Speedwerx Stock Muffler Mod // Polaris 850 Patriot Boost VR1 / Assault / RMK

We designed this Stock Muffler Mod to cope with the rules and regulations many of us are facing on the trail. This modification to the stock muffler increases the flow for the higher horsepower tunes, but keeps a stock external appearance with little change in the sound level. There is a very small gain on the stock tune but we are not really interested in that- performance tunes require a more freer flowing muffler and until now, all of those mufflers came with increased sound levels and a risk of fines in certain regions of the world. This muffler modification produces almost identical power numbers to our Standard Lightweight muffler or L2 Series muffler with our Stage 2 and 2.5 ECU tunes. The cost of the modification service is $189.95, or a modified muffler can be purchased outright for $1039.94 (OEM muffler is $849.99). We try to keep modified cores in stock and available for exchange to minimize the turn around time (subject to availability and demand). 

The base price is for the modification only- you must send us your stock muffler for exchange or modification before we will ship your order! Please include a copy of your invoice or 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 Ave N
• Forest Lake, MN 55025

Update Feb 2024: Speedwerx Tunes and Mufflers Tested at DynoTech Research!

Boost VR1 Low Elevation Calibration Dyno Test

• Stock Tune:  185.2 hp with Stock Muffler Mod
• Stage 2 - 91 Non-Oxy Pump Gas ECU Tune:  200.1 hpwith Stock Muffler Mod / 200.0 hp with Std Lightweight Muffler
• Stage 2.5 - 91 Non-Oxy Pump Gas ECU Tune:  210.6 hp with Stock Muffler Mod / 212.4 hp with Std Lightweight Muffler / 213.6 hp with L2 Muffler
  

Stock, Stage 2, Stage 2.5, and Stage 4 Tunes with Stock Muffler Mod (Black 25/Aqua 27/Pink 29) vs. Lightweight Muffler (Lt Green 39/Purple 37/Lt Blue 35) vs. L2 Muffler (Green 11/Dk Blue 13/Red 17)

Stock Muffler Mod with Stock, Stage 2, and Stage 2.5 Tunes

This modification to the stock muffler increases the flow for the higher horsepower tunes, but keeps a stock external appearance with little change in the sound level.