So what is real acceleration??

IwantMKIII

WVU MAEngineering
Jun 12, 2007
2,477
0
0
Perkasie, PA
Thought this was very interesting...(PS i searched, nothing came up so this shouldn't be a repost but we all know how that goes)



DEFINITION OF ACCELERATION

One top fuel dragster 500 cubic inch Hemi engine makes more horsepower
than the first 5 rows of stock cars at the Daytona 500. (approx - 8000 hp)

Under full throttle, a dragster engine consumes 1-1/2 gallons of nitro
methane per second; a fully loaded 747 consumes jet fuel at the same
rate with 25% less energy being produced.

A Dodge Hemi V8 street engine cannot produce enough power to drive the
dragster's supercharger.

With 3,000 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 lock at full throttle.

At the stoichiometric (stoichiometry: methodology and technology by
which quantities of reactants and products in chemical reactions are
determined) 1.7:1 air/fuel mixture of nitro methane, the flame front
temperature measures 7,050 deg F. (approx - 14.7:1+ on a car)

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. This is essentially the
output of an arc welder in each cylinder.

Spark plug electrodes are totally consumed during a pass. After halfway,
the engine is dieseling from compression, plus the glow of exhaust
valves at 1,400 deg 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 sufficient force to blow
cylinder heads off the block in pieces or split the block in half.

In order to exceed 300 mph in 4.5 seconds, dragsters must accelerate an
average of over 4G's. In order to reach 200 mph (well before
half-track), the launch acceleration approaches 8G's.

Dragsters reach over 300 miles per hour before you have completed
reading this sentence.

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 9,500 rpm.

Assuming all the equipment is paid off, the crew worked for free, and
for once NOTHING BLOWS UP, each run costs an estimate $1,000.00 per
second. Most top fuel crews include 6 team members and a crew chief and
today
few of the top teams have anyone working for free. If you run 4 passes
to qualify and
4 passes on Sunday that is about $64k plus crew, driver and breakage and
there is plenty of that in Top fuel. No wonder they need Big sponsor bucks.

The current top fuel dragster elapsed time record is 4.441 seconds for
the quarter mile (10/05/03, Tony Schumacher). The top speed record is
333.00 mph (533 km/h) as measured over the last 66' of the run (09/28/03
Doug Kalitta).

You are driving the average $140,000 Lingenfelter "twin-turbo" powered
Corvette Z06. Over a mile up the road, a top fuel dragster is staged and
ready to launch down a quarter mile strip as you pass. You have the
advantage of a flying start. You run the Vette hard up through the
gears and blast across the starting line and pass the dragster at an
honest 200 mph. The "tree" goes green for both of you at that exact split
second
moment. The dragster launches and starts after you.

You keep your foot down hard, but you hear an incredibly brutal whine
that sears your eardrums and within 3 seconds, the dragster catches and
passes you. He beats you to the finish line, a quarter mile away from
where you just passed him by a significant margin. Think about it;
from a standing start, the
dragster had spotted you 200 mph and not only caught you, but nearly
blasted you off the road when he passed you all within a mere 1,320 foot
long race course.
 

trydrew

Suprafied
Nov 4, 2005
1,038
0
36
Earth
I've seen that before, but to be quite honest, I am amazed just the same everytime I read it...
 

Doward

Banned
Jan 11, 2006
4,245
0
36
Alachua, FL
Just to put that in perspective - the most powerful thing ever to be ridden by man is the Saturn V rocket.

The Apollo missions recorded an average of 4.5-4.6g's maximum on takeoff. IIRC, something like 6.8 G's was the highest re-entry force.
 

WhtMa71

D0 W3RK
Apr 24, 2007
1,813
0
36
Macon, GA
Anyone here ever been to a top fuel race? The noise those cars makes is just insane..Even shakes the ground. I saw a video somewhere of an injector from one of those running at full throttle..it was crazy.
 

Jayhall

WHIP THE PISS OUT OF THEM
May 7, 2005
1,167
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Surrey BC
i went dowm to Pacific Raceways and watched the top fuel cars for a day. Absolutly amazing. When i left, my shirt had unburnt fuel all over it, becasue i was sitting right behind the track. Those cars dont drive straight either
 

trydrew

Suprafied
Nov 4, 2005
1,038
0
36
Earth
RedEj8 said:
Anyone here ever been to a top fuel race? The noise those cars makes is just insane..Even shakes the ground. I saw a video somewhere of an injector from one of those running at full throttle..it was crazy.

I went to the NHRA nationals last year for a school trip. Didn't have to pay a thing, it was awesome. You're right, those things are so GD loud it's insane. It gives you an adrenaline rush just watching.

Oh and when you mentioned that video, a picture of a fire hose popped up in my head. :biglaugh:
 

Isphius

Supra-less :(
May 30, 2006
359
0
0
long branch
"A Dodge Hemi V8 street engine cannot produce enough power to drive the
dragster's supercharger."


I lol-ed at that, and also at the same time realized that that is one badass supercharger, or dodge just cant build motors. Or a combo of those. Ive also heard that in a single pass those motors suck in the entire volume of giants stadium in fresh air
 

Clueless

Banned
Feb 22, 2006
980
0
0
38
Columbus, Indiana
Isphius said:
"A Dodge Hemi V8 street engine cannot produce enough power to drive the
dragster's supercharger."


I lol-ed at that, and also at the same time realized that that is one badass supercharger, or dodge just cant build motors. Or a combo of those. Ive also heard that in a single pass those motors suck in the entire volume of giants stadium in fresh air

dude, that would be one bad-ass margarita blender! :naughty:
 

annoyingrob

Boosted member
Jul 5, 2006
2,304
0
0
Calgary, Alberta, Canada
IwantMKIII said:
If spark momentarily fails early in the run, unburned nitro builds up in
the affected cylinders and then explodes with sufficient force to blow
cylinder heads off the block in pieces or split the block in half.
This is because, what was said above, they run 1.7:1 A/F on nitromethane. They pump in JUST enough fuel into the cylinders, just before it hydro-locks. If there's just a little bit of residual fuel left, the motor will hydro-lock on the next rotation, and push itself apart.


Another interesting fact, they don't run a transmission. They simply slip the clutch to accelerate. If you've ever noticed the black cloud coming from behind the dragsters, that's the clutch dust coming off as the clutch consumes itself. I'm not certain, but I believe they're 8 or 12 plate clutches, and obviously need to be changed after every race.