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Evolution 4 was launched in August
1996 and was big change to previous
Evolutions being based on the
entirely new chassis and bodyshell of
the 5th generation Lancer.
While the 4G63 power plant was
retained, it underwent extensive
modifications. In addition to the use of
a high-speed cam profile and lighter
pistons, Evolution 4 reduced turbo lag
by minimizing gas flow interference in
the exhaust manifold. The introduction of a twin-scroll turbocharger (TD05HR-16G6-
9T) improved turbo charging performance, generating more torque in the low and
medium range.
Evolution 4 also featured a straighter
intake manifold, and a metal head
gasket that withstood the higher
compression ratio and boost pressures
better. The introduction of a
secondary air induction system
improved turbo on-off response by
feeding pressurized air above the
turbine and reducing negative
pressure, thereby keeping turbine
speed from dropping under
deceleration. All this new technology
realized a substantial increase in
engine performance, pushing
maximum power output up to 276bhp
at 6,500rpm and maximum torque to
260lbs/ft at 3,000rpm.
The engine was rotate 180degrees
and could accommodate a much larger
transfer box. The cylinder head and
parts of the engine block were
machined thinner to reduce weight.
In addition to the standard close-ratio
5-speed manual transmission,
Evolution 4 was offered with a superclose-
ratio gearbox in RS trim. And a
choice of high or low final drive gears
made Evolution IV easier to tune for
competitive use.
Braking was improved with the use
large ventilated discs on the GSR and
ABS was fitted a standard.
Lancer Evolution 4 WRC History
The RS model, developed primarily as
a base vehicle for competition use,
was offered with a torque-adaptive
helical gear limited slip front differential
- a world first on a 4WD model. And on
the GSR the rear differential
incorporated another world first: Active
Yaw Control.
Generating a stabilizing yaw moment
by creating a torque differential in the
rear wheels, AYC realized a significant
improvement in cornering performance
and in vehicle stability under hard
braking.
Externally the car was styled for
efficiency rather than cosmetics,
making Mitsubishi’s WRC intentions
for this car clear. The Evolution 4 was
fitted with a new front bumper, front
airdam with large foglights, revised
side skirts and rear splitter. A larger
delta shaped rear wing was fitted and
the bonnet air outlet enlarged.
Evolution IV saw a shift towards more
on-road testing during development,
enabling it to evolve into a machine
capable of showing the opposition just
as clean pair of heels on the circular
track as in rallies.