSTU171:51.602 B-P1:51.6022:02.264 B-Q22:01.538 B-R12:02.222 B-R1+1.271 B-R1116.3 A-Q130.652 B-P32.263 B-P48.687 B-P
15Mazda MX-5Jared KorthSTL271:51.665 B-P1:51.6451:58.002 A-R21:58.825 A-R2+1.245 A-R2134.8 A-R1, A-R230.616 B-P32.218 B-P48.811 B-P
16SCCA Ent SRF3Jon McClintockSRF3231:51.704 B-Q21:51.6531:51.704 B-Q21:52.510 B-R21:52.779 B-R2+0.754 B-R2134.4 A-R130.416 B-Q232.353 B-P48.884 B-Q2
17SCCA Ent SRF3Andre PerraSRF3771:51.816 B-P1:51.8161:52.314 B-Q2111.0 B-Q230.534 B-P32.284 B-P48.998 B-P
18SCCA Ent SRF3Eric HandSRF3761:51.935 B-P1:51.7181:52.618 B-Q11:52.736 B-R21:53.362 B-R2+1.041 B-R2132.2 A-Q230.479 B-Q232.325 B-P48.914 B-P
19SCCA Ent SRF3Paul MarinoSRF3141:52.092 B-P1:51.8821:52.338 B-Q11:52.816 B-R11:53.859 B-R2+0.588 B-R2138.9 A-Q230.539 B-Q132.391 B-P48.952 B-Q1
20SCCA Ent SRF3Michael NeumeyerSRF391:52.163 A-Q21:52.0581:52.163 A-Q21:53.546 A-R11:53.921 A-R2+0.745 A-R2133.4 A-Q1, A-Q230.713 A-Q232.218 A-Q249.127 A-Q1
21SCCA Ent SRF3Graham WooddSRF3521:52.194 B-Q21:51.9591:52.194 B-Q21:52.959 B-R21:53.231 B-R2+0.687 B-R2112.4 B-Q130.631 B-Q232.483 B-Q148.845 B-Q2
22SCCA Ent SRF3Mark BallengeeSRF31971:52.334 B-Q21:51.9551:52.334 B-Q21:52.715 B-R11:53.509 B-R1+1.364 B-R1137.8 A-Q130.821 B-R132.309 B-R148.825 B-Q2
23SCCA Ent SRF3Tom BurtSRF3451:52.334 B-Q2sector data unreliable1:52.334 B-Q21:52.708 B-R11:53.274 B-R2+0.810 B-R2136.6 A-Q130.69432.31844.841
24BMW M3Wilson PowellSTU771:52.380 B-P1:52.1641:55.401 B-Q11:53.843 B-R11:54.699 B-R1+1.965 B-R1102.6 B-R130.577 B-P32.372 B-P49.215 B-P
25SCCA Ent SRF3Umberto MillettiSRF3341:52.385 B-Q11:51.7771:52.385 B-Q11:52.925 B-R11:53.355 B-R2+0.505 B-R2136.1 A-R230.406 B-Q132.405 A-Q248.966 B-R1
26SCCA Ent SRF3Lee DouglasSRF321:52.386 B-P1:51.9761:52.580 B-Q11:53.371 B-R11:54.213 B-R1+1.557 B-R1115.4 B-P30.589 B-P32.398 B-Q148.989 B-Q1
27SCCA Ent SRF3Rob PielstickerSRF3331:52.435 A-Q21:52.3941:52.435 A-Q21:53.632 A-R21:53.816 A-R1+0.453 A-R1136.8 A-P30.944 A-Q232.477 A-Q248.973 A-Q2
28SCCA Ent SRF3Paul GoudySRF31271:52.763 B-P1:52.2111:53.151 B-Q21:53.038 B-R21:53.595 B-R2+0.957 B-R2138.5 A-Q130.530 B-P32.469 B-R249.212 B-P
29SCCA Ent SRF3Maguire DickerhoofSRF3431:52.777 A-Q21:52.7771:52.777 A-Q21:53.722 A-R21:54.380 A-R2+1.053 A-R2137.6 A-Q231.056 A-Q232.628 A-Q249.093 A-Q2
30SCCA Ent SRF3Chris StrandSRF3491:52.795 B-P1:52.4751:55.168 B-Q11:56.794 B-R21:58.272 B-R2+2.172 B-R2111.6 B-P30.631 B-P32.583 B-P49.261 B-P
31SCCA Ent SRF3Tom MiserendinoSRF3151:52.801 B-P1:52.3021:53.154 B-Q21:53.280 B-R11:53.865 B-R2+0.398 B-R2130.1 A-Q130.778 B-Q232.383 B-P49.141 B-Q1
32Mazda MiataWesley MollnoSTL10, 11, 1111:52.983 B-P1:52.9831:59.582 A-Q11:59.163 A-R11:59.870 B-R2+0.510 B-R2133.4 A-Q130.838 B-P33.020 B-P49.197 B-P
33SCCA Ent SRF3Vince BalchSRF3651:53.036 B-Q21:53.0361:53.036 B-Q21:54.674 B-R11:55.749 B-R1+1.552 B-R1133.4 A-Q230.700 B-Q232.651 B-Q249.685 B-Q2
34Mazda MiataJon DaviesSTL671:53.071 B-P1:53.0711:59.281 B-Q11:59.121 B-R11:59.683 B-R1+1.145 B-R1127.3 B-P30.815 B-P32.820 B-P49.536 B-P
35SCCA Ent SRF3Jay RosenthalSRF3551:53.237 B-Q11:52.9181:53.237 B-Q11:53.706 B-R11:54.392 B-R2+0.535 B-R2136.6 A-Q131.035 B-Q132.580 B-Q149.303 B-Q2
36SCCA Ent SRF3Clayton PowersSRF3701:53.237 B-P1:52.9901:53.631 A-Q21:54.845 A-R11:55.266 A-R1+0.979 A-R1134.1 A-Q230.988 B-P32.714 A-Q249.288 B-P
37Mazda RX-8David LeCrenSTL21:53.515 B-P1:53.2532:09.464 A-Q22:11.372 A-R22:11.978 A-R2+5.025 A-R2121.0 A-Q231.217 B-P32.486 B-P49.550 B-P
38SCCA Ent SRF3John ArscottSRF3811:53.623 B-Q21:53.2881:53.623 B-Q21:54.918 B-R21:55.509 B-R2+0.858 B-R2108.7 B-Q130.895 B-Q132.634 B-Q249.759 B-Q2
39Honda S2000Rylan HazeltonSTU491:53.640 B-R11:53.1401:55.834 B-Q11:53.640 B-R11:54.534 A-R2+0.714 A-R2134.8 A-R230.582 B-R132.779 B-R149.779 A-R2
40Mazda MiataSayo HaraishiSTL341:54.120 B-P1:54.0192:08.265 B-Q12:09.190 B-R12:09.557 B-R1+0.759 B-R1105.6 B-P31.129 B-P33.359 B-P49.531 B-P
41SCCA Ent SRF3Michael MoshaySRF3161:54.242 B-R21:53.9821:54.826 B-Q21:54.242 B-R21:54.930 B-R2+1.338 B-R2129.8 A-Q231.118 B-R233.024 B-R249.840 B-R2
42Mazda MX-5Ricardo ArrudaSTL161:54.343 B-P1:54.3432:00.717 B-Q22:01.410 B-R12:02.207 B-R1+0.929 B-R1104.3 B-P31.248 B-P32.888 B-P50.207 B-P
43Mazda MX-5Gavin WardleSTL1691:54.845 A-R1sector data unreliable1:58.292 A-Q21:54.845 A-R11:59.598 A-R2+0.868 A-R2132.7 A-R28.26433.98451.822
44SCCA Ent SRF3Denny FosdickSRF3691:54.932 B-P1:54.8301:55.479 B-Q11:56.082 A-R21:57.089 A-R1+1.298 A-R1128.4 A-P31.449 B-P33.388 A-Q149.993 B-P
45Mazda MiataNick LeveroneSTL137, 371:54.963 B-Q21:54.8911:54.963 B-Q21:55.682 B-R11:56.512 B-R1+1.038 B-R1106.0 B-Q131.458 B-Q232.979 B-Q250.454 B-Q2
46SCCA Ent SRF3Doug StewartSRF3711:55.021 B-P1:54.7321:55.878 B-Q11:55.200 B-R21:55.941 B-R2+1.304 B-R2130.4 A-Q131.406 B-P33.145 B-R250.181 B-P
47Honda Civic SiJonathan LugodSTL611:56.438 B-R11:56.1281:57.331 B-Q21:56.438 B-R11:57.403 B-R1+1.528 B-R1106.8 B-P31.787 B-P33.468 B-P50.873 B-P
48BMW 330Sean LovettSTU371:56.492 A-Q21:56.4261:56.492 A-Q21:57.049 A-R21:57.605 A-R2+1.649 A-R2133.7 A-R231.816 A-Q233.669 A-Q150.941 A-Q2
49SCCA Ent SRF3Don PallaSRF337, 301:56.524 B-Q21:55.9111:56.524 B-Q21:57.682 A-R21:58.063 A-R2+0.973 A-R2125.7 A-R231.402 B-Q233.317 B-Q251.192 B-R1
50SCCA Ent SRF3David RothSRF371:56.755 A-R21:56.6071:57.730 A-Q21:56.755 A-R21:57.810 A-R2+2.186 A-R2132.7 A-P32.055 A-Q233.685 A-R250.867 A-R2
51Honda PreludeCarl YoungSTL231:56.961 B-R11:56.6311:57.917 B-Q21:56.961 B-R11:57.759 B-R1+1.599 B-R1104.5 B-Q231.994 B-R133.745 B-R150.892 B-R1
52SCCA Ent SRF3Alice KutsyySRF31111:57.255 B-P1:57.2361:59.043 B-Q11:59.139 B-R12:01.752 B-R1+6.376 B-R1104.7 B-R132.212 B-P33.871 B-P51.153 B-P
53Mazda MX-5Ryan GutileSTL1161:57.404 B-Q11:57.0041:57.404 B-Q11:57.483 B-R11:58.542 B-R1+1.371 B-R1128.4 A-Q231.829 B-R133.695 B-Q151.480 B-R1
54Mazda MiataAmy MillsSTL1141:57.757 A-Q21:57.4941:57.757 A-Q21:58.239 B-R21:58.840 B-R2+1.462 B-R2122.6 A-R232.321 B-Q233.780 A-Q251.393 A-Q2
55SCCA Ent SRF3Gary KnesevitchSRF3631:57.788 B-R21:57.0251:58.429 B-Q21:57.788 B-R21:58.928 B-R2+2.951 B-R2103.5 B-R132.046 B-R234.221 B-R150.758 B-R2
56Mazda MX-5Bryce JohnsonSTL15, 131:58.716 A-Q21:58.4191:58.716 A-Q21:59.496 A-R21:59.874 A-R2+0.878 A-R2136.6 A-Q132.248 A-Q134.104 A-Q252.067 A-Q2
57Nissan 300ZXJames SlechtaSTU751:59.183 A-Q21:59.1831:59.183 A-Q22:00.458 A-R22:01.009 A-R2+0.921 A-R2132.0 A-Q132.882 A-Q234.528 A-Q251.773 A-Q2
58Mazda MiataPatrick DrinkwineSTL1511:59.239 B-Q11:58.7541:59.239 B-Q12:00.132 B-R12:00.548 B-R1+0.505 B-R1106.6 B-P32.503 B-P34.167 B-P52.084 B-P
59Mazda MX-5Oscar JacksonSTU1611:59.707 B-R21:58.8881:59.707 B-R21:59.952 B-R2+1.112 B-R2103.9 B-R232.339 B-R234.219 B-R252.330 B-R2
60Mazda MX-5 (2015)Adrian ComstockSTL252:00.239 A-Q22:00.0152:00.239 A-Q22:00.722 A-R12:01.250 A-R2+0.672 A-R2133.0 A-R232.847 A-R234.493 A-Q252.675 A-Q2
61Mazda RX-7Michael LewisSTU322:00.248 A-R12:00.1792:00.248 A-R12:02.190 A-R2+1.431 A-R2130.4 A-R132.729 A-R134.570 A-R152.880 A-R1
62Mazda MX-5Andy ChittumSTL992:00.296 A-Q21:59.6842:00.296 A-Q22:00.787 A-R12:01.366 A-R1+1.093 A-R1132.9 A-R232.848 A-Q134.467 A-Q252.369 A-Q2
63Mazda MX-5Dale ShoemakerSTU522:01.642 B-R22:01.1762:04.115 B-Q12:01.642 B-R22:02.793 B-R2+2.442 B-R2125.9 A-Q232.956 B-R234.983 B-R253.237 B-R2
64Mazda MiataRichard JamesSTL191, 912:02.318 B-R12:01.7862:02.441 A-Q12:02.318 B-R12:03.149 B-R2+0.867 B-R2126.7 A-R132.990 B-R135.132 A-Q153.664 B-R1
65Mazda MiataTodd LaunchbaughSTL732:02.759 B-R12:02.6242:02.759 B-R12:03.974 B-R1+1.599 B-R198.5 B-R133.210 B-R135.059 B-R154.355 B-R1
66Mazda MiataAyden VaillancourSTL882:03.022 B-R12:02.3012:03.653 B-Q22:03.022 B-R12:03.841 B-R1+0.936 B-R1100.4 B-P33.072 B-P35.168 B-P54.061 B-R1
67Mazda MiataLauren Lewis >115%STL452:17.307 A-R12:16.1622:17.307 A-R12:18.705 A-R1+1.938 A-R1108.6 A-R136.821 A-R139.026 A-R11:00.315 A-R2
68Acura integraJack McEachern >115%STL212:24.310 B-Q22:22.5112:24.310 B-Q22:24.550 B-R22:32.162 B-R1+2.229 B-R177.6 B-Q138.960 B-Q141.141 B-Q21:02.410 B-R2

One row per driver and car (a driver who changed cars has a row for each). Each cell is that driver's best in that car across the selected events, with the session it was set in. Best 5-lap stint is the mean of the driver's quickest five consecutive race laps, and consistency is how far their median race lap sat behind their best in that race (small is a driver who does it every lap); both come from the race with the best stint. The fastest in each column is purple, and a car whose best lap is more than 115% of the fastest in its class is greyed (marked ">115%" beside the driver) and left out of the colour scale. Click a column to sort, a row to highlight it. Theoretical lap is the sum of the best sectors, whichever laps they came from, and never slower than the best lap (where a car's fastest laps were recorded without sector times, its best lap is used). The 115% mark is about the car's best lap only: a car whose best lap is within 115% of the fastest in its class is never marked. Greyed sectors with no theoretical lap mean the sector times on file do not add up to a believable lap. Letters refer to the events above; Q is qualifying, R a race.

Sectors

Sectors are numbered in lap order from start/finish, whatever each event's timing called them; the loop names are SCCA timing's.

By car

CarClassDriversLapQualRaceTrapS1S2S3
SCCA Ent SRF3SRF3381:50.233Caleb Shrader1:50.233Caleb Shrader1:50.825Caleb Shrader138.9Paul Marino30.136Caleb Shrader31.672Caleb Shrader44.841Tom Burt
Mazda RX-3STU11:50.913Tony Rivera1:50.913Tony Rivera1:52.737Tony Rivera135.2Tony Rivera30.415Tony Rivera32.456Tony Rivera47.999Tony Rivera
Mazda MiataSTL/STU201:51.602Whitfield Gregg1:54.963Nick Leverone1:54.845Gavin Wardle136.6Bryce Johnson8.264Gavin Wardle32.218Jared Korth48.687Whitfield Gregg
BMW M3STU11:52.380Wilson Powell1:55.401Wilson Powell1:53.843Wilson Powell102.6Wilson Powell30.577Wilson Powell32.372Wilson Powell49.215Wilson Powell
Mazda RX-8STL11:53.515David LeCren2:09.464David LeCren2:11.372David LeCren121.0David LeCren31.217David LeCren32.486David LeCren49.550David LeCren
Honda S2000STU11:53.640Rylan Hazelton1:55.834Rylan Hazelton1:53.640Rylan Hazelton134.8Rylan Hazelton30.582Rylan Hazelton32.779Rylan Hazelton49.779Rylan Hazelton
Honda Civic SiSTL11:56.438Jonathan Lugod1:57.331Jonathan Lugod1:56.438Jonathan Lugod106.8Jonathan Lugod31.787Jonathan Lugod33.468Jonathan Lugod50.873Jonathan Lugod
BMW 330STU11:56.492Sean Lovett1:56.492Sean Lovett1:57.049Sean Lovett133.7Sean Lovett31.816Sean Lovett33.669Sean Lovett50.941Sean Lovett
Honda PreludeSTL11:56.961Carl Young1:57.917Carl Young1:56.961Carl Young104.5Carl Young31.994Carl Young33.745Carl Young50.892Carl Young
Nissan 300ZXSTU11:59.183James Slechta1:59.183James Slechta2:00.458James Slechta132.0James Slechta32.882James Slechta34.528James Slechta51.773James Slechta
Mazda RX-7STU12:00.248Michael Lewis2:00.248Michael Lewis130.4Michael Lewis32.729Michael Lewis34.570Michael Lewis52.880Michael Lewis
Acura integraSTL12:24.310Jack McEachern2:24.310Jack McEachern2:24.550Jack McEachern77.6Jack McEachern38.960Jack McEachern41.141Jack McEachern1:02.410Jack McEachern

The best any driver of each car managed across the selected events, with who set it. Spellings and model years of the same car are grouped; click a row marked ▸ to see each version. Grouping is worked out from the names, so tell us if two cars are wrongly merged or split.

Rule changes between these events

Cal Club 2023 → Cal Club 2024 2023-02-24 to 2024-02-23

SRF3 Update SRF Brake Rule

#33469 from Robey Clark · Rule change · TB 23-01 (2023-01 Fastrack)

slowerSRF Renault Alliance solid front rotors banned; restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weight increased to 1100 lbs for 2009+ stock engines.

In SRF, GCR section 9.1.8.D.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall be used as delivered with no
machining of any kind. Minimum thickness 12.20mm (0.481"). The 1985 Renault Alliance solid front rotor (Reference: Bendix
PRT1318 or Centrix 121.11004) may be used on front, rear, or both axles, but each axle must be paired to the same type
rotor. The Renault Alliance solid front rotors may not be used. Rubber caliper bushings may be replaced with bronze bushings P/N
1196185 or P/N 1196185. Original caliper pistons may be replaced with vented caliper piston P/N 1196184; no other
modification allowed. Wilwood caliper with bracket universal fit P/N 800038 may be used as delivered with no modification of
any kind. Wilwood knock back spring (2.63 lbs.) P/N 800045 may be used as delivered with no modification of any kind;

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maximum of one spring per caliper."
P2 Engine Table
Spec
Line Engine Series

A specification table follows in the original; it is not shown here.

STU E&O STU NA Weight Chart.

#33737 from Eric Heinrich · Rule change · TB 23-03 (2023-03 Fastrack)

fasterSTU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs.

In STU, GCR Section 9.1.4.1.H.1. chart, Factory Engine Displacement (cc) Minimum Weight (lbs), change as follows:
"2450 2596 2595"
"2600 2860 2710"

SRF3 Update SRF Bodywork Fitment Rule

#33765 from Robey Clark · Rule change · TB 23-03 (2023-03 Fastrack)

neutralSRF3 tail sections allowed on SRFs with GEN3 airbox shimming up to 19 mm; alternate dash panel P/N 180100 or 180101 relocated in rules.

In Spec Racer Ford, GCR section 9.1.8.D.1.E, change as follows:
"j. Optional Bodywork Modification:
Viewing the tail section of the car from behind, draw a vertical line at the left and right ends of the outer vents from the bottom
edge of the bodywork up to a point two (2) inches below the crease at the lower edge of the vented panel. Make a vertical cut at
each line. The horizontal cut is to be one (1) inch below the crease at the base of the vented panel. Leave a one (1) inch radius at
each corner. Air Scoop (P/N 190000) must be installed in conjunction with rear cutout per Enterprises installation instructions.
SRF3 tail sections are allowed on SRFs. For purposes of tail section to center section fitment with the GEN3 airbox, shimming is
allowed at the rear of the center section. Shim material may be up to 19 mm (0.75") thick along the 1" upper square sidepod

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tube. Mounting location cannot be modified or added. Shim material must be securely attached, but must not be welded.
An alternate dash panel has been approved for use in Spec Racer Fords. The dash will be furnished by Enterprises only. P/N
180100 or 180101
k. Required Bodywork Modification:
A 22.5" diameter wheel arch shall be cut in each side of the tail section. Viewing the tail section from the side, draw a vertical
line at the drive axle centerline. Locate the top of the wheel arch at a point measured from the bottom edge of the tail section
9.25" vertically along the centerline. The 22.5" diameter circle intersects the bottom edge of the tail section 11.1" either side of
the centerline. The tail section may be reinforced in the forward and aft portions of the wheel arch. Dimension tolerance is +/-
0.75".
l. An alternate dash panel has been approved for use in Spec Racer Fords. The dash will be furnished by Enterprises only. P/N
180100 or 180101."

STU Alternate OEM Miata Intake Manifold

#33827 from Brandon Steinhauer · Rule change · TB 23-04 (2023-04 Fastrack)

neutralSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.

In STU Spec lines, classify Mazda BP5A as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda BP5A 1839 Chart May use engine in its entirety or specific
components from the engine.

SRF3 Update SRF Front W2 Rain Tire Part Number

#34118 from Robey Clark · Rule change · TB 23-05 (2023-05 Fastrack)

neutralSRF Hoosier front rain tyre part number changes from 46100 to 46101 P185/65R13 W2.

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Front – Hoosier P/N 46100 1 P185/65R13 W2"

STL Clarify STL table B - IT spec notes on Tires

#34187 from Austin Hilliard · Rule change · TB 23-06 (2023-05 Fastrack)

neutralSTL ITA/ITS RX7 and 1985+ ITA/ITS/ITB/ITC vehicles clarified to conform to section 9.1.4.2 tire specifications.

In STL Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Notes as follows:
ITA-spec and ITS-spec RX7: "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires & Wheels. Tires
must also conform to 9.1.4.2.Tires."
ITS, ITA, ITB, or ITC vehicles (1985- ): "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires &
Wheels. Tires must also conform to 9.1.4.2.Tires."

SRF3 Hoosier SRF Wet Front Tire Rule Update

#34189 from Robey Clark · Rule change · TB 23-06 (2023-06 Fastrack)

unclearSRF Hoosier wet front tire updated to P/N 46100 P185/60R13 H20 or W2.

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Wet:
Front – Hoosier P/N 46100 P185/60R13 H20 or W2
Rear – Hoosier P/N 46105 P205/60R13 H20 or W2
Ground clearance is 2.5" with driver as raced when P185/60R13 (H20 or W2) tires are used."

STU 2022 Toyota GR Cup for STU

#34449 from Club Racing Board · Rule change · TB 23-06 (2023-05 Fastrack)

neutralToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.

In STU Spec Lines, Toyota GR Cup (2022-), classify as follows:

A specification table follows in the original; it is not shown here.

SRF3 SRF Radiator Rule Update

#34805 from Robey Clark · Rule change · TB 23-10 (2023-10 Fastrack)

neutralSRF radiator rule clarified: P/N 480466 replaceable with Automotive P/N 1R698, CU698 or manufacturer equivalent with documentation.

In SRF, GCR section 9.1.8.D.1.V.j, change as follows:
"Radiator - Enterprises new style P/N 480465 (requires baffle P/N 480464) or P/N 480466 can be used. P/N 480466, may can be
replaced with Automotive P/N 1R698, CU698 or equivalent OEM manufacturer justified by one cross-reference chart equivalent,
as long as the size, shape, and material are the same as the original P/N. The capacity, core thickness, etc., cannot be changed
even if allowed under the above. The competitor is responsible for providing this documentation of the cross-reference P/N."

SRF3 Update SRF Rain / Brake Rule

#34706 from Robey Clark · Rule change · TB 23-09 (2023-09 Fastrack)

neutralSRF rain/brake light now requires Super Bright LEDs Inc. P/N PT-STRB-R24 with specific connector and rain light switch.

In SRF, GCR section 9.1.8.D.1.W.l, change as follows:
"A Super Bright LEDs Inc. rain / brake light comprised of a single standard trailer oval lamp, 2-1/4 inches x 6-1/2 inches, with
incandescent or LED illumination, P/N PT-STRB-R24, is required in the original roll hoop mounting location. This rule supersedes
GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No changes may be made to the original 3-pin connector on the
wiring harness. The secondary filament of the brake light assembly shall must be connected to a switch enabling its use as a rain
light."

SRF3 Update SRF Brake Light Rule v1

#34853 from Robey Clark · Rule change · TB 23-10 (2023-10 Fastrack)

neutralSRF requires Super Bright LEDs P/N PT-STRB-R24 rain/brake light with strobing capability and specific wiring.

In SRF, GCR section 9.1.8.D.1.W.l, change as follows:
"A Super Bright LEDs Inc. P/N PT-STRB-R24 (SCCA Enterprises P/N 180427A) rain / brake light, P/N PT-STRB-R24, is required in the
original roll hoop mounting location. This rule supersedes GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No
changes may be made to the original 3-pin connector on the wiring harness. An SCCA Enterprises P/N 1190503 Strobing Brake
Light Pigtail is required. The secondary filament of the brake light assembly must be connected to a switch enabling its use as
a strobing rain light. A Strobing Brake Light Kit P/N 1168003 is available, which includes the brake light and pigtail."

STL Alternate Carburetor Request for 79-85 RX7 12a

#35181 from Dan Sheppard · Rule change · TB 24-01 (2024-01 Fastrack)

unclearSTL Mazda RX-7 12A (79-85) now allows auto-type 2 bbl with 42mm choke(s) on dual-y manifold as alternate to stock Nikki 4 bbl.

In STL Table B: Alternate Vehicle and Engine Allowances, Mazda RX-7 12A (79-85), change Notes as follows:
"Street Porting of the engine only. Bridge porting, peripheral porting, and eyelash porting are prohibited. Contact SCCA National
Office for details of Street porting. Stock Nikki 4 bbl carburetor on a stock manifold only. or auto-type 2 bbl w/42mm choke(s) on
a “dual-y” manifold. Allow the standard removal of emissions related components, and allow air and fuel jets to be corrected.
Modification of the water jacket in the area of the spark plug for cooling purposes is permitted."

SRF3 SRF / SRF3 Rule Updates

#35268 from Robey Clark · Rule change · TB 24-01 (2024-01 Fastrack)

neutralSRF adds brake duct and pedal extension rules, rear shift cable clamp option, camber limit to 5.0°, radiator opening height 3.5" ±0.5", and P2 engine restrictor changes.

In SRF, GCR section 9.1.8.D.1.H, add the following:
"NO MODIFICATIONS ALLOWED. Front brake ducts are required, attached to the openings in the lower radiator baffles, any
flexible 4" duct material allowed, installed length minimum 12" maximum 36" in length. Must be securely fastened, Bracket Part
# P/N 800368 can be used. Shall Must serve no other purpose. An extension may be welded to the side of the throttle pedal to
improve heel-and-toe braking. Master cylinder casting / location must be used as delivered on P/N 180110 Pedal Mounting
support. Aeroquip style -3 braided stainless flex lines only, must attach to all brake components without modification. Brake pad
"anti-rattle" clips must be removed."
In SRF, GCR section 9.1.8.D.1.V, add the following:

Show 23 more lines

"ii. Rear SADEV shift cable aluminum two-piece style clamp may be used. The P/N WM302007A clamp must serve no other
purpose."
In SRF, GCR section 9.1.8.D.1.X.k, add the following:
"Negative camber shall must not exceed 5.0 degrees absolute maximum front and rear."
In SRF, GCR section 9.1.8.D.1.AA.b, add the following:
"2. Height of the radiator opening vertical surface 3 1/2“ +/- 1/2"."
P2 Engine Table B.1
2008 and older Stock
Suzuki, Yamaha,
Honda, BMW
38.5mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 38.5mm
Modified
Engine
950 lbs.
1005cc max
P2 Engine Table B.1
2008 and older 37mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 39mm
Stock Engine
1050 lbs.

STL ST Electric-Assisted Steering Systems

#35066 from Jose Osiris Pena · Rule change · TB 24-02 (2024-01 Fastrack)

neutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.

In GCR, Section 9.1.4.M.16., change as follows:
"Power steering may be modified in any of the following ways:
a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be
modified internally to work without pump.
b. an OEM manual steering rack for that model may be fitted
c. an electric power steering pump may be fitted
d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used
e. an OEM hydraulic-assisted steering system may be used"

STU ST Electric-Assisted Steering Systems

#35066 from Jose Osiris Pena · Rule change · TB 24-02 (2024-01 Fastrack)

neutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.

In GCR, Section 9.1.4.M.16., change as follows:
"Power steering may be modified in any of the following ways:
a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be
modified internally to work without pump.
b. an OEM manual steering rack for that model may be fitted
c. an electric power steering pump may be fitted
d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used
e. an OEM hydraulic-assisted steering system may be used"

STL BOP Adjustments

#35112 from Super Touring Committee · Rule change · TB 24-02 (2024-01 Fastrack)

fasterSTL Acura/Honda B-series and Mazda MZR restrictors reduced 2mm; minimum weights down 25–75 lbs for 1900–2000cc engines.

In GCR, 9.1.4.H.1., change as follows:
"Minimum weights for cars with normally aspirated piston engines will be determined by 1.35 lbs/cc displacement for
the installed engine (see the following table). Displacement is the factory displacement for the installed engine. For the
purpose of weight assignment, engine displacement will be rounded to the nearest 50cc (e.g., 2176cc = 2200cc and
2175cc = 2150cc)."
In GCR, 9.1.4.H.1., change Minimum Weight on Chart as follows:
Factory Engine Displacement 1900: "Effective 3-1-24: 2565 2540"
Factory Engine Displacement 1950: "Effective 3-1-24: 2633 2583"

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Factory Engine Displacement 2000: "Effective 3-1-24: 2700 2625"
In GCR, 9.1.4.H.3., change as follows:
"Front wheel drive cars with a strut type front suspension may reduce their minimum weight by 2.5 percent. Effective 3-
1-24: Front wheel drive cars with 95" or less wheelbase must add 1.25% to their minimum weight."
In STL Spec Lines, change Notes as follows:
Acura/Honda B16: "Effective 3-1-24: 53 51mm"
Acura/Honda B17: "Effective 3-1-24: 53 51mm"
Acura/Honda B18C1: "Effective 3-1-24: 53 51mm"
Acura/Honda B18C (JDM Type R), B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R):
"Effective 3-1-24:52 50mm"
Mazda MZR: "Effective 3-1-24: 52 50mm"

STL Mazda 12A

#35320 from Super Touring Committee · Rule change · TB 24-02 (2024-02 Fastrack)

slowerSTL Mazda 12A must keep 5th and 6th intake port actuators and valves, no longer allowed removal or disabling.

In STL Spec Lines, Table A, Mazda 12A, change Notes as follows:
"The 5th and 6th intake port actuators and valves may be removed or disabled."

Cal Club 2024 → Cal Club 2025 2024-02-23 to 2025-02-22

STU Letter #35397 addendum

#35453 from Aaron Fitzsimmons · Rule change · TB 24-03 (2024-03 Fastrack)

neutralSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.

In STU Spec Lines, Mini Cooper S SC with Minimum Weight 1900 and 2100, add to Notes:
"Alternate LEAP OMICRON hood scoop part # LEP-OMICRON3 is permitted."

STU S54 Drysump

#35464 from Macey Urso · Rule change · TB 24-03 (2024-03 Fastrack)

neutralSTU BMW S54 B32 OEM now permits dry sump oiling system.

In STU Spec Lines, BMW S54 B32 OEM, add to Notes as follows:
"Dry Sump oiling system permitted."

SRF3 SRF3 Alternator Pulley Update In

#36095 from Robey Clark · Rule change · TB 24-06 (2024-06 Fastrack)

fasterSRF3 alternator pulley minimum weight reduced from 12 oz to 11 oz.

SFR3, GCR section 9.1.8.D.2.H.17, change as follows:
"Alternator Pulley: P/N G902130, or P/N G902130A, or P/N G902131 (six row). 12 11 oz minimum weight."

STU RWD Turbo Disadvantage

#36255 from David Fiorelli · Rule change · TB 24-08 (2024-08 Fastrack)

fasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.

In GCR, Section 9.1.4.1.H.3 - Inlet Restrictor (mm) Minimum Weight (lbs) table, change as follows:
"RWD cars must reduce restrictor 1 mm from this table"

SRF3 Update Rain Tire Rule and Hoosier Decal Placement

#36436 from Robey Clark · Rule change · TB 24-08 (2024-08 Fastrack)

slowerSRF wet tires: P185/60R13 H20/W2 option removed; P185/65R13 W2 front now required with P205/60R13 W2 rear.

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Wet:
Front – Hoosier P/N 46100 P185/60R13 H20 or W2
Rear – Hoosier P/N 46105 P205/60R13 H20 or W2
Ground clearance is 2.5” with driver as raced when P185/60R13 (H20 or W2) tires are used.
OR
Front – Hoosier P/N 46101 P185/65R13 W2
Rear – Hoosier P/N 46105 P205/60R13 W2

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1. It is forbidden to regroove tires.
2. The use of tire warmers or cooling methods other than natural air convection or conduction is prohibited. The penalty for
violation will be the loss of qualifying times and/or the disqualification of race results.
3. Hoosier SRF/SRF3 Decal Placement:
Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose to
the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the
rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including
SCCA Enterprises."

SRF3 Update to Letter 36619 with new Hoosier Contingency Decal Info

#36624 from Robey Clark · Rule change · TB 24-09 (2024-09 Fastrack)

neutralSRF Hoosier decal requirement reduced from four decals in specific locations to three decals with simpler placement rules.

In SRF, GCR section 9.1.8.D.1.X.f.3, change as follows:
"Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose
to the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the
rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including
SCCA Enterprises Per Hoosier's contingency program, three (3) decals are required to qualify for contingency awards. One (1)
decal must be located on each side of the car and one (1) decal must be visible on the front."

SRF3 Update SRF3 Air Filter Rule

#36681 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

unclearSRF3 air filter rule removes K&N RC-9160 option, leaving only P/N WM301020 allowed.

In SRF, GCR section 9.1.8.D.2.H.23, change as follows:
"Air Filter: P/N WM301020 or K&N RC-9160"

SRF3 Update SRF Brake Rotor Thickness

#36687 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

slowerSRF brake rotor minimum thickness increases from 12.20mm to 13.25mm, Wilwood vented rotor P/N 800065.

In SRF, GCR section 9.1.8.D.1.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall must be used as delivered with
no machining of any kind. Minimum thickness 12.20mm (0.481”) 13.25mm (0.522”)."

SRF3 Hoosier Tire Decal Placement

#36739 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

neutralSRF3 Hoosier logo placement changes from four decals to three decals in different locations.

In SRF, GCR section 9.1.8.D.2.B, change as follows:
"Mandatory identification: "SRF3" near the side car numbers. "Hoosier" logo (4) on both sides front lower outer corners of the
nose and each side of the tail. Three (3) "Hoosier" logos, one (1) on each side of the car and one (1) on the center front of the car."

STU R53 15% Pulley Request

#36980 from Aaron Fitzsimmons · Rule change · TB 24-11 (2024-11 Fastrack)

slowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.

In STU Spec Lines, Mini Cooper S SC, add to notes:
1900: "Stock supercharger pulley. 2.565 diameter."
2100: "JCW Pulley permitted. May run a 2.285 diameter pulley."

STL Request to Remove Miata Hubs from General category

#37138 from Christopher Childs · Rule change · TB 24-12 (2024-12 Fastrack)

neutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.

In GCR, Section 9.1.4.M.18., change as follows:
"18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda
Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1."

STU Request to Remove Miata Hubs from General category

#37138 from Christopher Childs · Rule change · TB 24-12 (2024-12 Fastrack)

neutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.

In GCR, Section 9.1.4.M.18., change as follows:
"18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda
Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1."

STU BMW N54/N55 Engine Allowance

#37146 from Martin Sarukhanyan · Rule change · TB 24-12 (2024-12 Fastrack)

slowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.

"Turbo inlet restrictors designed per GCR Appendix F Technical Glossary definition of “Turbo Inlet Restrictor” may be required;
see table 9.1.4.1.H.h.2 3. Swapping of turbochargers between engine makes and models is prohibited. Supercharged cars may be
approved on a case-by-case basis; twin turbo engines are allowed on a case-by-case basis only. Contact the Road Racing
Technical Office for details. Twin turbo engines may be converted to single turbo using one of the allowed alternate turbos (see
9.1.4.1.H.3 2). Aftermarket turbocharger and supercharger kits will be allowed on a case-by-case basis.

STU Audi 1.8t Wagon STU Table B

#36685 from Mike McLaughlin · Rule change · TB 25-01 (2025-01 Fastrack)

fasterSTU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, delete Audi/VW 1.8 Turbo in its entirety.
In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, Porsche 944 w/Max Displacement 1800, change as
follows:
Weight: "3050 Chart"
Notes: "VW/Audi 1.8L 35mm turbo engine permittedinlet restrictor required."

STU Merger GT3 to STU

#37486 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

neutralSTU-GT3 reclassified as STU-GT3U effective January 1, 2026.

In STU, Table C, change STU-GT3 charge as follows:
"(Effective January 1, 2026) TABLE C: STU-GT3U"

STU GT3 TCR Tire allowance

#37494 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

slowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.

In STU, Table C, GT3 TCR, add to Notes the following:
"May run DOT approved tire with maximum section width of 275 with 100 pound weight adder. May not run A compound with
275."

Cal Club 2025 → Cal Club 2026 2025-02-22 to 2026-02-21

STU BMW N54/N55 Engine Allowance Follow Up

#37447 from Martin Sarukhanyan · Rule change · TB 25-03 (2025-03 Fastrack)

neutralSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.

In STU Spec Lines, Table A, classify BMW N54/N55 as follows:
STU Maximum Displacement
(cc's) Minimum Weight Notes
BMW N54/N55 3.0 Chart +3% (DI) Short blocks, heads, and intakes may be
freely swapped within these engine
designations. N54 twin turbo not allowed

STU STU Mini Cooper pulley size clarification re: letter #36980

#37717 from Aaron Fitzsimmons · Rule change · TB 25-03 (2025-03 Fastrack)

fasterSTU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185.

In STU Spec Lines, Mini Cooper S SC, add to notes:
2100: "May run a 2.285 2.185 diameter pulley."

STU Question About a Weight Modifier

#37782 from Peter St Pierre · Rule change · TB 25-03 (2025-03 Fastrack)

fasterSTU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A.

In STU Spec Lines, Table A, Honda K20C1 Turbo I4, add to Notes the following:
"The 3% DI weight adder does not need to be applied."

STU Increase Minimum Weight

#37919 from Club Racing Board · Rule change · TB 25-03 (2025-03 Fastrack)

slowerSTU GT3U minimum weight increases 150 to 250 pounds.

In STU Spec Lines, Table C: STU-GT3U, change Minimum Weight as follows:
"150 250 pounds"

SRF3 Driver Safety & Comfort

#37966 from Robey Clark · Rule change · TB 25-04 (2025-04 Fastrack)

neutralSRF drivers with disabilities may modify seat and controls for safety and comfort with approval and logbook notation.

In SRF, GCR section 9.1.8.D.1.D, add the following:
"f. Driver Safety and Comfort modifications to seat and controls for drivers with disabilities may be made only by approval. These
modifications must be reported to SCCA Enterprises and noted in the car logbook. The modifications are approved only for the
noted driver with disabilities. If the car is used by or sold to another driver, it must be returned to the previous standard
configuration."

SRF3 Update SADEV transmission specs

#37992 from Club Racing Board · Rule change · TB 25-04 (2025-04 Fastrack)

neutralSRF SADEV-SRF3 6-speed sequential transmission gear ratios wording clarified, effective 2025-04-01.

In SRF, GCR section 9.1.8.D.2.K, change as follows:
"OR
SADEV-SRF3 6-Speed Sequential (beginning from Oct. 4, 2021 onward):
1st 12-36 3.0000 : 1
2nd 15-31 2.0667 : 1
3rd 18-28 1.5556 : 1
4th 22-28 1.2727 : 1
5th 24-26 1.0833 : 1

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6th 25-23 0.9200 : 1
Final Drive Ratio: 15-48 3.20"

STL E&O: SMX Allowance in STL

#37945 from Greg Amy · Rule change · TB 25-05 (2025-05 Fastrack)

unclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1 instead of 2500 lbs; spec components removed, only alternative tires allowed.

In STL Spec Lines, Table B, Mazda Spec MX5 Challenge, change as follows:
Minimum Weight: "2500 See 9.1.7.1."
Notes: "Mazda MX5 Challenge car must utilize the following components: Roush CNC cylinder head 0000-01-5300,Mahle
standard or +0.005 0000-01-5310, OEM camshaft, 11:1 compression ratio, header 0000-06-5407-NC, exhaust 0000-06-5427-NC,
cold air intake 0000- 06-5150-KT, ECU flash 0000-01-5379, Pagid front brake pads 0000-03-5104-SP or endurance pads 0000-03-
5104-EN, Pagid rear brake pads 0000-03-5114-SP or endurance pads 0000-03-5114-EN, Penske front shock 0000-04-5291-SA,
Penske rear shock 0000-04-5292-SA, Penske rear mount kit 0000-04-5358, Front mount kit 0000-04-5359, Front offset bushing
0000-04-5407-NC, Eibach front springs 0000-04-9700-08, Eibach rear springs 0000-04-9400-07, Eibach helper springs 0000-04-

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9926, Eibach front sway bar 0000-04-5306-FT, Eibach rear sway bar 0000-04-5306-RR, Interior finish panels 0000-07-5822, C&R
radiator/oil cooler assembly 0000-01-5504-CR, Oil cooler adapter and lines 0000-01-5511-KT, ACT clutch 0000-02-5004-G6,
wheels 17x8 #0000-04-5706-GM, # 0000- 04-5706-SL, and Toyo RR 235-40-17 dry, Toyo RA1 235-40-17 wet. Alternative tires on
17x7 wheels per STL rules. No other Super Touring modifications or allowances permitted except as noted in this spec line. Must
conform completely to GCR 9.1.7.1, except alternative tires (only) per STL regs allowed."

Applies to Mazda Miata on this page: Jared Korth, Ricardo Arruda, Gavin Wardle, Ryan Gutile, Bryce Johnson, Andy Chittum, Adrian Comstock

STU Wheel Size Inconsistency

#38018 from David Fiorelli · Rule change · TB 25-05 (2025-05 Fastrack)

neutralSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.

In GCR, Section 9.1.4.1.F.1., change as follows:
"Wheels may not exceed 18 inches in diameter. or 8.0 inches in width for vehicles 2950 lbs. and under minimum allowed race
weight. Vehicles over 2850 minimum allowed race weight may use a 9 inch wide wheel. Cars equal to or less than 2,850 lbs.
minimum allowed race weight may not use wheels wider than 8 inches. Cars greater than 2,850 lbs. minimum allowed race
weight may not use wheels wider than 9 inches."

STU Table C: STU-GT3U Clarification

#38268 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

fasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.

In STU Spec Line, Table C: STU-GT3U, change as follows:
Minimum Weight: “Current GT3 race weight plus 250 225 pounds”
Notes: "DOT approved tire with maximum section width of 245. GT3 cars base wheel is a maximum of 15”x9”. 18”x9” wheels
allowd with a 3% weight addition. GT3 cars utilizing 15”x7” wheels are limited to a maximum section width of 225 with a 25
pound weight reduction"
"All GT3U (Majors and Runoffs) cars using up to 15"x7" wheels limited to 225 section width tires shall run at current GT3 race
weight plus 225lbs. All Gt3U cars shall run a DOT approved tire with a maximum section width of 245. GT3U cars are allowed
optional 15"x9" wheels with a 1.5% weight addition or up to 18"x9" wheels with a 3.0% weight addition to the total weight

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including the 225 lbs."

STU 2.8-3.2L N/A Engine Allowances

#38007 from Ben Slechta · Rule change · TB 25-07 (2025-07 Fastrack)

unclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.

In GCR, Section 9.1.4.G.1, add the following:
"A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."

STU 2006-2015 Mazda Miata Intake Manifold

#38422 from German Candelario Candelario · Rule change · TB 25-07 (2025-07 Fastrack)

neutralSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.

In STU, Table A, Mazda MZR (LF, L3, L5), change Notes as follows:
"May use Goodwin Part # 61-2510 or Gato Performance Part #31972 Intake manifold . "

STU Requesting Approval of the JDM Honda h23a

#38489 from Eric Fiest · Rule change · TB 25-07 (2025-07 Fastrack)

neutralSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.

In STU, Table B, classify Honda JDM H23a as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Honda JDM H23a 2259 Chart Must meet all ST engine regulations.

STU STU-TCR Adjustments

#38723 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

slowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.

In STU Spec Lines, Table C: STU-GT3U, GT3-TCR, change as follows: Remove the current TCR spec line and add the TCR spec lines
from GT3 that are being removed, adding the below to the notes.
"DOT approved tire with maximum section width of 245. May run DOT approved tire with maximum section width of 275 with
100 150 pound weight adder. May not run A-compound with 275. STU-TCR spitters and side valance must comply with
9.1.4.D.3.f. STU-TCR chassis ride height must comply with 9.1.4.1.A.1."

STL Lotus Weight Reduction

#38772 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

fasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.

In 9.1.2. GT2/ST Spec Lines, Lotus Evora GT4, change Weight as follows:
"2750 2700"
In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise Cup R: "2300 2250"
Lotus Elise SC/ Lotus Exige SC: "2300 2550
2500 2450"

STU Lotus Weight Reduction

#38772 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

fasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.

In 9.1.2. GT2/ST Spec Lines, Lotus Evora GT4, change Weight as follows:
"2750 2700"
In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise Cup R: "2300 2250"
Lotus Elise SC/ Lotus Exige SC: "2300 2550
2500 2450"

SRF3 SRF Rule Updates

#38853 from Robey Clark · Rule change · TB 25-09 (2025-09 Fastrack)

neutralSRF3 brakes restructured: Hawk Blue 801993 pads, Wilwood 800065 rotors only; adds Girling 880358, Wilwood 880357, Tilton 880360 master cylinders.

Effective 9/1/25 in SRF, GCR section 9.1.8.D.1.V.ff, add the following:
"SRF3 Oil Cooler, P/N G480503 may be used as mounted per the GEN3 Assembly Manual. No fan permitted for SRF. HD Oil
Cooler kit P/N G1148500 may be used as mounted per the GEN3 Conversion Manual."
Effective 9/1/25 in SRF, GCR section 9.1.8.D.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 must be used as delivered with no
machining of any kind. Minimum thickness 13.25mm (0.522”). The Renault Alliance solid front rotors may not be used. Rubber
caliper bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185. Original caliper pistons may be replaced
with vented caliper piston P/N 1196184; no other modification allowed. Wilwood caliper with bracket universal fit P/N 800038

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may be used as delivered with no modification of any kind. Wilwood knock back spring (2.63 lbs.) P/N 800045 may be used as
delivered with no modification of any kind; maximum of one spring per caliper.
1. Hawk Blue pads P/N 801993 only
2. Wilwood Vented Rotor P/N 800065 only, as delivered, with no machining of any kind. Minimum thickness 13.25mm (0.522")
3. Wilwood universal caliper Kit P/N 1180008 as delivered, caliper only P/N 800038; Wilwood knock back spring P/N 800045
may be used as delivered, with no machining of any kind, and only one spring per caliper
4. Renault caliper rubber bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185A
5. Renault caliper piston may be replaced with P/N 1196184 vented piston as delivered, with no machining of any kind
6. Girling .750" Master Cylinder P/N 880358 as delivered, with no machining of any kind
7. Wilwood .750" Master Cylinder P/N 880357 as delivered, with no machining of any kind
8. Tilton .750" Master Cylinder P/N 880360 as delivered, with no machining of any kind"

STU Lotus Weight Reduction E&O

#38919 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

fasterSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.

In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise SC/ Lotus Exige SC: "2450 2250"

SRF3 Add HD Oil Cooler

#38979 from Robey Clark · Rule change · TB 25-10 (2025-10 Fastrack)

neutralSRF3 adds HD Oil Cooler P/N G1148500 as alternative to standard cooler P/N G480503.

In SRF, GCR section 9.1.8.D.1.V.ff, change as follows:
"SRF3 Oil Cooler, P/N G480503 or HD Oil Cooler P/N G1148500 may be used as mounted per the GEN3 Assembly Manual. No fan
permitted for SRF. HD Oil Cooler kit P/N G1148500 may be used as mounted per the GEN3 Conversion Manual."

STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ

#38746 from William Rori · Rule change · TB 25-09 (2025-09 Fastrack)

slowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, Honda K24, change Weight as follows:
"(Effective 11/1/2025) Chart + 2%"

STU Turbo Inlet Restrictor Table

#38961 from John Weisberg · Rule change · TB 25-12 (2025-12 Fastrack)

slowerSTU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985).

In GCR, Section 9.1.4.H.3, change chart as follows:

A specification table follows in the original; it is not shown here.

STU 275 Tire Rule

#38983 from Peter Federlin · Rule change · TB 25-12 (2025-12 Fastrack)

slowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.

In GCR, Section 9.1.4.G.1., change as follows:
"A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."

STU STU Honda Engine weight penalty

#39375 from Super Touring Committee · Rule change · TB 25-12 (2025-12 Fastrack)

fasterSTU Honda K20 and K24 engines lose 2% minimum weight penalty.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Minimum Weight as follows:
Honda K20: "Chart + 2%"
Honda K24: "Chart + 2%"

STU Request for Permission on Aftermarket Turbo Kit and Intake

#39529 from John Grim · Rule change · TB 26-01 (2026-01 Fastrack)

fasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.

In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, Mazda MZR (LF, L3, L5), change Notes as follows:
"Short blocks, heads, and intakes may be freely swapped within these engine designations. May use Goodwin Part # 61-
2510 or, Gato Performance Part #31972 or Jack Spania Racing 70 mm sheet-metal aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-A17."
In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, classify Mazda MZR (LF, L3, L5) Turbo as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda MZR (LF, L3,
L5) Turbo

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Varies Chart Short blocks, heads, and intakes may be freely
swapped within these engine designations. May
use Jack Spania Racing 70 mm sheet-metal
aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-
A17. Fab9 Tuning bottom-mount turbo kit
approved with one of the STU approved Turbos.

STL Weight adjustment for STL

#39579 from Super Touring Committee · Rule change · TB 26-01 (2026-01 Fastrack)

slowerSTL minimum weights increase across all classes, 1300 cc gains 195 lbs to 1950, up to 1850 cc at 2500.

In GCR, Section 9.1.4.2.H.1. change Minimum Weight on chart as follows:

A specification table follows in the original; it is not shown here.

What the rules allowed changed as listed; this does not say what any particular car ran.