Billet Head Kit / Patriot 9r-850-Boost
- Billet Head Kit for 2019 & up Patriot 850, 9R, and Patriot Boost Engines
- Increase cooling capacity for lower running temps which helps maintain peak power
- Low altitude kits gain 4-5 mid-range and peak horsepower
- High altitude kits gain 8-9 HP in the mid-range and 7-8 peak
- BMP tune is required when running in combination with our pipe
- We recommend running BPR9ES NGK plugs
- 91 Octane is required for 850 NA
- 100 Octane required for Patriot Boost
- head kit instructions
We offer two different dome configurations:
850-36.5cc is a 12.5:1 compression ratio that works great in the 6000-9000 ft range and bolts on 7-8 HP in the mid-range and 5-6 HP peak.
850-40.5cc is our lower 11.8:1 compression version for sea level to 6000 ft and gains 4-5 HP. The stock 12.1-12.2:1 compression ratio makes the motor's detonation sensor kick on very easily and won’t allow you to lean out the motor for extra power. By bolting on this version it allows you to lean out your machine with a fuel controller and pick up 5-6 safe horsepower. Some people have purchased this version simply to make it run cooler and less likely to set off the detonation sensor and put the sled in limp mode. This dome-design is different than others with a unique wider squish band and radius giving you great power and better reliability.
- High altitude 850 PN: 04-318-H
- Low altitude 850 PN: 04-318-L
- All elevation 9R PN: 04-318-9R