[DeTomaso] NPC- Definition of acceleration

Mon Oct 12 17:04:47 EDT 2009

There must be some gross error in my calculation. I don't see how they 
can spend "22.75 gallons of fuel during warmup, burnout, staging, and 
the quarter-mile run." otherwise.

Thomas Tornblom skrev:
> Göran Malmberg skrev:
>> Problem arises if there is missfiering, the hydrolock is a result.
> 
> Is this really true btw?
> 
> I just did a quick calculation and I don't see how there could be hydro 
> lock, even if it doesn't ignite.
> 
> Assume a 500 cui engine, or 8 liter.
> Air mass is ~9500l/kg at atmospheric pressure.
> Density of nitro is 1.13 kg/l.
> Lambda 1 AFR for nitro is 1.7:1 (by weight)
> Assume 3 bar boost
> 
> So each cylinder gets 1 liter of air at 3 bar boost per cycle, or 3/9500kg.
> 
> The amount of fuel (by weight) is 1/1.7 of the amount of air, 3/(9500x1.7).
> 
> The amount of fuel by volume is 1.13 x the amount by weight.
> 
> So the volume of fuel per cycle is:
> 
> 3/(9500x1.7x1.13), which if I have calculated everything correctly 
> amounts to 0.16cc.
> 
> I don't see how this would result in a hydro lock, unless the combustion 
> chambers would have zero size.
> 
> It appears that many of the items on this list are myths.
> 
> Another list can be found here:
> http://www.motortrend.com/features/112_0502_top_fuel_numbers/index.html
> 
> What I find interesting is that the crank only turns 569 turns over the 
> quarter mile, and the intake valves open just 284 times :-)
> 
> Thomas
> 
> 
>> Dual sparkpluggs is a good idea then.
>> Goran
>>
>> -----Ursprungligt meddelande-----
>> Från: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
>> För Sean Korb
>> Skickat: den 12 oktober 2009 20:57
>> Till: List Pantera
>> Ämne: Re: [DeTomaso] NPC- Definition of acceleration
>>
>> 58-65 degrees spark advance.  By the time the piston is at TDC, much
>> of the charge has already burned.
>>
>> sean
>>
>> On Mon, Oct 12, 2009 at 2:28 PM,  <adin at frontier.net> wrote:
>>> An old, old email.
>>>
>>> But, if one thinks a moment . . . .(whew) running a 1.7 to 1 fuel mix
>>> means that over 1/3 of the charge is "liquid" ??????  At that
>>> compresion ratio, isn't that true hydro-lock????
>>>
>>> How does that work?
>>>
>>>
>>>
>>>
>>> Quoting "michael at michaelshortt.com" <michaelsavga at gmail.com>:
>>>
>>>> A friend sent this to me, fun read.
>>>>
>>>>
>>>>
>>>> For all of you old drag racers
>>>>
>>>>
>>>>
>>>> THE DEFINITION OF ACCELERATION!!
>>>>
>>>>  One top fuel dragster 500 cubic inch Hemi engine makes more
>> horsepower
>>>> than the first 4 rows of stock cars at the Daytona 500.
>>>>
>>>>  It takes just 15/100ths of a second for all 6,000+ horsepower of an
>> NHRA
>>>> Top Fuel dragster engine to reach the rear wheels.
>>>>
>>>>  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
>>>> but with 25% less energy being produced.
>>>>
>>>>  A stock Dodge Hemi V8 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.
>>>>
>>>>  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 heat of the exhaust gases.
>>>>
>>>>  Dual magnetos supply 44 amps to each spark plug. This is 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
>> immediately
>>>> builds up in
>>>> the affected cylinder 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 one 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 red line 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.
>>>>  The current top fuel dragster elapsed time record is 4.428 seconds
>> for
>>>> the quarter mile (11/12/06, Tony Schumacher, at Pomona , CA ). The
>> top speed
>>>> record is 336.15 mph as measured over the last 66' of the run
>> (05/25/05 Tony
>>>> Schumacher, at Hebron , OH ).
>>>>
>>>>  Putting all of this into perspective:
>>>>
>>>>  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 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.
>>>>
>>>>  Think about it, from a standing start, the dragster had spotted you
>> 200
>>>> mph and not only caught, but nearly blasted you off the road when he
>> passed
>>>> you within a mere 1,320 foot long race course.
>>>>
>>>>  ... and that my friend, is ACCELERATION!
>>>>
>>>> --
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Michael L. Shortt
>>>> Savannah, Georgia
>>>> www.michaelshortt.com
>>>> michael at michaelshortt.com
>>>> 912-232-9390
>>>>
>>>>
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> 
> 

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