A NEW CHAPTER OF NORCAL ENDURANCE RACING

SPEEDSF ENDURANCE SERIES

2025 Schedule:

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

Rules & Classification:

Entry Fee:

  • Pricing

    • Early bird $450

    • Regular $550 

    • Late $650

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: Drive-through penalty (warning for exceeding the delta time).

  • Second Offense: 2-minute hold in the penalty box.

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

  • Fourth Offense: Disqualification from the race, with removal from competition for the remainder of the event.

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.