Top-Fuel Racing refers to a class of drag racing in
which the cars are run on 85% nitromethane and about 15% methanol also known
as racing alcohol, instead of gasoline. The nitromethane used to power the
engines of top fuel dragsters costs about $30 per gallon.
Top Fuel dragsters use between 10 and 12 gallons (38 to 45 L) of fuel
for a complete pass, including the burnout, backup to the starting line, and
quarter-mile run. The engine makes about 3.4 times as much power as a
similar displacement engine running gasoline.
The engines are purpose-designed V8 engines, whose
basic design is descended from the Chrysler Hemi engine. The engines can
typically produce at least 8,000 horsepower. The supercharger
alone requires 1500 horsepower to turn it to generate the great
intake manifold pressures for the engines. While going down the track the
engines run on the verge of hydraulic lock (that is, the air-fuel mixture is
compressed so much it is almost a liquid).
Two spark plugs per cylinder are
the rule, with some teams experimenting with three. The spark plug
electrodes are completely consumed during a run, but spark ignition is not
necessary after the first half of the pass, since the motor is dieseling
(igniting the air-fuel mixture without the help of a spark) because of the
compression and extremely hot exhaust valves. After each pass, the whole
engine is taken apart and gone through, and much of it is replaced. The
engine is therefore designed for quick and easy disassembly and reassembly.
On average, each run costs about $2,000 - $3,000.
Top fuel dragsters compete in a 1/4 mile (0.4 km) race and complete it in less
than 4.5 seconds at upwards of 330 mph (530 km/h). Top Fuel dragsters are the
fastest linear accelerating vehicles in the world. A Top Fuel dragster
accelerates from 0 to 100 mph (160 km/h) in less than 0.8 second, almost 11
times quicker than it takes a production Porsche 911 Turbo to reach the same
speed. They can exceed 280 mph (450 km/h) in just 660 feet (0.2 km).