Rolling Chasis
A Funny Car chassis -- which has a wheelbase of between 100 and 125 inches -- is fabricated from 179 3/4 feet (18 pieces) of 4130 chromoly tubing and costs approximately $20,000. For that price, the customer also receives front spindles, a steering box, seat, floor pan, motor plates, rear-end plates, fuel tank, all handles, clutch pedal, fuel-shutoff and parachute-release levers, control cables, oil-overflow tank, rollbar pads, and a finished body. The chassis alone weighs approximately 125 pounds.
Body
The carbon-fiber (graphite) body, formed of a special four-element graphite weave, must be a 1991 or later model two-door coupe or two-door sedan of a type originally mass-produced by an automobile manufacturer. A standard body is stretched and lengthened to the desired specifications and weighs between 87 and 89 pounds, depending on the roof area. The body alone costs more than $6,000. At the chassis shop, a pressure-relief panel, escape hatch, Lexan windows, rear spoiler, parachute-release assembly, and parachute mounting are installed. Openings for the headers also are cut, and all tinwork and supporting structure that holds the body to the chassis is completed. Finishing costs are between $8,000 and $11,000.
Engine
The engine of choice for the majority of teams is an aluminum replica of the famed 426 Chrysler Hemi. At least four manufacturers sell the engine blocks, which fetch $4,500 and will displace a maximum of 500 cubic inches once the crankshaft and rotating piston assemblies are in place. When equipped with cylinder heads and connecting rods carved from chunks of aluminum and when the intake manifold, supercharger, and fuel pumps are bolted in place, a nitro engine costs approximately $50,000.
Drivetrain
To prevent a loss of traction, power is transferred from the engine to the rear tires via a complex timer-controlled clutch system. The centrifugal pressure that squeezes the four discs and three steel floater plates together is applied gradually in a series of infinitesimal stages controlled by a hydraulic-fluid-powered throw-out bearing and ram until complete one-to-one lockup with the engine and drivetrain is achieved, approximately three seconds into the run. Clutch temperatures can soar to more than 1,000 degrees F. All Funny Cars run a standard rear-gear ratio of 3.20-1.
Supercharger
Mounted atop the engine's intake manifold, this belt-driven mechanical device rams air into the engine at a staggering rate. A nitro supercharger, spinning at 10,000 rpm (based on the typical rate of 30 percent more than the engine speed of approximately 8,000 rpm), will displace 100,000 cubic inches of air per minute.
Specifications
Funny Cars must weigh a minimum of 2,300 pounds and may not have a wheelbase that measures more than 125 inches or fewer than 100 inches. From the front of the car to a point 12 inches behind the centerline of the front axle, the cars must maintain a minimum ground clearance of three inches. The remainder of the car must have a two-inch clearance with the exception of the oil pan and exhaust headers. The front overhang may not exceed 40 inches, measured from the centerline of the front spindle. The underside of the body, including roof area, must be covered with a flame-retardant covering or coating.
Driver Safety Equipment
A complete fire-resistant driving suit, gloves, helmet, head sock, and 360-degree neck collar must be worn. Drivers must be secured in the cockpit with a five-point restraint system utilizing belts that are a minimum of three inches wide and covered with fire-resistant material and arm restraints. A fire-extinguishing system is mandatory. It must be a minimum of 20 pounds; 15 pounds must be directed to the engine compartment and five pounds or more dispersed in the driver compartment by means of an atomizing nozzle placed at the driver's feet. A working escape hatch must be installed in the roof to permit easy driver exit, and side windows must have a minimum six-inch-diameter opening adjacent to the driver to accommodate a fire hose.
Tires
The fat Goodyear slicks on back are 18 inches wide and nearly 10 feet in circumference (118 inches). Air pressure is a low four pounds. Most Funny Cars use a 23x5x15-inch front tire.
Fuel
The powerful elixir that helps coax more than 10 horsepower from every one of the engine's 500 cubic inches is the fuel, nitromethane. Nitromethane is produced by the nitration of propane; the end result is CH3NO2. It originally was produced in the 1800s and has been used widely as an organic solvent in the chemical industry during the last 50 years. Fed by a fuel pump that delivers 50 gallons per minute -- the equivalent of eight showerheads -- a typical Funny Car will gulp 15 gallons of nitro, at $18 per gallon, usually cut with a small percentage (2 percent to 5 percent) of methanol, during the burnout procedure and quarter-mile.
Brakes
The rear-brake rotors measure 10 3/4 or 11 1/2 inches in diameter and are made from either steel or carbon fiber; the front brakes have a rotor size of either 10 or 10 1/2 inches and are made from carbon or aluminum. The brakes, activated via a hand lever in the cockpit, are utilized on all four tires, but the car's primary braking system is a pair of parachutes that can produce up to five negative G forces of stopping power, enough to throw even a well-belted driver forward a few inches.
Rear Spoiler
Per NHRA guidelines, the rear spoiler must be mounted on, not built in, to the body. Made of aluminum and magnesium and capable of producing 5,000 pounds of downforce on the rear tires, it cannot measure more than 54 inches wide and more than five inches above the roof line. Unlike the rear wing on a Top Fueler, the spoiler is not easily adjusted. By moving an adjustable piece up or down, or by adjusting the gurney flap, a 10-percent variance in height can be achieved.
