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acceleration explained.


This was sent to me in a Email. Not sure how much of it is true? Thought some might find interesting.

* One Top Fuel dragster outfitted with a 500 cubic-inch replica Dodge (actually Keith Black, etc) Hemi engine makes more horsepower (8,000 HP) than the first 4 rows at NASCAR's Daytona 500.
* Under full throttle, a dragster engine will consume 11.2 gallons of nitro methane per second; a fully loaded Boeing 747 consumes jet fuel at the same rate but with 25% less energy being produced.
* A stock Dodge Hemi V8 engine cannot produce enough power to merely drive the dragster's supercharger.
* With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lockup at full throttle.
* At the stoichio metric 1.7:1 air/fuel mixture for nitro methane the flame front temperature measures 7050 degrees F.
* Nitro methane 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.
* Dual magnetos supply 44 amps to each spark plug. Which is typically the output of an electric arc welder in each cylinder.
* Spark plug electrodes are totally consumed during a pass. After 1/2 way thru the run, the engine is 'dieseling' from compression and the glow of the 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 the affected cylinders and then explodes with enough sufficient force to blow the cylinder heads off the block in pieces or split the block in half !!
* Dragsters reach over 300 MPH +... before you have completed reading this sentence.
* In order to exceed 300 MPH in 4.5 seconds, a dragster must accelerate an average of over 4 G's. In order to reach 200 MPH well before reaching half-track, at launch the acceleration approaches 8 G's.
* Top Fuel engines turn approximately 540 revolutions from light to light!
* Including the burnout, the engine must only survive 900 revolutions under load.
* The redline is actually quite high at 9500 RPM.
* THE BOTTOM LINE: Assuming all the equipment is paid for, the pit crew is working for free, & NOTHING BLOWS UP, each run will cost an estimated $1,000 per second.
0 to 100 MPH in .8 seconds (the first 60 feet of t he run)
0 to 200 MPH in 2.2 seconds (the first 350 feet of the run)
6 g-forces at the starting line (nothing accelerates faster on land)
6 negative g-forces upon deployment of twin 'chutes at 300 MPH
An NHRA Top Fuel Dragster accelerates quicker than any other land vehicle on earth . . quicker than a jet fighter plane . . . quicker than the space shuttle....or snapping your fingers !!
The current Top Fuel dragster elapsed time record is 4.420 seconds for the quarter-mile (2004, Doug Kalitta). The top speed record is 337.58 MPH as measured over the last 66' of the run (2005, Tony Schumacher).
Let's now put this all into perspective:
Imagine this...........You are driving a new $140,000 Lingenfelter twin-turbo powered Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged & ready to 'launch' down a quarter-mile s trip as you pass. You have the advantage of a flying start. You run the 'Vette hard, on up through the gears and blast across the starting line & pass the dragster at an honest 200 MPH.... The 'tree' goes green for both of you at that exact moment.
The dragster departs & starts after you. You keep your foot buried hard to the floor, and suddenly you hear an incredibly brutally screaming whine that seares and pummels your eardrums & within a mere 3 seconds the dragster effortlessly catches & passes you. He beats you to the finish line, a quarter-mile away from where you just passed him. Think about it - from a standing start, the dragster had spotted you 200 MPH.....and it not only caught, but nearly blasted you off the planet when he passed you within a mere 1320 foot long race !!!!
That, my acceleration.
Yes an asume display of power. A good friend of mine use to run TF and looking at the time slips was truly amazing. 60' time in less than 1 second. 0-100 mph in less than 1 second. 1/8 mile et was something like 3.6 seconds at 200 mph.
I remember many years ago when they did the impossible, broke the 6 second barrier.
Now they are something like 3.8 seconds.
I don't buy this.....

Top Fuel engines turn approximately 540 revolutions from light to light! Including the burnout, the engine must only survive 900 revolutions under load.

The motor and rear tires do not spin 1 to 1. You get tremendous tire spin during the burnout. ALSO with the centrifical clutch setup the clutch (thus motor) spins much more until full engagement at 3/4 track or so. Or else the tires would just go up in smoke at the hit of the throttle. So I think that 900 revolutions is BOGUS.
Not agreeing with the simple math.

If an engine is turning 9500 rpm...divide by 60 seconds you get 158.333 revs per second. Multiply that by 4.42 seconds you get 699.8 revs. Add another second for the burnout even though the burnouts is not done at full throttle...858 revs.

Or am I missing something??
And a car traveling at 200 mph will cover 1320 feet in 4.500005 seconds. Therefore a 4.42 sec. dragster will win by .08 seconds. That much works. However, I wonder about the 11.2 gal of fuel per second. 4.42 seconds * 11.2 gallons = 49.5 gallons. Do they carry that much fuel? What am I missing here?

No, that metric is completely false. At WOT, the pumps are capable of moving approximately 80 gallons per minute.

Fuel capacity varies a bit from car to car. Some of the more recent 'high-boy' cars coming out of Murf McKinney's shop have a bit more fuel capacity, but you can figure something in the range of 24-25 gallons of capacity.

Starting line g-forces are also exaggerated. Something back in the 4.7 - 4.8 range is realistic. With numbers in the -4 range when the chutes hit.
Reviving this thread a little because, I just attended my first NHRA event. All I can say is … Damm. I had know idea. TV doesn’t do them justice. I watch Jim Heads funny car blown up in front of us and still don’t know how he could be alive. Local strip will never be the same for me.
All I can say is … Damm. I had know idea.
Uh-oh, we've sacrificed another to the nitro gods. :)

It's pretty unusual to see him blow his stuff up, particularly in so spectacular a fashion. He runs very well on a much more conservative tune-up than some of the heavily-funded cars. I've always liked Jim and have known him since the days he was running Comp with his Afternoon Delight C/ED. Anyone remember that car, or did I just show my age again? Head's a personable fellow that has no problem speaking his opinion when he has safety concerns with NHRA. It's common to see a handful of racers doing the reciprocal ass-smooching with people like Tom Compton and Graham (a.k.a. Dim) Light, but you'll never find Jim Head involved. He tells it like it is, whether they want to hear it or not.
For those interested in Head's boomer at Topeka -


I made a couple of quick calls and talk around the pits had the cause down to a broken crank gear. Pretty amazing what can happen when valve timing goes awry, eh? :)
Here is the video pretty amazing he wasn't seriously hurt safety is job one.
Went to the drags last summer and there was a guy there running a Dodge slant-6 that made it to the finals up against all the other V-8's. I was sitting at the start lights and was amazed at how fast those guys dissappear down the track. That slant-6 sounded like a screaming sewing machine as opposed to the V-8 roaring thunder.

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