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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 US$30 per U.S. gallon (US$8/L). Top Fuel dragsters use between 10 and 12
U.S. 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. |
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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 (6000 kW). The
supercharger alone requires 1500 horsepower (1100 kW) 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. |