2019 IHRA Rulebook

IHRA 21 All harness sections must be mounted to the frame cross member, or reinforced mounting, and installed to limit driver’s body travel both upward and forward. Wrapping of belts around frame rail prohibited. Under no circumstances are bolts to be inserted through belt webbing for mounting. DRIVETRAIN CHAIN/BELT GUARD: All cars must be equipped with a guard to cover the width and at least the top run to the center line of the sprocket of any chains or belts. Guards must be minimum .060” steel, or .125” aluminum, and must be securely mounted; no tie wraps. Moving engine/drivetrain parts must be protected by frame rails or steel or aluminum guards to avoid unintentional contact. CLUTCH: All cars must be equipped with a dry centrifugal-type engine clutch. Chain or belt drive only. Axle clutches prohibited. FLYWHEEL: Aftermarket billet flywheel mandatory unless OEM type carburetor is used. Cast aluminium flywheel prohibited. Modification to stock units other than keyway modifications is prohibited. TRANSMISSION: Gear-type prohibited. Torque converter belt assembly units allowed. BRAKES & SUSPENSION: Two rear-wheel hydraulic drum or disc brakes, or IHRA accepted mechanical brakes mandatory. Hydraulic brake lines must be steel or steel braided. High pressure brake hose must be used with steel line for vibration connections. Front brakes permitted, but only in conjunction with rear brakes. Vehicle may have brakes on one wheel only if 7 inch minimum go kart puck type disc brake is used. Use of drive sprocket as a brake rotor prohibited. Drilling of brake components prohibited. Steel disc brake rotors are required and must be a minimum of 7-inch diameter with a .228-inch minimum thickness, dual steel brake rotors, 6-inch diameter with a 3/16 inch minimum thickness; or aluminum brake rotor, 11-inch diameter with a .228-inch minimum thickness. Line-loc prohibited. Hand brake permitted, but must be directly coupled to foot brake; hand brake cannot be independent of, or in lieu of, foot brake. Application and release of brakes must be a direct function of the driver; electronics, pneumatics, or any other device may in no way affect or assist brake operation. ELECTRICAL IGNITION SHUTOFF: A positive ignition shutoff switch, within easy reach of the driver, mandatory. A second shutoff switch on the center top portion of the deflector plate within easy reach of the crew or race official mandatory. All entries must have a mechanical shutoff switch to ground the spark plug located within easy reach of the driver. FC additional switch must be on the upper rear drivers side of the vehicle labeled as to function. TAIL LIGHT: Functional tail light mandatory. It must be visible from the rear of the car. ENGINE ENGINE: All vehicles restricted to a maximum of one, rear-mounted, five horsepower based, four-cycle engine. Porting, polishing and relieving of block is permitted. Welding to intake port is permitted. Machining of deck surface permitted. Adding material to deck surface in any matter will be prohibited. All components must be completely isolated from the drivers compartment. This includes fuel system. Accepted aftermarket engines: Metro Racing flathead, McGee Racing flathead, Tecumseh flathead, Pure Power Racing flathead, LPW Racing Products, JR Race Car flathead, Huddleston Performance flathead and R&S Machine flathead Monster Racing, SR 71 Racing, Soltz Racing M-1 machine block, TRS Race Engine, Briggs and Stratton 206 factory sealed crate engine, JR Race Cars Thumper JD2 and Punisher JD3 sealed crate engine. The crate engine must maintain un-tampered hologram seal installed at the factory. No alterations or modifications to Briggs and Stratton 206 crate engine permitted except for installation of exhaust header and air filter. CAMSHAFT: Any camshaft permitted. Any valve spring permitted. No overhead cams permitted. Any size valves permitted. CARBURETOR: Any means to pass fuel or air to the engine other than normally aspirated carburetor is prohibited. Auxiliary vacuum fuel pump allowed. Pressurized and/or fuel injection systems prohibited. Electric fuel pumps prohibited. CYLINDER HEAD: Aftermarket units permitted. FUEL: Gasoline or alcohol only. Nitrous oxide and/or nitromethane and/or propylene oxide prohibited in all classes. Fuel tank must be behind driver’s compartment, below the shoulder hoop of roll cage and securely mounted within frame rails. Maximum capacity of one gallon, must have screw-on or positive locking cap. All vents must be routed downward, away from driver and extend beyond the bottom of the fuel cell. No vented fuel caps permitted, except on Briggs & Stratton or Tecumseh stock tanks. IGNITION SYSTEM: Magneto or battery ignition systems permitted. Maximum one