Sunday, December 28, 2014

Lee Beard on top fuel engines and dragsters

in 1991 he was interviewed by John Phillips of Car and Driver, and this info was just in the Jan 2015 issue of Car and Driver, "Upfront" the Columnists


When asked to approximate how much power a Top Fuel engine might make (again, 1991 interview): he displayed a computer simulation that gave the numbers: 4221 pound-feet of torque and 5465 horsepower.

"Building an engine like that," Beard added, "it's like plunging your toilet with a Claymore mine. It will probably work, but it's hard on the toilet."

A Top Fuel engine, in a 3.77 second pass, consumes 5.2 gallons of fuel with a fuel line whose internal diameter is 3.0 inches, delivering Beijing-sourced nitromethane at 83-87 gallons per minutes at 600 psi.


RacePak data from Torrence's 2013 dragster was computed to ascertain that when Torrence hit the throttle, the engine revved to 8700 rpm in half a second, and the rear tires began serving up 4.0 g's of acceleration.

 At 2.5 seconds into the run, revs fell to 7075 rpm but g's climbed to 4.8.

At 300 mph Torrence's dragster faces 2880 pounds of drag - 560 pounds more than the car, with driver, weighs - meaning that the engine has to produce 2304 horsepower just to shove the air out of the way.

Then there's downforce from the wings - 5661 pounds' worth at 300 mph - meaning that the tires are supporting 7981 total pounds, although that figure climbs to 9885 pounds during a 329-mph pass.

With so much downforce, 387 horses are required just to keep the dragster rolling forward. Frictional losses in the final drive's ring-and-pinion, along with rotational losses from engine parts and axles and such, well, that requires another 577 horsepower.

In easy to remember numbers, in 1991 a top fueler made about 6000 horsepower, and now, they can make about 11,000 horsepower

http://www.freerepublic.com/focus/chat/3235947/posts?page=10


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