With any turbocharged application, turbo lag is always a concern. The turbo needs exhaust gasses to spool and provide charged air back in to the engine, and the engine needs the charged air to make power. This cycle can create a lag in response time from squeezing the throttle to actual power delivery. Unwilling to take the compromise, the team set out looking for a unique solution. Sure, there were some high-end electronic turbocharger assist technologies in automotive, but none that had the weight and cost requirements needed for the snow application. They needed a lightweight, simple solution.
The result is a reed valve intake mounted right in the plenum, about three inches away from the throttle bodies. When the engine accelerates from low RPM or idle, the reed valve allows fresh air directly into the plenum, just like a naturally aspirated engine. The exhaust is allowed to build up boost while the response of the engine doesn’t suffer. Once adequate boost is delivered to the plenum, the air inside becomes pressurized, naturally forcing the reed valve shut. The lack of electronics or controls allows the system to be near immediate, with no transition hiccups as the engine comes on and off boost.
“The reed valve in the intake was all about getting as close to naturally aspirated response as we could, while maintaining really good driveability. The simplicity of the reed valve accomplished both.” added Buchwitz.
The Patriot Boost is truly an engineering marvel, resulting from a no stone unturned approach to development. Purpose built for the immense demands of ultra-high performance snowmobile riders all within the EPA’s regulations, it delivers performance that is unrivaled. 10% more horsepower than an 850 at sea level, and a whopping 50% more power at 10,000 feet of elevation in a reliable, high quality package, all while running 91 octane right straight out of the pump. Anyone who has gotten the chance to ride one can attest – it works damn well.