Turbocharger Kit // 2025-2026 Arctic Cat M 858 C-TEC2

Speedwerx Turbo Kit // 2025-2026 Arctic Cat M 858 C-TEC2 

Our Turbo Kit comes complete and ready to install without any major chassis modifications. Comes with instructions and step by step video instructions will be available on our website and YouTube page as well. Kit utilizes stock coolant and oil lines to feed turbo. Fueling is controlled from a re-flashed ECU and standalone G3 controller box that controls the secondary fuel injectors. As of now we are the only aftermarket company running 4 injectors, but both Polaris and Ski-doo run them on their turbo sleds direct from the factory. This provides better throttle response, better acceleration, and better power. Our aluminum charge box comes pre-assembled with a high flow secondary air inlet valve to for improved throttle response and deep snow drivability. We also send a hood upgrade with the kit to remove most of the internal stock hood intake parts. Last but not least, we include our complete clutch kit with our adjustable weights pre-set to our baseline specs.  

This kit is designed to run on non-oxy 91 octane premium pump gas at all elevations and produces 215+ hp on pump gas at 8300-8500 rpm. The wastegate, secondary injectors, and our programming makes this fully altitude compensating from sea level to 8000'+. 

UPDATE 1/21/26: Fuel requirements-  6000’+ 94-95 Octane required.  We are running about 2 gallons of 110 leaded  or 2-3 gallons of 100LL per tank. 2500-6000’  98 octane required.  3.5 gallons 110 leaded. Or 6.5 gallons on 100 LL  Stock tank is about 9.5 gallons.   We are working on straight pump gas solution a this time.   We take this matter very seriously and we will have an update as soon as possible but there is lots of calibration and verification still required before this is complete. 

Key Features and Parts Included: 

• Super Efficient Xona Turbo with Low Intake / Charge Temps
• Tial Wastegate
• Stainless Steel Exhaust Components
• Altitude Compensating Secondary Injectors
• Secondary Injector Controller and Harness
• Dual MAP Sensors
• Aluminum Charge Box with High Flow Secondary Intake Valve and Piping
• Ecu Flash
• Oil Line Adapter
• Coolant Line Adapters
• Hood Intake Upgrade Kit with Bypass Valves for Improved Deep Snow Runability
• Complete Clutch Kit

TECH NOTE: Power Valve cables- we have seen a large number of sleds that the power valves are not set properly from the factory or they have moved, this dramatically effects the overall performance of you machine. Using AC tool # 836-00005 you need to confirm these are set right and if you have issues check them again. In our opinion, this is needed on every single 858 out there even in bone stock form. There is also a Technical Advisory regarding the Servomotor Bracket Alignment issued 12/5/25- your dealer may have already contacted you about this done this as part of the pre-delivery inspection, but they can help you with these adjustments if you are not comfortable doing them yourself. You can purchase the Adjustment Tool Kit here- https://speedwerx.com/apv-adjustment-tool-kit-858-c-tec2-models.html