Polaris RZR XP 900
BEAMING, BRIGHT WHITE HEADLAMPS AND A HARMONIZING STACCATO OF FOUR-STROKE RUMBLE SERVED AS BOTH A RECEPTION AND A PROCLAMATION FROM POLARIS AS WE EXITED OUR AIR-CONDITIONED BUS INTO THE ARIZONA DESERT. NEWS OF A BIGGER, FASTER, AND MORE COMPETENT RZR HAD BEEN RUMORED FOR SOME TIME, AND GREW MORE INTENSIFIED AFTER CAN-AN UNVEILED THEIR LONG ANTICIPATED BIG BORE COMMANDER, OFFICIALLY MARKING THEIR ENTRANCE INTO THE SIDE-BY-SIDE ARENA.
Yetdespite those expectations, few if any were prepared for the “bigger hammer” Polaris that was about to drop. Even our competitive publishing counterparts who spend much of their time on the west coast of the United States, close to the dune and desert off-road scene, were unprepared for the “next-big-thing” RZR. Certainly Polaris had already secured ownership in the sport side-byside market by first one-upping the first to market Yamaha Rhino with the original 50-inch wide RZR. However, unlike other competitors, Polaris wasted little time knocking down subsequent barriers and gobbling up market share with a steady progression of performance and capabilities with the RZR-S and RZR-4.
With those moves, Polaris quickly found itself atop the UTV market. But like many rulers, leading is often never enough, and dreams of conquest followed. Enter the conqueror; the all-new Ranger RZR XP 900. From its wide 64-inch stance and whopping 13-inches of ground clearance, to its flared fenders and monstrous Fox Podium X shocks, the RZR XP makes a clear and defined statement of bigger and expectedly better. To the untrained eye, the RZR XP looks very similar in many ways to last year’s restyled RZR.
In fact, the plastic, save the oversized fender flares, along with interior decor is identical to other RZR models; but that’s where the similarities end. Perhaps ripping a page from the Shuar tribes of South America, best know for their tribal custom of head hunting and head shrinking, Polaris engineers determined their vehicle of conquest would need to incorporate off-road suspension technology from the most adept off-road vehicles in the world – trophy trucks. With suspension travel rated at 14-inches at the rear and 13.5-inches at the front, the RZR XP touts a suspension stroke that bests nearly every aftermarket suspension currently on the market, let alone stock OEM competitors. TROPHY TRAVEL To gain such numbers of suspension capability, the RZR XP employs a threepoint rear suspension that in many ways mirrors a trophy truck, right down the over-sized FOX Podium X 2.0 shocks. It’s the rear suspension that almost immediately catches your eye, thanks to a long and extremely beefy trailing arm that attaches to the chassis just behind the cab and extends to the rear wheel.
Two adjoining radius rod control arms perside, keep the position of the rear axle in place as it strokes a full 14-inches of vertical movement. The new trailing arm rear suspension features a long and very stout “trailing” link that affixes itself to the new chassis beneath the cab. You can see the shock mounting tab located mid-way back on the arm. It’s the long, oversized trailing arm that allows the system to deliver huge travel numbers, while at the same time having the strength to withstand terrain of even greater vertical breadth. In a more traditional upper and lower control arm system, such as the one used on the RZR-S, terrain forces experienced by the control arms, as well as the central mounting location, attempt to twist and exert force on the suspension in a horizontal fashion.
The control arms and mounting location must be strong enough to redirect these forces into vertical travel. In order to do so, the system first needs to be incredibly strong and subsequently heavier. In addition, travel numbers are limited due to packaging, design, and the horizontal forces experienced. The three-point “trophy-truck” design used on the RZR XP allows for more travel, and at the same time, ease of packaging. The massive FOX Podium shocks found here would never fit within the confines of the RZR-S rear suspension.
There are trade-offs of course. While handling attributes associated with camber can be design altered for desired cornering results, the large travel numbers also creates greater amounts of wheel scrub, a trade-off Polaris engineers claim is worth the handling benefits the RZR XP exudes; more on this later. To the front, a more traditional, dual Aarm design resides, albeit a very tall one. With another pair of remote reservoir Podium X shocks found here, with the same pre-load and compression damping adjustments, travel is just south of 14 at 13.5-inches (34.3cm). Those travel numbers coupled to 27x12 ITP tires standing at a full 64-inches (162.6cm) wide, and you have 13-inches (33cm) of ground clearance, giving the RZR XP the ability to drive over more terrain that others simply can’t. The front of the new RZR XP touts a broad spoiler which is said to not only improve aerodynamics, but also eliminates dead air pockets within the wheel well, thereby improving shock cooling as well.
The new engine was purposely positioned with a forward exiting exhaust so its length and routing could be tuned for optimum power. The stainless-steel, two into one plumbing dumps into an oversized, rear mount silencer that keeps the note hushed but leaves enough meat on the bone to alert would be rivals that there’s juice lurking within. We were greeted by a red RZR XP walkway upon arriving to our ride destination in Arizona this past January. The new Prostar engine and accompanying RZR XP transmission are adjoined by a spider casting, and mounted into the new tube chassis as a single unit, thereby keeping the center to center CVT distance constant for improved performance and belt life. You can easily see the wider and taller stance of the RZR XP when compared to its now smaller sibling RZR-S. PODIUM POWER Phase two of project shrunken trophy truck was undoubtedly more power.
It was widely known the current motor found in the RZR-S and RZR-4, while certainly competent, was also nearing the limits of its performance capabilities. Even the aftermarket world was admittedly, overextending the limits of the 760cc twin with big bore, high flow engine kits or turbo-charged performance boost; many which produced peak power numbers still south of the all-new Prostar 900. According to Polaris, the new RZR XP mill was designed and built specifically for a performance side-by-side application, although we suspect we’ll soon find this motor in other Ranger applications in the very near future. The dual overhead cam engine features 180-degree crankcase architecture, and when joined by a front, side mounted counter-balancer; it produces remarkably smooth power for a big bore twin. All the expected performance goodies are found on the new Prostar engine, including high flow head porting, optimized intake and exhaust flows, and an overall simplification in design.
The fuel injection system draws its oxygen charge through large 46-millimeter throttle bodies, which suck vapors through a new high volume air box, and oversized airfilter that according to Polaris, provides 90- percent more surface area over their previous design. The result is more air –charge at the ready when the accelerator is mashed, and less filter maintenance, especially in highdust and dirt conditions. With more flow coming in, engineers had to ensure more flow was also going out. For that reason, the new motor is mounted within the RZR XP chassis with a forward exiting exhaust. This gave powertrain engineers the space and exhaust pipe length to tune the exhaust flow for optimum performance. Visually, the Prostar engine sits tall, with a large dry-sump lower case and excessive head and valve train areas. Despite these visual cues, the engine is a ripper; pumping out a claimed 88-ponies at peak rpm.
Polaris is also quick to point out that the new engine delivers a dynamic 100-ponies per liter of displacement, which in layman’s terms means the engine is both efficient, and based upon our oneday rally, has plenty more power lurking, waiting to be uncorked by some simple aftermarket modifications. Joining the new Prostar power is an allnew transmission that features no “rightangled” transfer of power.
All gears in the new tranny rotate in the same direction, again for efficient power transfer. And the tranny is fed the goods from the Prostar 900 by updated drive and driven clutching that is borrowed directly from the Polaris snowmobile division, which is well versed in capturing power in excess of 150- ponies through CVT technology. With full CVT shift coming at 8750rpms, the new Prostar spins at nearly 2,000 revolutions more than the RZR 800. Even with these additional revs, we think there is way more power to be “uncorked” from the Prostar, and Polaris could very well be holding the new twin back for year-one.
Full size primary and secondary clutching components were borrowed directly from the well-versed Polaris snowmobile department. Out of box calibrations are excellent. Accessories for the new 900 are plentiful and hit dealerships in unison with the first delivery of RZR XP side-by-sides. From skid plates and bumpers, to LED light bars and high-performance stereo systems, the PURE division of Polaris has been hard at work as well, in preparation for the launch of the 900 XP.
The rear cargo box of the RZR XP has some new shapes associated with it, allowing for easy access to the air filter as well as this engine oil compartment. Details weren’t left out with the new performance XP. Included in the tool kit is this handy oil catch that keeps oil off the engine while changing the filter and its associated spooge of crude.