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New Arctic Cat 858 Engine: Everything You Need to Know

Last year, at Hay Days 2022, Arctic Cat introduced the Catalyst chassis (read…). This year, the manufacturer is at it again by announcing the arrival of a new engine for its 2025 snowmobile lineup.

Arctic Cat has named this engine the 858. It will gradually replace the 800 C-TEC2 in the coming years. Although it shares the C-TEC2 technology of Arctic Cat’s 600cc and 800cc engines, the 858 is an entirely new engine specifically designed for the Catalyst platform.

Arctic Cat 858 Engine (top view or top of cylinders)
Arctic Cat 858 engine (View of crankshaft end)


  • Optimize mass centralization
  • Lower the snowmobile’s center of gravity
  • Reduce the weight of the snowmobile compared to the 800 C-TEC2 models
  • Provide a more powerful engine than the 800 C-TEC2
  • Enhance the reliability and durability of the powertrain

Choice of Displacement

When the manufacturer announced last year that it planned to replace its 800cc engine, it suggested that the new displacement would be greater than 850cc. Many thought the design team would offer a 900cc engine or even a 1000cc engine.

One Might Wonder: Why a (Mere) 858cc Engine?

The answer is quite simple. The larger the engine displacement, the heavier and bulkier it becomes. This ran counter to what Arctic Cat aimed for with its Catalyst platform.

Therefore, they opted for an engine with the same bore as the 800 C-TEC2 but with an 8% longer stroke. As a result, the new engine has a bore (cylinder diameter) of 85mm and a stroke (piston displacement) of 75.6mm for a total displacement of 858cc.

Arctic Cat 858 Engine

New Exhaust Control System

The new exhaust valve design is very intriguing. It allows the valve to remain extremely close to the piston as it moves. The exhaust flow is smoother over a wider RPM range, resulting in more consistent power and cleaner emissions.

Arctic Cat 858 Engine
Arctic Cat 858 engine – Exhaust valve displacement

The key element enabling this is the new push-pull actuator, which provides precise control of the exhaust valve position. Naturally, all of this is managed by the engine control module (ECM).

Arctic Cat 858 engine – Sketch showing the small clearance between valve and piston side

The new geometry of this system allows for a 250% greater adjustment. Additionally, the design reduces the number of components from 30 to 15 compared to the 800 C-TEC2 engine, while improving low-end torque and efficiency.

Arctic Cat 858 engine – New exhaust system

New Exhaust

Of course, Arctic Cat had to design a new exhaust system calibrated for the 858 engine and the Catalyst platform. It is lighter and equipped with robust anchors.

Air Intake System

Here too, the Arctic Cat team worked to make this system as simple as possible while aiming to minimize its weight and noise level. Additionally, this new design reduces the number of seals, minimizing the risk of leaks. Furthermore, engineers have incorporated a secondary air intake under the hood in case the external air intake becomes blocked by snow.

Arctic Cat 858 Engine
Arctic Cat 858 engine – Air intakes and ducts


Arctic Cat, like most manufacturers, does not disclose the power output of their engines. Nevertheless, they have informed us that the 858 is 11% more powerful than the 800 C-TEC2 while being 3% lighter than the 600 C-TEC2.

Additionally, if we consider that the power of the 800 C-TEC2 is 160 hp (as per information available online), the 858 should theoretically produce a little over 177 hp. C

onsequently, considering the reduction in the weight of the Catalyst chassis and the engine, the power-to-weight ratio of a Catalyst 858 snowmobile will be significantly better than that of a corresponding C-TEC2 model.


Arctic Cat 858 Engine

Significant Weight Reduction

In the end, the folks at Arctic Cat estimate that the Catalyst 858 snowmobile will be 10% lighter than its equivalent in the 800 C-Tec2 version. Knowing this, there’s no need to tell you how eager I am to try out an 858 at the next SnowShoot!

Continue reading our latest Arctic Cat articles:

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