Pro 800 RMX +5hp

Facebook Link

RMX Kits

Welcome to the state-of-the-art in high altitude setup, RMX Kits from Rocky Mountain Xtreme. Our RMX kits are developed for anyone who rides in Colorado's high elevations. These kits are not about ultimate horsepower or the ultimate highmark - they're about great driveability, superior fuel economy, and reliability.

Polaris 800 RMK Pro: RMX kits are available for the 2011-2015 Polaris Pro 800s. The most cost-effective combination on a Pro 800 is an RMX high compression head, coated pipe, and HPS can. That combination makes an extra 5 horsepower (at altitude) and loses almost 10 pounds of weight. On both chaincase and Quickdrive models, we also recommend installing new gears with a lower ratio (we carry geardown kits for new Pros from both Kurt's Polaris and TKI). While it is possible to make more power, the DET control system is very aggressive which necessitates using some combination of a fuel control box, better fuel, and timing control modules. Generally, we haven't found the price/performance ratio of those modifications to make sense for most riders.

Kits are currently available for:

Year Manuf Models Kit Type Horsepower Gain
2011-2015 Polaris Pro 800 RMK RMX + 5hp
2012-2015 Polaris Pro 600 RMK RMX + 3hp
2008-2010 Polaris 800 RMK RMX + 12hp
2008-2010 Polaris 800 RMK Stage 1 + 15hp
2007-2010 Polaris 700 RMK RMX + 4hp
2005-2006 Polaris 900 RMK RMX + 10hp
2006-2011 Polaris 600 RMK RMX + 9hp
2002-2005 Polaris 700 RMK & 800 RMK RMX + 5hp
2002-2005 Polaris 800 RMK Stage 1 + 10hp
2002-2005 Polaris 800 RMK Stage 3 + 13hp
2002-2005 Polaris 800 RMK Stage 5 + 19hp
1997-2001 Polaris 600 RMK, 700 RMK & 800 RMK RMX + 6hp
2007-2010 Ski-Doo Summit 800R RMX + 7hp
2003-2006 Ski-Doo Summit 800HO RMX + 5hp
2001-2002 Ski-Doo Summit 800 RMX + 5hp
2007-2010 Arctic Cat M1000 RMX + 14 hp
2007-2009 Arctic Cat M8 RMX + 10 hp
2005-2006 Arctic Cat M7 RMX + 6 hp


The Problem: Snowmobile engines, like most powerplants, are developed to perform well at sea-level. Unfortunately, we don’t have the luxury of that much air at 10,000 feet and actually are suffering from a 30-35% loss of horsepower. While the top end horsepower loss is bad, the loss of throttle response is even worse. Our super-responsive and very torquey twins simply don’t deliver their full potential at altitude.

The Solution: First, at altitude, nothing beats compression. The basis of any RMX kit is a modified high compression head. From there, we add a combination of pipe modifications, timing changes, canisters, fuel injection controllers, etc. that delivers the best bang for your buck. The kits are always designed to recapture throttle response and provide much better bottom end with more horsepower on top. The head change provides the basis for throttle response while the other components generally increase top end horsepower. Generally, we also strive to have a much broader power curve at peak RPM, which making the clutching more forgiving and means the engine will run well in a variety of conditions.

The Benefits:

  • Great throttle response: Nothing beats compression for throttle response
  • Crisper running: Compression cures any lean sports in the carburetion or fuel injection calibration
  • Better Mileage: Crisper throttle response means less time spent burning excess gas
  • More top end: More power means more speed
  • Easier to Ride: The powerband is much broader, which makes it much easier to moderate the throttle in deep snow and tight situations to avoid trenching.

Who are they for? RMX kits are designed to be our most user friendly performance enhancing options. Essentially, anyone who owns a snowmobile will like and benefit from the performance of these kits. The intent of these kits was never to build peaky, pipey, high RPM sleds, but rather ultra-responsive, easier to ride, and more fuel efficient snowmobiles.

What are the drawbacks? The kit was developed to be used above 8000 feet. Also, the increased compression and performance that the kits provide generally require the use of either non-ethanol premium 91 octane fuel or a mix of race gas and premium 91 octane ethanol fuel.

Price: RMX kits vary from $500 - $1100 installed depending on the model. If you're interested in buying a kit without having it installed, please call or e-mail for more information.

600 RMX