Top Fuel Dragsters: Over 10,000 Horsepower Of Nitromethane Fury

Top Fuel drag racing and the dragsters that compete are really something else. I recently talked with my uncle who owns some jet skis who I discovered really likes watching NHRA drag racing. He told me a bunch of cool stuff about the racing and the cars they use. Here’s what we talked about…

Half of the drag runs that Top Fuel dragsters do by the end of the run they are only running on 7 or 6 cylinders because the engine basically destroys itself during the run; because of this, Top Fuel dragster engines are built so they can be rebuilt quickly and easily. No current chassis dyno is capable of handling the sheer power of the Top Fuel cars so the horsepower the cars make has to be estimated and right now, the nitromethane powered cars probably make around 10,000 horsepower or more.

Here we see a Top Fuel pit crew rebuilding an engine... for probably the 143rd time

Because Top Fuel dragsters have so much power, they have a graduated clutch pack that engages the engine in increments because if the dragster unleashed all it’s power right at the launch, it would just spin it’s tires. Even when the clutches fully engage when the car is traveling at 300 MPH, the tires still spin. At the end of the run, some of the clutches are welded together because of how hot the clutches get.

During the early days of top fuel drag racing, the clutches used were really tight and grabby and the cars would smoke the tires through the entire race. However, one day, a technician didn’t properly tighten down the clutch and the dragster actually went faster because of it. Since that point, top fuel dragsters have ditched tight clutches for loose ones.

This is what an old school top fuel dragster looks like

Nowadays so the drivers of the Top Fuel dragsters won’t get hurt during the intense accelerations and deccelerations they experience during a race, their head is strapped to the roll cage so it can’t snap back or forward.

Various Fun Facts

It takes 600 horsepower to turn the superchargers on Top Fuel dragsters
The superchargers are overdriven (they spin faster than the crankshaft of the engine) and can produce at least 50 pounds of boost.
The engines in Top Fuel dragsters are based off of the 426 Hemi V8 from the 1970’s
Top Fuel dragsters can travel from a stand still to 1,000 feet in as fast as 3.7 seconds at speeds of 335 MPH
Exhaust gases from the open headers at full throttle can force the car into the ground with as much as 1,100 pounds of force
A Top Fuel dragster uses up to 23 gallons of fuel in a single race
Nitromethane doesn’t need as much air as gasoline to combust; 14.7 to 1 air to fuel ratio for gasoline and 1.7 to 1 air to fuel ratio for nitromethane.

“Nitromethane also has a high latent heat of vaporization, meaning that it will absorb substantial engine heat as it vaporizes, providing an invaluable cooling mechanism. The laminar flame speed and combustion temperature are higher than gasoline at 0.5 m/s and 2400 °C respectively. Power output can be increased by using very rich air fuel mixtures. This is also something that helps prevent pre-ignition, something that is usually a problem when using nitromethane.”