A NEW CHAPTER OF NORCAL ENDURANCE RACING

SPEEDSF ENDURANCE SERIES

Open Rules, Close Racing!

2025 Schedule & Registration:

Race 1: Mar 8-9 Buttonwillow Circuit

Race 2: May 10-11 Sonoma Raceway

Race 3: Aug 31 -Sep 1 Thunderhill East

Race 4: Nov 8-9 Sonoma Raceway

Aug 31st - Sept 1 Thunderhill Schedule

Rules & Classification:

Entry Fee:

  • Pricing

    • $400-600

    • Depends on location

Contingency Prizes:

  • Free Maxxis VR2 Tire

    • 1st, 2nd & 3rd place teams in class

    • Team must run Maxxis tires to qualify for contingency prizes (RC1, VR1 or VR2)

    • See Maxxis Contingency Program

  • Speed SF track credits

How we set race pace

After the qualifying session, a delta lap time will be set for each class. If a vehicle exceeds this pre-set lap time , a black flag penalty will be issued. This rule ensures fair competition and maintains the spirit of endurance racing.

Black Flag Penalties for Delta Lap Time Violations

  • First Offense: Warning only if the exceeded laptime is within 1 sec. More than 1 sec will result in a drive-thru penalty.

  • Second Offense: Drive-thru penalty.

  • Third Offense: 3-minute hold in the penalty box.

  • Fourth Offense: 5-minute hold in the penalty box.

  • Fifth Offense: Move up a class. If the highest class has been reached (Group A), the team will be disqualified from the race.

Mandatory Pit Stop

1 Minimum pit stop required. 

  • Pit stops will only be performed at the hot pit, which requires a 5-minute pit time. (In and out of the paddock/hot pit)

  • Refuel must be performed in the hot pit.

  • Tire change is allowed after refueling.

  • A timer will be placed on every vehicle during the pit stop.

Classification

Our classes are classified by laptime. Below are the examples for Thunderhill Raceway 3 miles bypass configuration:

  • Group A - Target lap time: 1:54 - 1:59*

    • Example: M3, Corvette, Cayman, etc

  • Group B - Target lap time: 2'00 - 2'05*

    • Example: 350z, S2000, Spec E46, Mustang, Boxster, etc

  • Group C - Target lap time: 2'06+*

    • Example: Miata, E30, IS300, 944, E36 325i/328i, etc

*Actual Classing will be determined by historical data and the build reports supplied by teams after the qualifying session