Enduro Rules

2018 Irwindale Speedway Enduro Rules *Revised 09/30/2018* (shown in blue)


NOTE: These Rules apply to the November 3, 2018 Enduro Nationals. They will also be used as a guide for the establishment of the 2019-2020 Enduro Division Rules.


Irwindale Speedway reserves the right to amend these rules. It is the responsibility of each competitor to read and understand the rules. If there is a dispute regarding the meaning or application of these rules, the decision of Irwindale Speedway Officials shall prevail. If these rules do not specifically state that you can alter, change, or modify the car or car part, it should be considered a violation of the rules. No car or car part is deemed to have been approved by passing through prior technical inspections.



Open to any 1980 to 2004 American or Foreign 2 or 4 door hardtop front wheel drive model cars.



All cars must maintain stock OEM body for year, make and model. No Carbon fiber or Kevlar parts. Cars equipped with a sun/moon roof must have the glass and mechanism removed and replaced with a solid single piece of minimum 18-gage metal panel held in place with a minimum of eight (8) rivets, screws or bolts. A minimum of two (2) pins per hood and two (2) pins per deck lid. Hood and deck lid latch may be removed. Hood and deck lid hinges may be used. Full stock steel floorboards and firewalls required in stock location. A rear aerodynamic device (rear spoiler) may be used.



Stock front and rear bumpers are required. All bumper covers must be complete and neat appearing. Headlights, marker lights and tail lights must be removed.


A windshield is mandatory. The windshield may be replaced with one made of minimum 1/8-inch polycarbonate sheeting (Lexan) or a steel mesh screen. All other windows must be removed. Two (2) windshield supports between the dash board and the inner structure of the roof are mandatory for cars with a Lexan windshield or mesh windscreen. Driver side window net is required on all cars. Window net must be equipped with a quick-release device on the top left corner. An interior rearview mirror is mandatory. A driver’s side mirror can be used but must not extend past the body of the car.



Steel doors only. Doors must welded or be bolted shut using a minimum of two (2) 3/8-inch bolts and a 1-inch by 6-inch steel strap. Stock steel fenders and quarter panels only.



A roll cage built to the following guidelines is mandatory: Constructed of magnetic steel tubing with a minimum outside diameter of 1 ½-inchs and a minimum wall thickness of .090-inches. All welds on the roll cage must be of good quality. Bolted roll cage kits can be used but must be approved by Irwindale Speedway. The design of the cage is: three (3) door bars on both sides. Door bars can be straight. A left and right A-post bar located below the A-post of the car near the dashboard must be connected to the door bars. The A-post bar can be a continuation of the upper door bar. Both of the A-post bars must be welded and/or bolted to the car using 2-inch by 2-inch by 4-inch 3/16-inch thick steel angle. The main roll bar hoop must be welded to the door bars on both sides. The main roll cage hoop must be welded and/or bolted to the car using 2-inch by 2-inch by 4-inch 3/16-inch thick steel angle. A horizontal cross bar must be welded each side of the main roll bar hoop. The main roll bar hoop must also be welded to a right side and left side angled rear facing down bars. Both of these bars must be welded or bolted to the car using 2-inch by 2-inch by 4-inch 3/16-inch thick steel angle. All of the angle attachments that are bolted to the car must be secured using a minimum of four (4) 3/8-inch grade 8 bolts at each location. The two lower A-post bars must be welded to the other using a single one-piece bar that runs from the left side to the right side of the car just below the steering column. Roll bar padding must be used at any point where driver may make contact. The door bars must be covered with a 1/8” thick steel plate, top to bottom, from front A-post bar to the rear uprights of the main roll bar hoop. The plate must be stitch-welded to outside door bars. Stock frames only for year make and model. No modifications to the frame allowed. The addition of a front strut tower connector bar in the engine compartment is NOT Allowed. The addition of a rear strut tower connector bar in the trunk or inside the passenger area of the car is allowed. Any device that in the judgment of Irwindale Officials is used to stiffen the chassis or frame is beyond what is allowed in these rules is NOT Allowed.



Minimum weight 2500lbs without driver. Car must be balanced for right and left side weight percentage within 1% without driver. Minimum wheelbase 90-inches. Maximum wheelbase of 107-inches. Cars must remain as factory produced with regards to wheelbase. All added weight (lead) must be securely fastened to the car using (2) 1/2” grade 8 bolts. Added weight attached to the floorboard of the car must also use a minimum of 1/8-inch steel strap between the floor of the car and the nut or bolt head. All added weight must be painted white and have car number printed on it. No added weight is to be mounted behind the rear axle and no further forward than the front firewall.



The engine must be completely stock for make and model of car. All engines must be mass-produced for the US market. No special performance options will be allowed. 4-cylinder naturally aspirated engines with a maximum displacement of 2.5 liters (2500cc). No turbo-chargers or supercharger allowed. Engines may be rebuilt or repaired to manufacturers and industry standards approved by Irwindale Speedway Officials. Other than parts used to rebuild or repair an engine to the approved standards, no aftermarket parts are allowed in or on the engine. Parts and components used for an approved repair or rebuild to the engine must be of the same design and characteristics as the part(s) that are being replaced. Stock fuel injection or carburetor for make and model car only. Stock head only. A stock head will be characterized as a cylinder head which was offered as standard equipment with no performance advantage and stock for make and model. Stock blocks only with no modifications. Stock type timing chain or belt only. The cam(s) must remain stock. Stock unmodified OEM intake manifold only. Exhaust manifold or header must be approved by Irwindale Speedway Officials. Paper or gauze air filter/air filter elements are allowed. A washable air filter element ok. Aftermarket air tubes that relocate the air filter and housing inside the engine compartment are allowed but must be approved by Irwindale Speedway Officials. The engine must be located in the stock location. All engine mounts must be securely bolted.



A one (1) quart minimum water overflow catch can unit required. Must be mounted in engine compartment. No anti-freeze, coolant or similar products. Radiator must be in the stock location. Mechanical or electric fans are approved.



Stock ignition only. Stock ECU, ECM and PCM for year, make and model only. No performance aftermarket ECU/ECM, PCM distributors, ignition components (except spark plugs and plug wires). All cars should be equipped with a master electrical switch located in the cockpit of the car. The switch must be clearly marked “OFF” and within reach of the driver and safety crew from the left or right side of the car. The switch must shut off car. Batteries must be securely mounted in the car in a sealed battery box. Except for those that are original equipment of the car being used, the use data loggers capable of storing information, timing retard controls, GPS devices, torque control or electronic traction control devices will not be allowed.



Any Stock OEM exhaust system allowed. The muffler and catalytic converter may be removed. The exhaust must exit behind the driver. Cars must not exceed 90db @100 feet.



Stock manual or automatic transmission and transmission components (clutch, flywheel, pressure plate, etc.) for make and model being used. No modifications to the transmission or its components. All gears must be operable including reverse. No mechanical limited slip differentials. No traction aid devices.



The only modifications allowed to the suspension are those detailed below. All other suspension components must remain as design and unaltered from the original for the make and model of car being used. No widening of the suspension. Any OEM type steel non-adjustable, non-rebuildable, factory sealed (welded) shock or strut that fits the stock mounts in the stock location may be used. Strut and shock ends must be OEM original. Stock type springs for make. All springs must be approved by Irwindale Speedway before being used in competition. The spring location and mounting may not be altered in any way. No adjustable spring mounts. The maximum camber adjustment allowed front or rear is 2 degrees.



With the exception of the brake pads and fluid, all other brake system components must remain stock for make and model car being used. The brake pads may be replaced with high-performance pads.



Stock steel OEM for make and model steering components only.



Pump fuel only. No additives, octane boost or blending of fuels. The only oxygenates present in the fuel cannot exceed the amount common to pump gas. The gas tank must remain in the stock location.



Steel or aluminum wheels only. The maximum wheel width is 7-inches. The maximum wheel diameter is 16-inches. Wheels may be any off-set but the offset must match for all four wheels. All tires used in competition must be submitted to Irwindale Speedway Officials for approval. The lowest treadwear rating for an approved tire is 200. The treadwear rating must be clearly visible on the sidewall of the tire. The maximum purchase price for any single tire used in competition is $135 The maximum tread width of a single tire is 7.5-inches. Irwindale Speedway reserves the right to mandate a track tire that must be used by all competitors.



For all safety equipment, it is the responsibility of the driver, to ensure that all safety equipment is correctly installed, maintained, and properly used. The safety equipment manufacturer‘s installation and use guidelines must be used at all times to ensure the proper use and maintenance of all safety equipment.



A minimum five-point safety harness, manufactured to the SFI standard is mandatory. All belts shall be attached using minimum 3/8 grade 8 hardware or the mounting hardware supplied by the seat belt manufacturer. Wrap around shoulder belts ok. Must be mounted per manufacturer guidelines. Shoulder belts must remain stationary on the bar and not move allowing the belts to slip off of the driver’s shoulders. Safety harnesses/seat belts must not show wear. Torn or frayed belts must be replaced.



A helmet meeting the Snell SA2010 or SA2015 standard is required. An SFI approved head and neck restraint device is recommended.



A fire suit meeting the SFI 3.2/A1 standard at a minimum is mandatory at all times. Gloves are mandatory. Approved racing gloves, racing shoes and fire-resistant undergarments are recommended.



A fire extinguisher installed in the car within driver’s reach is recommended. Steel mounts only.



A number with a minimum of height of 18-inches on the roof and both sides of the car must be used. Side numbers may be located anywhere rearward of the front fender. All numbers must be of a contrasting color of the car. Roof numbers face toward right side of the car. Numbers are assigned by Irwindale Speedway. Numbers may be one to three digits. Double and three-digit numbers must not overlap. No duplication of numbers, additional letters such as “Y” and N” are not to be used. The letter “X” shall be deemed to represent the number 10. Advertising or names on the windshield is not permitted except those that are an approved sponsor of the Irwindale Speedway Enduro Division. Advertising, logos or slogans that are deemed by Irwindale Speedway to be unsuitable or offensive, will not be allowed.


All cars must be equipped with a one-way radio monitoring the Irwindale Speedway race control frequency. All drivers must be able to monitor all communications from race control at all times while their car is on the track during an event.