Suzuki DF150 - Manual (Page 4)

3
Torque Curve
■ Advanced Technology for the
Performance
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 150hp (110kW) and 175hp (129kW) respectively.
At 2,867cm
3 (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 the
lightest in their category to date.
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 of four-stroke technology.
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 momen-
tary 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.
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 mani-
fold 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. Shorter 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.
* At the comparison test, Multi-Stage Induction System of the
motor was operated.
T
ORQ
UE
LOW MID
ENGINE SPEED
HIGH
with VVT
without VVT
T
ORQ
UE
LOW MID
ENGINE SPEED
HIGH
Torque
(without Multi-Stage Induction)
Torque
(with Multi-Stage Induction)
Air Flow in Multi-Stage Induction Module
Torque Curve
Lower rpm High rpm