[DeTomaso] NPC- Definition of acceleration

Tue Oct 13 19:31:49 EDT 2009

I just put that up for fun, y'all take things way too seriusly, but here's
some more nitro for the fire....as it were.

Michael

Before their run, racers often perform a
*burnout<http://en.wikipedia.org/wiki/Burnout_(vehicle)>
*. This is done for three reasons (water is applied to initially break
traction, allowing the tires to spin up). First, it heats the tires up,
creating a sticky superficial layer of rubber on the tires. Secondly, it
removes debris from the tires. Thirdly, and most importantly, it coats the
track surface with rubber which greatly improves traction during the
subsequent launch. A Top Fueller's burnout alone can travel one quarter of
the way down the track.

At top engine speed, the exhaust gases escaping from the open headers
produce about 800-1000
pounds-force<http://en.wikipedia.org/wiki/Pound-force>(3.6
kilonewtons <http://en.wikipedia.org/wiki/Newton_(units)>) of
downforce<http://en.wikipedia.org/wiki/Downforce>.
The massive foil over and behind the rear wheels produces much more
downforce, peaking at around 12,000 lbf (53
kN<http://en.wikipedia.org/wiki/Kilonewton>)
when the car reaches a speed of about 325 mph (523 km/h).

Top Fuel dragsters are notorious for the deafening amount of noise their
engines create at full throttle (full noise). They generate 120 dB of noise,
[1] <http://en.wikipedia.org/wiki/Top_Fuel#cite_note-0> enough to cause some
peoples' eardrums physical pain. This is louder than a Boeing 747 jet
airliner at take-off power. The intense levels of sound are not only heard,
but also felt as pounding vibrations all over one's body, leading many to
compare the experience of watching a Top Fuel dragster make a pass to
'feeling as though the entire drag strip is being bombed'. Prior to the
dragsters going down the strip, race announcers usually advise spectators to
cover or plug their ears—indeed, ear plugs and even earmuffs are often
handed out to fans at the entrance to a Top Fuel event.
[edit<http://en.wikipedia.org/w/index.php?title=Top_Fuel&action=edit&section=2>
] The fuel

NHRA <http://en.wikipedia.org/wiki/NHRA> regulations limit the composition
of the fuel to a maximum of 90%
nitromethane<http://en.wikipedia.org/wiki/Nitromethane>(as of 2008);
the remainder is largely
methanol <http://en.wikipedia.org/wiki/Methanol>. However, this mixture is
not mandatory, and less nitromethane can be used if desired.

Kenny Bernstein <http://en.wikipedia.org/wiki/Kenny_Bernstein> was the first
drag racer in NHRA history to break 300 mph (480 km/h) in such a class of
car on the 1/4 mile in March, 1992. Bernstein took his dragster over 300 mph
(480 km/h) using a mixture of 90-to-100% nitromethane at the time. Despite
nitromethane having a much lower energy density (11.2 MJ/kg) than either
gasoline (44 MJ/kg) or methanol (22.7 MJ/kg), its addition to the fuel
mixture has the net effect of increasing engine output by around 2.3 times
compared to gasoline for the same mass of air -- 14.6 kg of air is required
to burn one kilogram of gasoline, but only 1.7 kg of air for one kilogram of
nitromethane. Since an engine’s cylinder can only contain a limited amount
of air on each stroke, 8.7 times more nitromethane than gasoline can be
burned in one stroke.

The high temperature of vaporization of nitromethane also means that it will
absorb substantial engine heat as it vaporizes, providing an invaluable
cooling mechanism. The laminar flame
speed<http://en.wikipedia.org/wiki/Flame_speed>and combustion
temperature are higher than gasoline at 0.5 m/s and 2400 °C
respectively. Power output can be increased by using very rich air fuel
mixtures. This is also something that helps prevent pre-ignition, something
that is usually a problem when using nitromethane.

Due to the relatively slow burn rate of nitromethane, very rich fuel
mixtures are often not fully ignited and some remaining nitromethane can
escape from the exhaust pipe and ignite on contact with atmospheric oxygen,
burning with a characteristic yellow flame<http://en.wikipedia.org/wiki/Flame>.
Additionally, after sufficient fuel has been combusted to consume all
available oxygen, nitromethane can combust in the absence of atmospheric
oxygen, producing hydrogen <http://en.wikipedia.org/wiki/Hydrogen>, which
can often be seen burning from the exhaust pipes at night as a bright white
flame. In a typical run the engine can consume as much as 103 litres (22.75
gallons) of fuel during warmup, burnout, staging, and the quarter-mile run.
[edit<http://en.wikipedia.org/w/index.php?title=Top_Fuel&action=edit&section=3>
] Top fuel engines
<http://en.wikipedia.org/wiki/File:Top_Fuel_engine.jpg>
<http://en.wikipedia.org/wiki/File:Top_Fuel_engine.jpg>
Engine of a top fuel car

Like many other motor sport formulas originating in the United States, the
NHRA <http://en.wikipedia.org/wiki/NHRA> favors heavy restrictions on engine
configuration, rather than technological development. This restricts the
teams to using many decades old technologies* This only relates to basic
engine configuration; most other areas are under continuous development e.g.
fuel injection,clutch operation,ignition and aero parts.

The engine used to power a Top Fuel drag racing car has its roots in the
second generation Chrysler Hemi <http://en.wikipedia.org/wiki/Hemi> 426
"Elephant Engine" made 1964-71. Although the Top Fuel engine is built
exclusively of specialist parts, it retains the basic configuration with two
valves per cylinder activated by pushrods from a centrally-placed camshaft.
The engine has hemispherical combustion chambers, a 90 degree V angle; 4.8"
bore pitch and a .54" cam lift. The configuration is identical to the
overhead valve, single camshaft-in-block "Hemi" V-8 engine which became
available for sale to the public in selected Chrysler Corporation (Dodge,
DeSoto, and Chrysler) automotive products in 1952.

The NHRA competition rules limit the displacement to 500 cubic inch (8194
cc). A 4.1875" (106.4 mm) bore with a 4.5" (114.3 mm) stroke are customary
dimensions. Larger bores have been shown to weaken the cylinder block.
Compression ratio is about 6.5:1, as is common on engines with overdriven
(the supercharger is driven faster than the crankshaft speed) superchargers.

The block <http://en.wikipedia.org/wiki/Cylinder_block> is CNC
machined<http://en.wikipedia.org/wiki/CNC_machine>from a piece of
forged <http://en.wikipedia.org/wiki/Forge> aluminium. It has press-fitted
ductile iron liners. There are no water passages in the block which adds
considerable strength and stiffness. Like the original Hemi, the racing
cylinder block has a long skirt (to reduce piston "rocking" at the lower
limit of piston travel); there are five main bearing caps which are fastened
with aircraft-standard-rated steel studs; with additional reinforcing main
studs and side bolts. There are three approved suppliers of these
custom-made after-market blocks, from which the teams may choose.

The cylinder heads <http://en.wikipedia.org/wiki/Cylinder_head> are
CNC-machined from aluminum
billets<http://en.wikipedia.org/wiki/Billet_(manufacturing)>.
As such, they have no water jackets and rely entirely on the incoming
air/fuel mixture for their cooling. The original Chrysler design of two
large valves per cylinder is used. The intake valve is made from solid
titanium <http://en.wikipedia.org/wiki/Titanium> and the exhaust from
solid Nimonic
80A<http://en.wikipedia.org/w/index.php?title=Nimonic_steel&action=edit&redlink=1>or
similar. Seats are of ductile
iron <http://en.wikipedia.org/wiki/Ductile_iron>.
Beryllium-copper<http://en.wikipedia.org/wiki/Beryllium_copper>has
been tried but its use is limited due to cost. Valve sizes are around
2.45" (62.2 mm) for the intake and 1.925" (48.9 mm) for the exhaust. In the
ports there are integral tubes for the push rods. The heads are sealed to
the block by copper gaskets and stainless
steel<http://en.wikipedia.org/wiki/Stainless_steel>
o-rings <http://en.wikipedia.org/wiki/O-ring>. Securing the heads to the
block is done with aircraft-rated steel studs.

The camshaft is billet steel, made from 8620 carbon steel or similar. It
runs in five oil pressure lubricated bearing shells and is driven by gears
in the front of the engine. Mechanical roller lifters ride atop the cam
lobes and drive the steel push rods up into the steel rockers that actuate
the valves. The rockers are of roller type on the intake side, high
pressures on the exhaust limits its use to the intake side only. The steel
roller rotates on a steel roller bearing and the steel rocker arms rotate on
a titanium shaft within bronze bushings. Intake rockers are billet while the
exhausts are investment cast. The dual valve
springs<http://en.wikipedia.org/w/index.php?title=Valve_spring&action=edit&redlink=1>are
of coaxial type and made out of titanium. Valve retainers are also
made
of titanium, as are the rocker covers.

Billet steel crankshafts <http://en.wikipedia.org/wiki/Crankshaft> are used;
they all have a cross plane a.k.a. 90 degree configuration and run in five
conventional bearing shells. 180 degree
crankshafts<http://en.wikipedia.org/w/index.php?title=180_degree_crankshaft&action=edit&redlink=1>have
been tried and they can offer increased power, even though the exhaust
is of open type. A 180 degree crankshaft is also about 10 kg lighter than 90
degree crankshaft, but they create a lot of vibration. Such is the strength
of a top fuel crankshaft that in one incident, the entire engine block was
split open and blown off the car during an engine failure, and the crank,
with all eight connecting rods and pistons, was left still bolted to the
clutch.

Pistons <http://en.wikipedia.org/wiki/Piston> are of forged aluminium, 2618
alloy. They have three rings <http://en.wikipedia.org/wiki/Piston_ring> and
aluminium buttons retain the 1.156" x 3.300" steel pin. The piston is
anodized <http://en.wikipedia.org/wiki/Anodize> and
Teflon<http://en.wikipedia.org/wiki/Polytetrafluoroethylene>coated to
prevent galling during high temperature operation. The top ring is
an L-shaped Dykes ring that provides a good seal during combustion but a
second ring must be used to prevent oil from entering the combustion chamber
during intake strokes as the Dykes-style ring offers less than optimal
combustion gas sealing. The third ring is an oil scraper ring whose function
is helped by the second ring. The connecting
rods<http://en.wikipedia.org/wiki/Connecting_rod>are of forged
aluminium and do provide some shock damping, which is why
aluminum is used in place of titanium, because titanium connecting rods
transmit too much of the combustion impulse to the big-end rod bearings,
endangering the bearings and thus the crankshaft and block. Each con rod has
two bolts, shell bearings for the big end while the pin runs directly in the
rod.

The supercharger <http://en.wikipedia.org/wiki/Supercharger> is a 14-71 type
Roots blower <http://en.wikipedia.org/wiki/Roots_blower>. It has twisted
lobes and is driven by a toothed
belt<http://en.wikipedia.org/wiki/Toothed_belt>.
The supercharger is slightly offset to the rear to provide an even
distribution of air. Absolute manifold
pressure<http://en.wikipedia.org/wiki/Manifold_pressure>is usually
3.8-4.5 bar (56-66 PSI), but up to 5.0 bar (74 PSI) is possible.
The manifold is fitted with a 200 psi burst plate. Air is fed to the
compressor from throttle <http://en.wikipedia.org/wiki/Throttle> butterflies
with a maximum area of 65 sq. in. At maximum pressure, it takes
approximately 400 horsepower (300 kW) to drive the supercharger.

These superchargers are in fact derivatives of General
Motors<http://en.wikipedia.org/wiki/General_Motors>scavenging-air
blowers for their two-cycle diesel
engines <http://en.wikipedia.org/wiki/Diesel_engine>, which were adapted for
automotive use in the early days of the sport. The model name of these
superchargers delineates their size; *i.e.* the once commonly used 6-71 and
4-71 blowers were designed for General Motors diesels having six cylinders
of 71 cubic inches each, and four cylinders of 71 cubic inches each,
respectively. Thus, the currently used 14-71 design can be seen to be a huge
increase in power delivery over the early designs.

Mandatory safety rules require a secured Kevlar-style blanket over the
supercharger assembly as "blower explosions" are not uncommon. The absence
of a protective blanket exposes the driver, team and spectators to shrapnel
in the event that nearly any irregularity in the induction of the air/fuel
mixture, the conversion of combustion into rotating crankshaft movements, or
in the exhausting of spent gasses is encountered.

The oil system<http://en.wikipedia.org/w/index.php?title=Oil_system&action=edit&redlink=1>has
a wet sump which contains 16 quarts of SAE 70 mineral or synthetic
racing oil. The pan is made of titanium or aluminium. Titanium can be used
to prevent oil spills in the event of a blown rod. Oil pressure is somewhere
around 160–170 lbf/in² <http://en.wikipedia.org/wiki/Lbf/in%C2%B2> during
the run, 200 lbf/in² at start up, but actual figures differ between teams.

Fuel is injected by a constant flow
injection<http://en.wikipedia.org/w/index.php?title=Constant_flow_injection&action=edit&redlink=1>system.
There is an engine driven mechanical fuel pump and about 42 fuel
nozzles. The pump can flow 100 gallons per minute at 8000 rpm and 500 PSI
fuel pressure. In general 10 injectors are placed in the injector hat above
the supercharger, 16 in the intake manifold and two per cylinder in the
cylinder head. Usually a race is started with a leaner mixture, then as the
clutch begins to tighten as the engine speed builds, the air/fuel mixture is
enriched. As engine speed builds pump pressure the mixture is made leaner to
maintain a predetermined ratio that is based on many factors, one of which
is primary one of race track surface friction. The
stoichiometry<http://en.wikipedia.org/wiki/Stoichiometry>of both
methanol and nitromethane is considerably greater than that of
racing gasoline, as they have oxygen atoms attached to their carbon chains
and gasoline does not. This means that a "fueler" engine will provide power
over a very broad range from very lean to very rich mixtures. Thus, to
attain maximum performance, before each race, by varying the level of fuel
supplied to the engine, the mechanical crew may select power outputs barely
below the limits of tire traction. Power outputs which create tire slippage
will "smoke the tires" and the race is often lost.

The air/fuel mixture is ignited by two 14 mm spark
plugs<http://en.wikipedia.org/wiki/Spark_plug>per cylinder. These
plugs are fired by two 44-
ampere <http://en.wikipedia.org/wiki/Ampere>
magnetos<http://en.wikipedia.org/wiki/Magneto_(electrical)>.
Normal ignition timing <http://en.wikipedia.org/wiki/Ignition_timing> is
58-65 degrees BTDC <http://en.wikipedia.org/wiki/BTDC>. (This is
dramatically greater spark
advance<http://en.wikipedia.org/w/index.php?title=Spark_advance&action=edit&redlink=1>than
in a gasoline engine as "nitro" and alcohol burn far slower.) Directly
after launch the timing is typically decreased by about 25 degrees for a
short time as this gives the tires time to reach their correct shape. The
ignition system limits the engine speed to 8400 rpm. The ignition system
provides initial 50,000 volts and 1.2 amperes. The long duration spark (up
to 26 degrees) provides energy of 950
millijoules<http://en.wikipedia.org/wiki/Millijoule>.
The plugs are placed in such a way that they are cooled by the incoming
charge. The ignition system is not allowed to respond to real time
information (no computer-based spark lead adjustments), so instead a
timer-based retard system is used.

The engine is fitted with open exhaust pipes, 2.75" in diameter and 18"
long. These are made of steel <http://en.wikipedia.org/wiki/Steel> and
fitted with thermocouples <http://en.wikipedia.org/wiki/Thermocouple> for
measuring of the exhaust
temperature<http://en.wikipedia.org/w/index.php?title=Exhaust_temperature&action=edit&redlink=1>.
They are called "zoomies" and exhaust gases are directed upward and
backwards. Exhaust temperature is about 500 °F (260 °C) at idle and 1796 °F
(980 °C) by the end of a run. A night run provides visual excitement with
slow-burning nitromethane flames many feet above this screaming spectacle of
acceleration. A "good run" is over in just 4.5 seconds, the noise ends, and
braking parachutes are seen in the distance, after a speed of over 325 miles
per hour (523 km/h) has been reached.

The engine is warmed up for about 80 seconds. After the warm up the valve
covers <http://en.wikipedia.org/wiki/Valve_cover> are taken off, oil is
changed and the car is refueled. The run including tire warming is about 100
seconds which results in a "lap" of about three minutes. After each lap, the
entire engine is disassembled and examined, and worn or damaged components
are replaced.
[edit<http://en.wikipedia.org/w/index.php?title=Top_Fuel&action=edit&section=4>
] Performance

Measuring the power output of a top fuel engine directly is not feasible.
(Actually this is done on those cars that have a Torque sensor incorporated
as part the RacePak data system[Hp=Torque x Rpm]). This is not, as is
sometimes stated, because no
dynamometer<http://en.wikipedia.org/wiki/Dynamometer>exists that can
measure the output of a Top Fuel engine; in reality,
dynamometers capable of measuring tens of thousands of horsepower at the
appropriate shaft speeds are in widespread use. Rather, it is because a Top
Fuel engine cannot be run at its maximum power output for more than about 10
seconds at a time without overheating (or perhaps exploding) as would be
necessary to take a reliable power reading. Instead, the power output of the
engine is usually calculated based upon the car's weight and its
performance. The calculated
Power<http://en.wikipedia.org/wiki/Motive_power>output of these
engines is most likely somewhere between 7000 and 8500
horsepower <http://en.wikipedia.org/wiki/Horsepower> (approximately
4500-6000 kilowatts), with a torque
<http://en.wikipedia.org/wiki/Torque>output of 8135 N·m (ca. 6000
lbf·ft <http://en.wikipedia.org/wiki/Lbf%C2%B7ft>) and a brake mean
effective pressure <http://en.wikipedia.org/wiki/Mean_effective_pressure> of
80–100 bar (8.0-10 MPa).

For the purposes of comparison, a 2008 SSC Ultimate
Aero<http://en.wikipedia.org/wiki/SSC_Aero>,
the world's fastest production automobile at the time, produces 1,183 bhp
(882 kW) horsepower and 1094 lbf·ft (1483 N·m) torque, and the calculated
horsepower of a top fuel dragster's supercharged V-8 engine easily surpasses
that of the largest aviation piston engine ever conceived, the Lycoming
R-7755 <http://en.wikipedia.org/wiki/Lycoming_R-7755> 5,000 hp (3,700 kW),
36-cylinder multibank (nine sets of four cylinders inline in each bank)
engine from 1946, which had over fifteen times the displacement of the
largest displacement top fuel engine.
[edit<http://en.wikipedia.org/w/index.php?title=Top_Fuel&action=edit&section=5>
] Engine weight

   - Block with liners 187 lbs (85 kg)
   - Heads 40 lbs (18 kg) each
   - Crankshaft 81.5 lbs (37 kg)
   - Complete engine 496 lbs (225 kg)

On Tue, Oct 13, 2009 at 7:20 PM, <wkooiman at earthlink.net> wrote:

> What is the a/f ratio for nitro dragsters?
>
> Isn't 70cc of air vs. 2cc of fuel 35:1?
>
> If this were gasoline, wouldn't it be closer to 70cc of air with ~5.5cc of
> fuel?  (about 12:1)
>
> Since this is nitro, wouldn't it be closer to maybe 70cc of air with 20cc
> of fuel?  - or even more fuel?
>
> -----Original Message-----
> >From: Thomas Tornblom <Thomas.Tornblom at hax.se>
> >Sent: Oct 13, 2009 1:19 PM
> >To: dave at damardirect.com
> >Cc: 'List Pantera' <detomaso at realbig.com>
> >Subject: Re: [DeTomaso] NPC- Definition of acceleration
> >
> >Dave McManus skrev:
> >> Ok, I sent the thread to my engineer super son-in-law for his 2 cents.
> He
> >> says he likes ACME rockets!
> >>
> >> IndyDave
> >>
> >> Here are his thoughts:
> >>
> >> His thought process is wrong as far as how he is looking at the volume
> of
> >> the engine.  500 cubic inches is not the volume of the cylinder, it is
> the
> >> displacement.  You would have to figure out how many cc the heads are.
>  You
> >> would then add that to the gap caused by the head gaskets times the
> diameter
> >> of the piston.  He may know this but he did not include it in his
> >> calculation.
> >
> >I know that I omitted the combustion chambers in my example. In my
> >hypothetical example I chose 500 cui as that is very close to 8 liters,
> >or one liter per cylinder, makes it simple to calculate :-)
> >
> >Normal Cleveland CC:s are on the order of 60-75cc, which is orders of
> >magnitude more than the amount of fuel needed in my calculation, and big
> >blocks normally have larger CC:s. There is thus no chance of hydro lock
> >for one missed spark, and most of the unburned fuel will be dumped
> >through the exhaust so I don't see how several missed sparks would
> >accumulate and cause hydro lock either.
> >
> >>
> >> Hydraulic lock also references that the mixture is incompressible.  So
> >> basically you are taking 3 Liter of nitro / air (1L/cylinder compressed
> at 3
> >> bars) and jam it a 1L cylinder. The cylinder goes through its combustion
> >> cycle and further compresses the mixture.  At TDC the volume of the
> cylinder
> >> is only the volume calculated above.  At some pressure point its easier
> for
> >> the rod to set sail than continue on the compression path.  The
> compression
> >> ratio is 6.5:1.  The pressure inside the cylinder is much higher than
> the 3
> >> bars.  I believe you can use pV=nRT from Thermodynamics here.  Thus,
> >> p1V1=p2V2.  That would mean the cylinder is at 19.5 bars or 280psi.  I
> am
> >> sure they are minimizing the cc's of the head to maximize power and the
> >> hydraulic lock would be the limiting factor.
> >
> >Yes, the pressure at ignition will be much higher, but that doesn't
> >matter. What matters is the amount of air you have shoved into the
> >cylinder, which happens to be 3 liters if you are running at 3 bars of
> >boost. No matter how much or little you compress this, the mass stays
> >the same, and thus the amount of fuel needed for stoichiometry. And I
> >calculated that to around 2cc. So you have 2cc of liquid, and 3 liters
> >if air crammed into a 70cc or so combustion chamber. Those 2cc:s are not
> >going to cause hydro lock.
> >
> >I'm willing to be proved wrong, but it would need some explanation.
> >
> >Rich fuel blends are frequently used to keep the internals cool, but it
> >appears to be orders of magnitude off, unless I've done some serious
> >thought error.
> >
> >There is no water injection on top-fuel dragsters, or? That would add
> >some liquid.
> >
> >>
> >> http://www.motortrend.com/features/112_0502_top_fuel_numbers/index.html
> >> Brandin Ray
> >> Forming & Shoring Design Engineer
> >> -----Original Message-----
> >> From: Göran Malmberg [mailto:hemipanter at hemipanter.se]
> >> Sent: Tuesday, October 13, 2009 3:35 AM
> >> To: michael at michaelshortt.com; 'Thomas Tornblom'
> >> Cc: 'List Pantera'
> >> Subject: Re: [DeTomaso] NPC- Definition of acceleration
> >>
> >> I believe we could say that the air is very much only a media for the
> >> supercharger to transport fuel in to the combustion chamber and not
> >> really for burning. At idle it is very rich and does literally shower
> >> out the exhaust. Another thing is that by using smaller diameter  and
> >> longer stroke we can make the engine act as a bigger than 8 litre. By
> >> using larger combustion chamber we can stuff more fuel in to it as well
> >> as if the diameter was larger.
> >> Goran
> >>
> >> -----Ursprungligt meddelande-----
> >> Från: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com
> ]
> >> För michael at michaelshortt.com
> >> Skickat: den 12 oktober 2009 23:07
> >> Till: Thomas Tornblom
> >> Kopia: List Pantera
> >> Ämne: Re: [DeTomaso] NPC- Definition of acceleration
> >>
> >> I don't know anything about all that math stuff, but I do know that a
> >> great
> >> deal of the air used in the "explosion" is contained in the fuel mixture
> >> itself ( like rocket fuel )
> >>
> >> And from having seen lots of them "blow up", they certainly do come
> >> apart
> >> with great explosive force, often removing the blower and scoop, heads
> >> and
> >> headers ( although nowadays they are held down by straps ) or they lose
> >> fire
> >> and dump loads of raw fuel out of the header pipe of the offending
> >> cylinder
> >> ( which you see on TV all of the time ). and sometimes the bottom end
> >> also
> >> comes apart ( and that's when all the action stops and the track has to
> >> be
> >> cleaned up ).
> >>
> >>
> >> Nothing else smells like Burnout tire smoke and Nitro methane, it smells
> >> like.............Victory!
> >>
> >>
> >> Michael Shortt
> >>
> >>
> >>
> >>
> >>
> >> On Mon, Oct 12, 2009 at 4:52 PM, Thomas Tornblom
> >> <Thomas.Tornblom at hax.se>wrote:
> >>
> >>> 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
> >>>>>>
> >>>>>>
> >>>>>> This email is protected by the Electronic Communications Privacy
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> >>>>>> that any retention, dissemination, distribution or copying of this
> >>>>>> communication is strictly prohibited.  Please reply to the sender
> >>>> that you
> >>>>>> have received this message in error, then delete it.  Thank you
> >>>>>> _______________________________________________
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> >>>
> >>> --
> >>> Real life:   Thomas Törnblom             Email:
> >> Thomas.Tornblom at Hax.SE
> >>> Snail mail:  Banvallsvägen 14            Phone:    +46 18 444 33 21
> >>>              S - 754 40 Uppsala, Sweden  Cellular: +46 70 261 1372
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> >Real life:   Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
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-- 

Michael L. Shortt
Savannah, Georgia
www.michaelshortt.com
michael at michaelshortt.com
912-232-9390

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