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"The all-new 2.4-liter turbocharged
World Engine delivers a level of power you'd expect from a V-8,"
said Pete Gladysz, Senior Manager – Powertrain, SRT. "With the
engine in the all-new 2007 Dodge Caliber SRT4, we were able to take
advantage of tried-and-true performance improvements, such as
increased cylinder-head flow and higher compression ratio, as well
as newer technologies such as Variable Valve Timing (VVT)."
To achieve its high-performance Dodge
Caliber SRT4 configuration, the aluminum 2.4-liter World Engine
block is specially machined for increased water and oil flow. Unique
cast pistons travel within iron cylinder liners, and are cooled by
oil squirters and affixed to forged connecting rods for high-revving
reliability.
Tri-metal bearings are used for the
connecting rods and crankshaft for high-performance durability. A
unique oil pump/balance shaft module keeps the reciprocating
assembly well-lubricated and running smoothly. An external cooler
keeps oil temperatures within a safe range.
The aluminum cylinder heads are
also a World Engine casting equipped with unique high-temperature
exhaust valves. VVT uses computer mapping to open and close intake
and exhaust valves at optimal points for efficient combustion and
flow. The camshaft and micro-alloy steel crankshaft, shared with the
non-turbocharged 2.4-liter World Engine, are fully capable of
high-horsepower loads.
Free-flow induction begins with an
all-new air cleaner assembly that draws through an opening in a
front crossmember for proximity to cool air. The air is then
compressed in a TD04 turbocharger specially configured for the
engine's inlet and outlet packaging requirements, and sent through
an intercooler to a 57 mm throttle body.
Fuel is provided by a high-flow
pump feeding injectors developed specifically for the 2007 Dodge
Caliber SRT4. An all-new engine management system designed by
Siemens — the Global Powertrain Engine Controller — keeps the
powerplant running at maximum efficiency and power.
On the exhaust side, spent gases
exit through a free-flow system that features two catalytic
converters — one immediately downstream from the turbo, and another
further along the 3-inch single-pipe exhaust system. Using two
catalytic converters in this way provides significantly better
"light-off" for decreased emissions. As with the previous-generation
Dodge SRT4, the exhaust is tuned for maximum performance while
meeting federal noise regulations.
Power is transferred through a
dual-mass flywheel to the six-speed manual transmission. The
dual-mass flywheel consists of two flywheels sandwiching internal
springs that are specially tuned to reduce noise and vibration. The
GF DMT-6 six-speed transmission, equipped with a limited-slip
differential for uniform side-to-side power transfer, is capable of
handling up to 300 lb.-ft. of torque.
Torque is sent to the Dodge Caliber
SRT4's wheels through equal-length halfshafts sourced from Chrysler
Group mid-size cars for their larger size and power-handling
capability. |
