Funny Car
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Funny Car is an NHRA drag racing car class. Other common classes include top fuel dragsters and pro stock. Funny cars are dragsters with a massive front-mounted engine. The cars are rear-wheel driven with huge distinctive rear wheels. The cars also differ from top fuel in that funny cars have some sort of an automotive body over the chassis, making them look like stock cars tilted forward on huge wheels.
The NHRA has strict guidelines for funny cars. Most of the rules relate to the engine. In short, the engines can only be V-8's at 90 degrees. (The most popular design has been based on the 426 Chrysler Hemi.) There can only be two valves per cylinder and superchargers are restricted to a basic Roots type—19 inch (483 mm) rotor case length with a width of 11.25 inches (286 mm). The engine displacement can only be from 490 to 500 in³ (8.0 to 8.2 L). Only single camshafts are allowed. There are two common bore-stroke combinations: 4.1875 × 4.50 inches (106.4 × 114.3 mm) (called a 3/4 stroker) and 4.25 × 4.375 in (108.0 × 111.1 mm) (called a 5/8 stroker). The 3/4 stroker is the most common combination used today and equals 496 in³ (8.1 L).
Engine blocks are usually made out of forged aluminum. Crankshafts are made from billet chrome-vanadium steel. Intake valves are titanium and of 2.40 inch (61 mm) diameter, while exhaust valves are 1.90 inch (48 mm) diameter made out of Inconel. Every funny car has ballistic blankets covering specific parts of the engine prone to explosion.
Funny car fuel systems are key to their immense power. Most systems will deliver from 500 to 600 pounds of fuel pressure at as much as 75 US gallons per minute (5 L/s). During a single run (Starting, burnout, backing up, staging, 1/4 mile) cars can burn as much as 15 US gallons (57 L) of fuel. The fuel mixture is usually 98-99% nitromethane with 1-2% alcohol. The ratio of fuel to air can be as high as 1:1. Compression ratios vary from 6:1 to 7:1. The engines in Funny cars commonly exhibit varying piston heights and ratios that are determined by the piston's proximity to the air intake. Funny cars have a fixed gear ratio of 3.20:1 and have a reverser. Wheelbase is between 100 and 125 inches (2.54 and 3.18 m). The car must maintain a 3 in (76 mm) ground clearance.
Various safety rules are also in place to protect the driver, spectators, and others. The most obvious requirement is a parachute to help slow the car down once it crosses the finish line.
As can be seen from the above, other than the engine placement and the body, Funny Cars are mechanically very similar to Top Fuel dragsters. Their quarter mile elapsed times are somewhat slower, due to the extra weight, but their top speeds can be faster, due to the aerodynamic advantages of having the tires enclosed from the air.
A well-known driver in Funny Car racing is John Force.