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Largest
Displacement in Their Class
The new DF150 and DF175 utilize
an all-new inline four-cylinder four-stroke engine
with a DOHC four-valve powerhead that produces
150ps (110kW) and 175ps (129kW) respectively.
At 2,867cm3 (174.9 cu.in.)
these two outboards offer the largest displacement
in the four-stroke,
four-cylinder category to date. And thanks to
Suzuki’s innovative engineering, they are
designed as the compact and lightweight outboard
motors.
VVT
(Variable Valve Timing) (DF175)
In designing the DF175, our goal was to expand the potential
of the four-stroke engine and create an outboard that delivers
high performance along with the benefits that four-stroke technology
provides.
Like the flagship DF250, the DF175 is designed with an aggressive
cam profile and paired with Suzuki’s advanced Variable
Valve Timing (VVT) to increase the low to mid-range torque
outboards need when accelerating. The intake valve actually
starts to open before the exhaust valve fully closes, creating
a momentary overlap in the timing where both valves are open.
Using Variable Valve Timing, this overlap can be increased
or decreased by altering intake timing with the camshaft, thereby
optimizing camshaft timing for low and mid-range operation.
Torque
Curve
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At the comparison test, Multi-Stage Induction
System of the motor was operated. |
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Multi-Stage
Induction (MSI)
The DF150 and DF175 incorporate a multi-stage induction system
to enhance engine performance by changing the length of intake
manifold pipes according to engine speed. The system utilizes
two intake manifold pipes per cylinder, one for operating at
low engine speed and another for operating at high. At lower
rpm, air enters the combustion chamber through the longer manifold
pipe, which is designed to deliver an optimum volume of fresh
air into the chamber to improve combustion and boost low-end
torque.
As the engine speed surpasses a
preset threshold, the valve on the direct intake pipe
opens up letting air enter instantly
into the combustion chamber. Short and lacking resistance this
pipe gets a greater volume of air into the chamber, increasing
the engine’s ability to breathe at high rpm, thus improving
high speed power output.
Suzuki engineers have equipped these outboards with many other
advanced features that contribute to engine performance.
A spherical bore throttle body produces smoother airflow during
acceleration. This results in greater engine control and stable
operation at low rpm.
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Air Flow
in Multi-Stage Induction Module
Torque
Curve
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Counter
Balancer System
In-line four-cylinder engines operating
at high rpm generates a secondary vibration that
is directionally in line with the piston’s
movement. In order to counter this vibration, Suzuki
engineers utilize a secondary balancer system, which
produces a horizontal motion against piston’s
movement. To produce this horizontal motion, the
balancer is divided in to left and right sections
each rotating in an opposite direction. Rotating
at twice the speed of the crankshaft, the balancers
effectively counter these secondary vibrations and
produce a smoother operating engine.
Offset
Drive Shaft
First introduced in the DF90 and 115, Suzuki’s offset
driveshaft has proven successful in reducing the size of the
outboard in the DF140, DF200, DF225, and DF250. The DF150 and
DF175 benefit from this same design, which positions the crankshaft
in front of the drive shaft simultaneously moving the outboard’s
center of gravity forward. While adding to the compactness
of the outboard and providing an improvement in power performance,
this system also places the engine’s axis of inertia,
the point where vibrations produced by the engine are at a
minimum, up over the upper engine mount thus greatly reducing
vibration.
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Offset
Drive Shaft
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Suzuki’s
Anti-Corrosion Finish
Suzuki’s
anti-corrosion finish is specially
formulated to increase the durability
of the engine and protect those parts
of the aluminum exterior that are constantly
exposed to saltwater. Applied directly
to the outboard’s aluminum alloy,
this advanced finish provides maximum
bonding of the outboard’s finish
to its aluminum surface. Layered on
top is an epoxy primer undercoat, black
metallic finish, and clear acrylic
fiber finish that together, form an
effective treatment against corrosion.
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