The RZR XP 900 XP is packed with
their ProStar 900 EFI Twin. This is not
the same powerplant found in the
Polaris Sportsman 850. In fact, it’s the
first motor in the market that was
specifically designed for a UTV. This
875cc dual-overhead-cam (DOHC)
engine is located behind the seats
and uses four valves per cylinder to
put nearly 90 horsepower (a claimed
88 hp) to the wheels.
The new motor also runs parallel
with the chassis (RZR 800 is perpendicular) and uses an 180-degree
crankshaft to bring power to the
wheels. The RZR 800 power is ran
through a series of 90-degree angles.
Aside from having a 125cc larger
powerplant than the RZR 800, the XP
has better throttle response, accelerates quicker, runs quieter and
requires less maintenance. Sounds
Fuel is fed from the 7.5-gallon fuel
tank through electronic fuel injection
and dual-throttle bodies—the same
EFI setup that has been running flaw-
lessly in Ranger RZRs since 2008.
Air is filtered via a large rectangu-
lar K&N-style air filter, which is oddly
located in the rear bed compartment.
Every other UTV’s filter is found in
front of the machine, which is ideal
for airflow. Polaris was able to do this
by designing an airbox system that
incorporated dual vents on each side
of the bed. Each vent has its own
foam filter that is easily removed for
cleaning. After six hours in the heavy
dust, the side vents had slight dust,
but the main interior filter had only
small specs of dust.
WAS IT FAST ENOUGH?
Woooooo! As soon as your right
foot touches the gas pedal, you’re
already a mile down the trail. The
throttle response is the quickest
we’ve tested, and you’re never ask-
ing for more power. Seventy-mph-
plus in a UTV is as fast as we want to
go, but speed junkies will easily have
the XP in the mid to high 80 mph.
We’ll soon get a chance to conduct
a shootout of the RZR XP against the
Commander 1000, but to give you an
idea, we joined William Yokley in his
XP 900 racer at the first WORCS
round in Taft, California (check page
78). The National Guard-sponsored
RZR XP 900 took the holeshot over a
modified RZR 800 and Can-
Am/Motowork’s Commander 1000
UTV. Our flat tire kept us from further
comparisons, but we’ll have a com-
plete shootout in the months to come.
TROPHY TRUCK SUSPENSION?
The Polaris RZR XP 900’s stance is
between the RZR S and RZR 4. Its
wheelbase is 81. 4 inches, compared