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In the days of great American cubic inches of muscle, the
hemispherical combustion chamber was not original even in
the engine we revered, the Hemi. The very first hemispherical
combustion chamber on record, with a pair of valves at
an included angle to allow them to seat in the sides of the
dome, was introduced by the Belgian company Pipe
Construction Automobile in 1906. In all fairness, further
development has occurred in the succeeding
century, but the name that
made Chrysler's V-8 famous
was not exactly new technology
even in 1951.
As Bob Joehnck told
us in our Vol II, No 4,
"An engine is an air
pump; you have to get
it in and get it out
the quicker the better." By
the time the NASCAR 426 Hemi had
become a household word in American race-fan
home, it was pumping at about 36.5 cubic yards of atmosphere
every minute. Combustion and emission challenges
became the issue and contributed to the end of the big-block
muscle car era but not, as it turns out, of the quantifiable
performance levels we had come to love.
Everything we lost of the five-pound coffee-can piston,
the multiple toilet-bowl carburetors, and the second-story
gutter-pipe intake manifold has been returned with electronic
engine management, metallurgy and mass-flow science.
The modern Hemi that has re-established DaimlerChrysler's
Chrysler Group as America's volume street performance
leader has matched the horsepower of its grandfather.
Not only is the Dodge Magnum SRT8 not your grandfather's
station wagon, it is a modern utility vehicle of very
serious sport. Dr. Z and Mr. Creed (global chairman and US
design director of the firm) have decreed it a "sports tourer."
Think Ferrari for five with the soul-stirring sound in a
lower octave and torque.
Chrysler has still done the American thing, much like
GM with their LS7, two valves and pushrods yes: but with
a billet camshaft high in the block; short, light push rods
and light-weight, hollow-stemmed valves (the exhaust
valves contain sodium that quickly carries heat out of the
head), with enormous, short ports and long curved runners
to replace the gutter-down pipes and hood holes of the
ProStock era. SRT's new Hemi intake system has improved
gas flow from the standard production Hemi, and includes
sequential multi-port fuel delivery and twin-plug ignition
that was developed in a private race shop all those years
ago. All that simple technology not only slams the piston,
and its powdered-metal connecting rod, back down the hole;
it leaves almost nothing unburned before the hot gas is
shoved into the heat-shielded headers. California (even)
awarded it a LEV 1 for ultra low emissions.
Getting a grip on the 425 horsepower and 420 lb-ft of
torque are twenty-inch Goodyear Eagle F1 tires developed
for continuous high speed Z rating. They are different front
(P245/45R20) and rear (P255/45R20). To arrive at 60 mph
in a tick over five seconds requires enormous grip when you
are trying to get 4260 pounds of family hauler haulin'.
Ever since Daimler and Chrysler linked names, the
enthusiast culture has dreamed of a line of affordable cars
with chassis dynamics from the brilliant resources once
directed by rennsport όber wissenschaftler Rudolph
Uhlenhaut. They have arrived. Rear wheel drive, long in
development by Daimler Benz as safe and secure while
including grip, and grace at the edges of high performance
slip angles, was followed by Mercedes-Benz' famously
effective five-speed brain box that consistently delivered
the engine's most useful rev range as an immediate response
to the driver's right foot. Now the suspension bits and
alps-and-autobahn chassis dynamics have changed the
targets around Chrysler's half-century-old Chelsea Proving
Ground track.
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