Nels Eide: Hey everybody, welcome back to another episode of Sled Tech! In today's episode, we're going to be talking about the 9R, our factory mod big bore engine.
Here at Polaris, we love building two-stroke engines. And what's not to like? They sound awesome, they're lightweight, they make a ton of power, and they just rip. The 9R is our ultimate pure two-stroke performance, and we really enjoyed building it. This engine comes from the racetrack; this is our 900 Improved Hill Climb package that meets emissions and sound regulations for production. But this is what Keith Curtis, Andy Thomas—what our Hill Climb team—raced on the race course in the 900 Improved class for a number of years, now brought into production.
The 900 Improved class is essentially 900 Open Mod, but with no turbos, superchargers, or power adders, so it's naturally aspirated, pure two-stroke performance. The response that the hill climb team was looking for, mixed with the power, was exactly what backcountry riders were looking for when we took it out into the backcountry. Not everyone, but when you want to ride super tight, technical terrain and steep trees, you need that lightweight response to get the engine spun up quick and get going. You're also making really tight maneuvers from a handling perspective, and you don't want a lot of weight; you want something light, quick, and easy to handle. When we looked at what the two groups were looking for and what we had on the racetrack with our 900 Improved package, the backcountry riders were looking for the same thing. The benefits were there, and that's where the production 9R program was born—taking what was winning so many races and a ton of money on the racetrack and putting it into production so we could get it to the backcountry riders as well.
The foundation of the 9R is a Patriot 850. When I said earlier that this is the 900 Improved version of our 850, that's exactly what it is. The engine started life as an 850, and then all of the "mod" parts that we put in it are what make it work so well. It starts with the crank, which gets a lightweight crank and a lightweight flywheel. It's 10% lighter overall than an 850, and that's about a 3% reduction in inertia. That might not sound like a lot—3%—but when we talk about inertia in the drivetrain, that's the most valuable inertia gain in the entire vehicle. On an RMK, when you're making those tight, technical maneuvers, you're actually steering the vehicle with the track. What I mean by that is you rev the engine up, you spin the track, and that's what lets you manipulate the track in the snow because the track is already moving. In order to make those really quick adjustments, you've got to get the track spinning really quickly. To do that, you've got to have a low-inertia engine to help drive the vehicle forward. The 9R has that lightweight crank, which offers a ton of response benefits. It's noticeably snappier, gets revved up, and gets moving quickly, making it the sled to have in those tight, technical backcountry events.
Moving up from the crankshaft, we go to the cylinders and the pistons. So, it is a big bore. It still has a 74mm stroke, just like the rest of the Patriot platform, but the 85mm bore goes up to 88mm here for the 9R. So, it's 899cc, a full 900 for the improved class. It also features special pistons. Obviously, these are wider pistons to fill the bore, and they have a ceramic coating on top just to help with the heat and the load of the more power and faster response. Again, ceramic-coated pistons are mod parts that we are now putting into production and selling in SnowCheck.
The last piece of performance tech on the 9R is the ports. It starts as an 850 from the 850 platform, and then it's actually CNC-machined ports on both the exhaust and intake side, really just like a mod sled. This allows for more flow, more power, and delivers that response and power that the 9R has. And that's really it. When we say that the 9R is built from the 850 platform, we really mean it. It's largely the same components; it's very similar architecture—literally just a big bore 900 improved version. We did a video on the 850 Patriot and really the Patriot platform, so go and check that one out as well. But that's really where the 9R comes from and how we built it: as a big bore 850.
When you put all that together, you get the best naturally aspirated two-stroke we've ever made. It makes 7% more horsepower than an 850 and 13% more torque, and it is the quickest-responding, fastest-revving, rip-roaringest engine we have ever built. When you put it in a mountain sled and you want to go ride tight, technical terrain, this is the absolute ultimate engine to have.
We also have another engine in our mountain sleds, the Patriot Boost, that we'll do a video on as well. The 9R and Boost are really the perfect pair. They are very different and do very different things. Obviously, Boost compensates for altitude as it goes up, maintaining power and building huge horsepower, but it's a little heavier, it's turbocharged, so the response isn't as quick as naturally aspirated, and it's really geared toward big-time terrain, super deep snow, and big hill climbs where you want massive amounts of power with zero trade-off. The 9R is the awesome complement to that; it's quick, super lightweight, and fast-responding for technical terrain. It's really a "pick your poison" situation—each one is the perfect engine depending on what you want to do, how you like to ride, and how you want to attack the backcountry.
And that's our 9R factory mod. We brought the 900 Improved motor in. We've been beating the yellow and green guys for years and thought, "You know, our mountain riders would probably like to have a chance at riding this engine as well." It's a SnowCheck exclusive, so next spring, make sure you get on the list and get one of these in your garage. That's all for today. Thanks for watching, we'll see you next time!
