COMPARISON / BIG BORE SHOOTOUT
Arctic Cat ZR 858 Sno Pro 129 Polaris Patriot 9R Indy XCR 136 Ski-Doo MXZ Adrenaline with Blizzard Package 850 E-TEC 137
That allows Cat to place the engine lower and deeper in the chassis than some competitive designs .
The engine also has many cutting-edge features , including a revolutionary variable exhaust design and new VForce reeds . Beyond that , designers went to great lengths to strip weight and keep the engine physically small . Cat isn ’ t claiming any specific horsepower number , instead opting to just say it creates 11 percent more giddyup throughout the powerband than the previous 800 twin .
Power goes through Cat ’ s third-year ADAPT clutches and then through a final belt drive that ’ s unique in trail sleds .
As mentioned , the Patriot 9R engine wasn ’ t new , but it is available for the first time to flatlanders . It ’ s based on Polaris ’ 850 Patriot twin , but it has a larger cylinder bore plus a lightweight / low-inertia crankshaft and flywheel , ceramic-coated pistons , CNC-machined ports and a lightweight , high-flow exhaust system .
Like Cat , Polaris isn ’ t claiming a specific peak horsepower number with its so-called “ factory mod ,” but instead says the 9R creates 7 percent more horsepower and 12 percent more torque than the 850 Patriot , while building power more immediately than the turbo option .
An updated version of the P22 secondary was attached to the end of the spinning crankshaft .
In one of those “ time flies when you ’ re having fun ” tales , it ’ s hard to believe the direct-injected 850 Rotax in the Ski-Doo is entering its ninth season after being introduced in 2016 for model year 2017 .
The E-TEC-fed engine that Ski-Doo rates at 165 horsepower hasn ’ t had many changes over the years , but it hasn ’ t needed them . It has been a smooth-idling yet hard-hitting engine right off of clutch engagement since the minute it was introduced , with impressively long legs that ’ ll let it run with any naturally aspirated engine in the sport .
Power was sent through Ski-Doo ’ s pDrive primary clutch with traditional TRA-style clicker adjustments and then a QRS Vent secondary .
All three of these engines were responsive , mega-powerful and fun , but our test team was most drawn to the 9R from Polaris .
“ It has such an amazingly torquey feeling every time you engage the throttle , whether off a start , coming out of a corner , or even when you ’ re going 70 MPH and want to give
16 / JANUARY 2025 / SNOWGOER . COM