Unlimited open wheel vehicles with limited engine.

Last Updated April 10, 2024

DEFINITION

Unlimited 4 wheel single and two seat vehicles with a limited engine.

No production bodied vehicles allowed in this class.

GENERAL REGULATIONS

Entrants in this class shall comply with all applicable general regulations.

TECHNICAL REGULATIONS

This class is an open class and all components will be considered open unless restricted herein.

NOTE: The TR abbreviations listed under this class (I.E. TR1 HELMETS) refer to TR cross reference listings in the front of this book. These TR cross-referenced listings are part of the class rules. Where a conflict occurs between the TR cross-referenced listing and a rule contained under this class, the rule contained under this class takes priority.

SAFETY EQUIPMENT

TR1 HELMETS

TR2 PROTECTIVE CLOTHING

TR3 EYE PROTECTION and DENTURES

TR4 HEAD AND NECK RESTRAINTS

TR5 FIRST AID KIT

TR6 EMERGENCY SIGNALING DEVICES

TR7 HORNS

TR8 REFLECTORS

TR9 FIRE SUPPRESSION EQUIPMENT

TR10 SURVIVAL SUPPLIES

SUSPENSION COMPONENTS

TR11 SHOCK ABSORBERS and BUMP STOPS

TR12 SECONDARY SUSPENSION

TR13 WHEELS and TIRES

TR14 FASTENERS

STEERING and BRAKE COMPONENTS

TR15 STEERING

TR16 BRAKES

ELECTRICAL SYSTEM

TR17 IGNITION

TR18 BATTERIES

TR19 LIGHTS

TR20 STARTERS

FUEL SYSTEM

TR21 FUEL

TR22 FUEL TANKS

TR23 FUEL FILLERS LINES, VENTS, and CAPS

Fuel cell mandatory.

ENGINE, TRANSMISSION and DRIVELINES

TR24 ENGINE and ENGINE DISPLACEMENT

Any engine may be used providing:

1. It is a design that has been series produced in quantities of 5,000 units or more and is readily available to the general public in the U.S.A.
2. It did not displace more than 2500cc in the stock form.
3. It retains a maximum of four (4) valves per cylinder. Has no more than four (4) cylinders.
4. Single seat vehicles must not displace more than:
   1. 1800cc water-cooled eight valve with a single two-barrel carburetor.
   2. 1750cc water-cooled sixteen valve with a single two-barrel carburetor or stock fuel injection. Max throttle body size 58.5mm.
   3. 2200cc four cylinder, push rod, air cooled with one (1) or two (2) carburetors, or stock fuel injection.
   4. Stock production GM Eco-Tech engine. 2.2L or 2.4L. Engine must be sealed by an approved Unlimited Off-Road Racing engine builder.
   5. Ford 2.0L 14-DI-TIVCT engine. Engine must be sealed by an approved Unlimited Off-Road Racing engine builder.
5. Two seat vehicles must not displace more than:
   1. 1900cc water-cooled eight valve with a single two-barrel carburetor.
   2. 1850 water-cooled sixteen valve with a single two-barrel carburetor or stock fuel injection. Max throttle body size 58.5mm.
   3. 2400cc four cylinder, push rod, air cooled with one (1) or two (2) carburetors, or stock fuel injection.
   4. Stock production GM Eco-Tech engine. 2.2L or 2.4L. Engine must be sealed by an approved Unlimited Off-Road Racing engine builder.
   5. Ford 2.0L 14-DI-TIVCT engine. Engine must be sealed by an approved Unlimited Off-Road Racing engine builder.
6. It is not a rotary-piston engine.

Single and two seat vehicles may use one carburetor providing:

1. It retains a maximum of two (2) ventures per carburetor.
2. Maximum allowable venturi size is 42mm.
3. Carburetor(s) must be of the production automotive type.
4. Four cylinder, push rod, air cooled motors may use two (2) carburetors.

Fuel injection is stock with the following restrictions:

1. Intake manifold must remain as delivered by the manufacture. It will retain it’s stock shape, size, and configuration. No porting or other modifications. Ports may be matched to heads, but matching may not exceed .250 inches (1/4 inch) deep. Manifold must be the unit that was installed and delivered on the engine by the original manufacture. Only U.S.A. delivery fuel injection is allowed. Manifold must be installed and sold on production vehicles that are sold for highway use in the U.S.A. and be readily available to the general public.
2. Throttle body must be production (OEM) type readily available to the general public in the U.S.A.

If Unlimited Off-Road Racing at anytime during the racing season determines that any particular brand or make of engine has an advantage, we may equalize that engine either by a reduction in cc’s or the use of a restrictor. These changes may be required during the racing season.

TR25 ENGINE REPLACEMENT

TR26 TRANSMISSION

TR27 THROTTLES

TR28 EXHAUST

TR29 DRIVE SHAFTS

TR30 FLYWHEEL SHIELDS

TR31 FLUID COOLERS

TR32 AUXILIARY EQUIPMENT

TR33 SUPERCHARGERS and TURBOCHARGERS

VEHICLE SAFETY EQUIPMENT

TR34 ROLL CAGES

TR35 SAFETY HARNESS

TR36 SAFETY NETS

TR37 SEATING

GENERAL VEHICLE COMPONENTS

TR38 DRIVERS COMPARTMENT

TR39 DOORS AND LATCHES

TR40 FIREWALLS

TR41 BALLAST

TR42 WEIGHT

TR43 FLOORBOARDS

TR44 BUMPERS and HAZARDOUS PROTRUSIONS

TR45 MIRRORS

TR46 SKID PLATES

TR47 STORAGE

TR48 CHASSIS and BODY

No production bodied vehicles allowed in this class.

TR49 HOSES

TR50 IDENTIFICATION MARKINGS

Unlimited Off-Road Racing will assign race numbers.

TR51 ADVERTISING on VEHICLES

TR52 RADIO EQUIPMENT

TR53 WORKMANSHIP

TR54 TRACKING DEVICE