Speedwerx ECU Tunes // 2025-2026 Arctic Cat ZR / RIOT / M 858 C-TEC2 Catalyst

ECU Re-Mapping for Arctic Cat 858 C-TEC2 Models 

Our ECU programs offer the most control to all of the hidden features in the stock ECU and allows us to produce the most power with the best throttle response and acceleration. 

Currently Available Tunes -

Stage 2 - 0-5000' - with Pipe/Y-Pipe/Head/Intake - 91 Octane Non-Oxy

Stage 2 - 5000'+ - with Pipe/Y-Pipe/Head/Intake - 91 Octane Non-Oxy

500' Drag Race - Stock Machine - 91 Octane Non-Oxy - +10hp (not for trail use)

More ECU Tunes are in the werx- stay tuned for more information and a release date!

You must send your ECU to us for re-mapping! Please include a note with your return address and order number. The return shipping cost for the service of your choice will be added when purchasing online.

Ship to:

Speedwerx, Inc.
20195 Greystone Avenue
Forest Lake, MN 55025

 

About ECU Tuning:

Throughout our extensive R & D experience, we found that recalibrating the ECU/ECM is the best way to get the most out of your machine. We do this by taking the time to go through the entire ECU and optimize it from the ground up. Something that was not commonly done in current ECU tuners. This way we can tune it to as close to perfection for every scenario to outperform your current programming configuration. Your machine will be tuned and perform just as well as a machine that was on the dyno and tested for months on end so that it excels in every situation to be smoother, faster, more efficient, and more reliable.

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 

 

Sending us your ECU is always the easiest and preferred way to get it done, but for those that wish to purchase a tool to flash their own ECU, we are using the new industry leading EZ LYNK Auto Agent 3 system. This will not only allow you to flash your ECU but you can also do much more.

• Data Log live and record data to share with tuners or friends.
• Run diagnostics checks on your machine as well as several other powersports and over the road vehicles. (brand-specific cables required for other powersports machines)
• Reset power valves on Polaris 850 and 9r models.
• Flash your own ECU with optional ECU Flash Power-Up Adapter

 

Link to Instructions: How to Flash with your Auto Agent 3 Device

 

Get Connected with The World's Most Powerful Vehicle Scan Tool. EZ LYNK puts your technician in the front seat whenever and wherever you choose and is the vehicle interface for all EZ LYNK apps.

The EZ LYNK Auto Agent 3 Vehicle Diagnostic Scan Tool and Electronic Logging Device (ELD)

Who is it for?

Vehicle Owners - From 18 Wheelers to Powersports and everything in between. See what we offer for your Vehicle

Vehicle Technicians - Get Connected with your customer and their vehicles; Whenever and Wherever

Transport Companies - Owner Operator, Small and Large Fleet Sizes and even Bus Transport Companies

Commercial Motor Vehicle Drivers - Hotshot, Short Haul, Long Haul, Agricultural and Construction

 

60 Second Setup:

Plug the device into the Vehicle's OBDII Diagnostic Connector

Install the EZ LYNK Mobile App on your Android or iOS Device

Connect via WiFi

Diagnostic Scan Tool and More:

 

A Connected OBD Scan Tool for You and your Vehicle's Technician

Lynk with your Technician

View and Record Vehicle Data Parameters in Real Time

Share Recorded Data Logs with your Technician

Read and Clear Diagnostic Trouble Codes (DTC)

Perform Technician Recommended Vehicle Functions

Install Vehicle Firmware Updates provided by your Technician, Over-the-Air

Chat with your connected Technician, within the Auto Agent Mobile App

 

Auto Agent 3 w/ OBDII Connection

Devices and Software Compatibility:

Android 8.0 or Later

iOS 12.0 or Later

iPad

iPhone

iPod touch

 

Additional Accessories to expand the Auto Agent 3 Connection and Convenience:

Class 8, Medium and Heavy Duty (Semi) vehicles - Auto Agent 3 HD Cables (6 and 9 Pin Round)

ATV, UTV, SnowMobile and WaterCraft applications - Auto Agent 3 Powersports Diagnostic Cables and ECU Flash Power-Up Adapters

EZ LYNK Phone Window or Dash Mount - The phone mount that sticks!

EZ LYNK ELD system requires a monthly subscription