| All About the HEMI
Introduction
Chrysler's Hemi is considerd by many to be the finest engine ever made. I have created this website to be a (hopefully) useful resource for those interested in the Hemi, and for those always looking to learn a bit more. Thanks, enjoy the website and please spread the word. | Top Fuel Dragster Trivia | One TF dragster's 500-inch Hemi makes more horsepower than the first 8 rows at the Daytona 500.
Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.
A stock hemi will not produce enough power to drive the dragster's supercharger.
With nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
Dual magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame front of nitromethane measures 7050 degrees F.
Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.
Spark plug electrodes are totally consumed during a pass. After ½ way, the engine is dieseling from compression - plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting the fuel flow.
If spark momentarily fails early in the run, unburned nitro builds up in those cylinders and then explodes with a force that can blow cylinder heads off or split the block in half.
To exceed 300 mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. But in reaching 200 mph well before 1/2 track, launch acceleration is closer to 8G's.
If all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs $1000.00 per second.
Dragsters reach over 300 miles per hour before you have completed reading this sentence.
Top Fuel Engines turn ONLY 540 revolutions from light to light!
The redline is actually quite high at 9500rpm
The current TF dragster elapsed time record is 4.477 seconds for the quarter mile (06/02/01 Kenny Bernstein)
Putting all of this in perspective:
You are driving an average Lingenfelter powered "twin-turbo" Corvette and a Top Fuel dragster is staged and ready to launch as you pass. You blast past at an honest 200 mph. At this moment, the dragster launches and starts after you. Within seconds the dragster passes. He beats you to the quarter mile finish. That, folks, is acceleration.
Think about it, from a standing start, this phenomenal machine has spotted you 200mph and not only caught, but nearly blasted you off the road when he passed you within a mere 1320 feet.
Now....., tell me about the time you spun the wheels and laid rubber on dry concrete.
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Scott Moseman (scottm@scotech.com)
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