New Polaris RZR Pro R Boost Packs 275 HorsepowerPolarisPolaris's new turbocharged 2.0-liter inline-four makes 275 horsepower and 233 pound-feet of torque, making it the most powerful engine in the side-by-side world.Nearly every other driveline component has been beefed up to handle the new power.The 2027 RXR Pro R Boost arrives at dealers in November with a starting price of $49,999.Is there an end in sight to how much horsepower in the high-performance side-by-side world is enough? We hope not, and Polaris doesn't think so. The grand-daddy of hi-po utility vehicles and its 2027 RZR Pro R Boost has just raised the bar—and the manifold pressure—in the off-road King of the Ring horsepower battle.The Pro R is motivated by a 225-hp naturally aspirated 2.0-liter inline-four. Enter the Pro R Boost, enhanced by, you guessed it, a turbocharger. And a rather large one. A 66-millimeter Garret turbo stuffs the intake plenum with a charge cooled by a liquid-to-air intercooler. At full tilt, the boosted 2.0-liter generates 275 horsepower and 223 pound-feet of torque, and Polaris claims the engine will not derate until ambient temps are over 115 degrees or when riding above 10,000 feet of elevation.PolarisThe amount of horsepower easily moves the Pro R Boost to the top of the segment, where it topples the Can-Am Maverick R's 240 horses and the Kawasaki Teryx H2's 250 ponies. And though horsepower makes headlines, the Boost's torque output cripples its direct competitors. The Polaris churns out 223 pound-feet at 6000 rpm and even crosses the 200 mark at roughly 3300 rpm. In comparison, the Kawi tops out at 146 pound-feet at 8800 rpm and the Can-Am at 170 pound-feet at 6000 rpm. In all, the Pro R Boost should have a more usable powerband.AdvertisementAdvertisementNaturally, there's more cooling to keep things, well, cool. There's now a radiator mounted behind the occupants for engine cooling, and it's fed air by a roof scoop. Nearly every driveline component has been touched. The clutches of the continuously variable transmission are reworked, and the driven clutch, spun by a stronger belt, is larger in diameter with more cooling fins. The half-shafts are stronger and the front differential features meatier components that no longer force Polaris to limit torque to the front axle. Despite the Pro R Boost carrying an additional 200 pounds, according to Polaris, the 50-hp bump still returns a meaningful weight-to-power ratio.When the Pro R Boost arrives at dealers in November, it'll carry a rather hefty price tag. The two-seat Ultimate starts at $49,999 while the four-seat version kicks off at $53,999. Moving up to the Ultra adds active anti-roll bar links to the Ultimate's adaptive dampers, a carbon-fiber hood and seat bezel, nicer steering wheel, and 32-inch BFGoodrich tires. Two-seat versions start at $52,999 and $56,999 for the four-seater.➡️ Skip the lot. Let Car and Driver help you find your next car.Shop New Cars Shop Used CarsYou Might Also LikeGift Guide: Best Ride-On Electric Cars for KidsFuture Cars Worth Waiting For: 2025–2029