Arctic Cat Unveils 858cc Twin, High-Tech Gauge For 2025

Arctic Cat engine
The new 858cc Arctic Cat engine was shown to the snowmobile media at the factory in St. Cloud, Minnesota, where it will be built.

The large-displacement engine that Arctic Cat snowmobile fans were awaiting for the Catalyst chassis was unveiled today. The low-slung 858cc twin-cylinder two-stroke was shown at the massive Hay Day event in North Branch, Minnesota, on September 9.

     Cat officials say the new engine makes 11 percent more horsepower throughout its powerband than the 800 twin it replaces.

     Equally important, the Cat engineers stressed, the laydown architecture and the way it mounts in place is specifically designed for the Catalyst chassis. That will enable riders to take full advantage of the lightweight chassis and its centered masses that made first-year 2024 600-class Catalyst sleds so fun to test ride last spring.    

     The good news: The engine will be available in trail, crossover and mountain sleds in the Catalyst chassis. And the bad? You’ll have to wait until model year 2025 machines to experience it.

     Arctic Cat also unveiled a new high-tech gauge that’ll be available on 2025 models. Dubbed the Arctic Cat G8 Powered by Garmin, it features the sort of on-screen mapping, phone connectivity, group ride capabilities and more that have been available from competitive brands in recent years but not Arctic Cat.

The New Arctic Cat Engine

Arctic Cat engine
The new 858cc twin keeps Cat’s laydown design, with intake and exhaust on the same side of the engine.

Cat made a monstrous splash at the 2022 Hay Days event when it unveiled its long awaited new chassis platform. The Catalyst has been a huge attraction, but the 600-class powerplant it was unveiled with was a bit of a disappointment to many. Right at the chassis’ release, though, Cat officials pledged publicly that a larger displacement two-stroke was in development.

     Now unveiled, it uses the same 85mm cylinder bore but a longer, 75.6mm stroke than the engine it replaces. That allows it to reach its 858cc displacement.

     Like the 600 and other modern Arctic Cat two-strokes, it features a lay-down design with both intake and exhaust pointed toward the driver/center of the chassis. Cat engineers have long said this design allows the brand to better center masses in a chassis.

     This new 858, though, also mounts 3/8 of an inch lower in the chassis than the 600. The key is a new crankcase with integrated engine mounts. The reed cage was also moved 12mm closer to the cylinders. That improves airflow while also allowing room for the centerline steering system that is one key to the Catalyst design.

Arctic Cat reeds
The new Arctic Cat 858 engine will utilize VForce reeds that will mount closer to the cylinders for better airflow and also due to space constraints.

     Also unique is a new variable exhaust system with a push-pull actuator that is controlled by a servo that gets its directions from the sled’s ECM. That allowed it to be fully tunable for both performance and emissions, according to Troy Halvorson, Arctic Cat’s director of snowmobile product strategy.  He said it provides 250 percent more exhaust port height change than the previous design, allowing it to be nice and tight on the bottom end yet very free flowing on top-end.

     The system is also light, he stressed. With the previous design, there are about 30 parts per cylinder in the exhaust valve system. That’s been cut in half.

     Stripping weight while maintaining durability continued to be a focus of everything tied to the Catalysts. This new 858 twin, Cat officials said, is about 4 percent lighter than the engine it replaces. It’s also lighter than the 600 twin already in the 2024 Catalysts. Weight was also taken out of the exhaust system.

     Cat officials wouldn’t release a horsepower number on the engine in discussions with the snowmobile media. Instead, they went back to their pledge of an 11 percent increase. That 11 percent is found throughout the powerband, they said.

Arctic Cat 858
A top-down look at the engine.

The New Arctic Cat Gauge

The Arctic Cat G8 Powered by Garmin will get the brand right in the middle of the action when it comes to high-tech touch-screen displays, connectivity and usefulness. It’s an increasing customer demand.

    “This has been something that we’ve been striving to get,” Halvorson said. “We wanted to work with Garmin because they are a very reputable brand and are one of the top companies with it comes to GPS technology.”

     The gauge works specifically with Arctic Cat’s CAN bus (Controller Area Network) system, Halvorson said, to give riders information on the snowmobile at a glance. Beyond that, on-screen trail maps, route planning and cell phone connectivity are included.

     You can also do group rides that track up to 20 riders in your crew, and connect via radio communication, Bluetooth and/or cellular connections.  

Arctic Cat Gauge
The new Arctic Cat G8 Powered By Garmin gauge will be be available on select model year 2025 machines, but it will be able to be retrofit to earlier Catalyst models.

Arctic Cat Talking Points

Below are the official talking points Cat officials released on their new engine. Everything from here down is straight from Cat:


Purpose-Built for the Catalyst Platform

  • The 858 engine was designed to optimize the Catalyst platform’s centralized design, so the rider is the active force providing more power with more precision and control.
  • The innovative laydown engine design places the intake and exhaust in front of the engine allowing for the industry’s best mass centralization and lower center of gravity that the rider can feel for incomparable maneuverability.
  • Improved exhaust valve and fuel system controls for increased performance and reduced emissions.
  • The design is based on decades of Arctic Cat innovation complemented by the ingenuity of the current team to ensure the engine components fit the Catalyst platform’s design. From working around the centerline steering to integrating components for weight reduction and increased performance, there were no compromises in building an engine that would take the Arctic Cat ride experience to the next level.
  • When designing Catalyst, Arctic Cat considered the different powerplants that would be housed in the platform. The brand-new 858 engine is an even lighter package with a lower center of gravity creating a better power to weight ratio for a unique ride.
  • Available across trail, crossover and mountain platforms.

Optimized Power in the Industry’s Easiest to Ride Package

  • Along with its innovative design to complement the Catalyst platform’s mass centralization, the 858 engine provides the right amount of horsepower for superior performance.
  • A new air intake system that is integrated into the platform maximizes airflow to the engine for more power output. Multiple secondary, under-hood inlets prevent snow ingestion and optimize performance in all snow conditions.
  • The new, patented exhaust valve design is the latest, most advanced in the industry. It stays tight to the piston as it moves and provides smoother exhaust port flow throughout a wider RPM range on both primary and auxiliary ports. It also provides seamless power and cleaner emissions.
  • Compared to Arctic Cat’s 800 engine, the 858 engine provides 11% more power and torque, providing quicker acceleration and a high top speed.

More Power with Lighter Weight for an Exhilarating Ride

  • With its integrated engine mounting design and new exhaust system, the 858 engine is 4% lighter in weight than the current 800engine. It’s also lighter and provides a lower center of gravity compared to competitive engines.
  • A lighter weight design coupled with the Catalyst platform’s centralized mass and low center of gravity provides easier and more-precise handling for a ride experience like no other.
  • To keep a lightweight, compact size for the Catalyst platform, Arctic Cat used an 85mm bore while increasing to a 75.6 stroke to achieve more horsepower and deep, bottomless torque that pulls hard and smoothly through the entire RPM range. The result is a power-dense, easier to ride package.
  • The 858’s power-to-weight ratio coupled with the unique, lightweight Catalyst platform design takes carving through deep snow, maneuvering tight trails and boondocking to the next level.

Durable and Reliable to Spend More Time on the Snow

  • The Catalyst platform was designed to be durable and easy to service with its belt drive system and completely tool-less plastic panels that are removeable for access to critical components. The 858 engine was built to complement the platform. The result: a snowmobile that can withstand the rigors of riding and minimize time off snow.
  • Arctic Cat took learnings from the time-tested 400 and 800 engines and created the incredibly durable and reliable 858 engine.
  • The engine has fewer parts and integrated mounting design in the crankcase — making it strong and easy to service.

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17 thoughts on “Arctic Cat Unveils 858cc Twin, High-Tech Gauge For 2025

  • Avatar for Rick S

    Put that motor in a modern motorcycle!

  • Avatar for Edward Abraham III

    I just hope arctic cat ditched the slot skirt piston design. What a way to weaken them pistons.

  • Avatar for Brandon

    That’s great… Sure be nice if Textron would give a big bore twin back to the ATV lineup. They’ve basically given up on the ATV line at this point.

  • Avatar for Viking

    This is exactly what I said on Aug. 30 right here. A 858 two stroke twin.

    Congratulations Arctic Cat. Looks like good design engine with good power likely 176-181 hp based on a 11% increase from the previous 160-165 hp 800.

    Polaris will now make the 9R (900) totally replace the 850 so both HP will be very close. Ski-Doo will also make the 850 a 900 and again similar HP all by 2025 model year. very nice to have 3 brands compete with each other (well 4 as Lynx is basically a Ski-Doo exact same motor).

    2025 Hay Days will be fun to watch the 850-900 grass drags with 4 brands competing.

    • Avatar for Derek

      I doubt the previous 800 made even 160hp 165 HP on the new machine sounds about right 176hp on a 3rd pull on the dyno run on the Patriot 850 consistently great motor.

  • Avatar for Ray Podvorec

    So just like the 600 introduce it and then we have to wait another year……fail fail fail!
    Why not wait until February to introduce 2025 models.
    So stupid!

    • Avatar for Gord

      I agree with this guy 100%. Ya build a new engine with all the hype and then tell everyone you can only get it a year later…… that’s crazy!!! Better shape up AC and offer some new years sleds with the new engine!

    • Avatar for Ed

      Supply chain issues us why the 858 is not out for 2024.

  • Avatar for Viking

    Smart move to do it at the biggest sled event in the world and get all the free publicity, very frugal widest publicity with no other brands competing with the great announcement. It was totally Arctic Cats moment.

    Actually they get a nice jump on snow check sneak peak interest which is good. Bad part is they give the competition a long heads up on what they have to do to match or better yet one up Arctic Cat.

    Nice gauges.

    Nice that the motor weighs less than a 600 so obviously they will redo but likely up size the 600 to a 700 based on the 858. This will likely have 156-161 HP.

    Obviously in Hay Days 2024 for model year 2025 or perhaps 2026. They will do two or three new motors.

    1. turbo 858

    2. 700 based (648) on the 858 so they will drop the 600.

    3. Four stroke Turbo (either the triple Yamaha) or twin Weber 850 (the Polaris FST 750 up sized).

    Polaris will be going 9R and 7R to replace the 850 and 650. I mean come on XCR 9R and XCR 7R sounds awesome, an obvious name that rhymes. Everybody knows this is going to happen.

    Will Cat beat them to the punch for the 700 which will be the meat of the market just like the 600s were and prior to that the 580s and prior to that the 500s.

    Congratulations to Cat. The Cat is back again. The Cat came back again.

  • Avatar for Viking

    The naturally aspirated 858 has way more power than what Ski-Doo did with the first 3-4 production runs of their turbo 850.

    The SD turbo limited build early release and then the first full year production and maybe the second year as well had only 165 HP i.e. no extra HP with the turbo, it just kept the 165 HP in all elevations. Later it was boosted to 180 then 185 HP.

    AC with no turbo has 176-181 HP and it likley is a lot lighter than the Turbo Doo so it may be faster as well or at least very close with no turbo lag and no weight penalty and no glowing turbo potential fire hazard.

    When the 858 gets a turbo it will likely have 10-20% more power so between 194-217 HP so more than the ThunderCat and Sidewinder. Aftermarket Tuners could/will make it 50% more HP so 264-272 HP again more than most tuned ThunderCats and Sidewinders and much lighter.

  • Avatar for Viking

    Great marketing move. All everyone will remember the only thing the media will write about for 22 and 23 Hay Days is Arctic Cat’s new reviles of a new chassis and new big bore.

  • Avatar for Viking

    Very sad AC did not revel a two stroke triple big bore and baby triple as they would truly be the market leader.

    Very unlikely AC will be the first to reintroduce a two stroke triple. This opens the door for Polaris and Ski-Doo to do this and dominate the market with the most powerful, most dependable , smoothest running motor for sleds.

    • Avatar for Doug Lennie

      two stroke triple is useless except for lake riding (small torque numbers due to small cylinders)

  • Avatar for Viking

    AC 858 will now be Top of Mind for all sledheads and be the de-facto comparison to the current 850’s which are lowered powered a full 7 months before Snow Check Sneek Peek order deadline so great advance marketing move by AC.

  • Avatar for Viking

    Really sad AC did not go forward in 2003 with their ZRT 1100 with power values that produced 190 HP and instead made the 700 cc FireCat 700 with 140 HP as stated by Joey Hallstrom from AC. Watch the Carbide podcast 1 hour long interview with him.

    Imagine what that tripe triple would produce now. AC would be the Boss Cat with that motor (remember the Boss Cat how cool was that).

    Triples are way more reliable and as smooth running and best sound. Big twins can’t last long due to all the weight of those big pistons rocking in the jugs. Every 800 cc and up sled is doomed because of this basic mechanical fact. Not too mention way too hard to start with a recoil and too hard on a battery to move those massive pistons in cold weather, have to slowly pull it over manually before use the key to start it.

    Now 600- 700 twins do last long (easily 2-5 tomes as long as big bores) so lets hope AC sleeves down the 858 to a 658 or 698. Now we are talking a great long running durable motor. This should be announced at Hay Days 24 and released in 2026.

  • Avatar for Steve

    Its actually going to be model years 2026-27 by the time these 858’s are good to go. I wouldn’t by a first year engine from any brand. Look at the disaster Polaris had with their 850’s on year one with many of them blowing up or having bearings and electric systems fail prematurely. It will likely take a year or two for Arctic Cat to iron out all the running kinks of the new 858. In other words time to correct all those compromises they made in design that they did not disclose to the public. Plus by the look of everything shoehorned into an even smaller footprint they look like a real pain to work on.

  • Avatar for gerald st jarre

    the other 3 brand of sled have a lot of work to do to catch up to YAMAHA 998 CC,, as proven ??


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