From Mountainhorse:
"Here is what I understand so far... more photos and details coming this week.
The 800 in both the rush and the RMK are a common rail, 2 injector SDI system running 4-bar (58 psi) fuel pressure.
The FPR has been moved from the Pump Flange Assy (PFA) inside the tank....and been replaced with 2 rail-mounted FPR's to help stabilize any pressure fluctuation and provide a more precise fuel metering function.
The cylinders are ported differently, but it uses the same cylinder head/pistons as the 2010 800 CFi-4's.
The throttle bodies are mounted at a slightly different angle, tilted up with new TB boots to clear the new bulkhead and mate with the new airbox.
This engine sits lower in the bulkhead than the previous IQ fabricated assembly... lower center of gravity.
The engine mounts in the same way as the Rush 600 small block motor. (see dwg below)
The Oil pump is similar to the current design except that it is rod-linkage connected to the throttle body for more positive control and sync to the engines needs.
The crankshaft is the same as the 2010 M.Y. and retains the large PTO bearing, pressure fed by the oil pump. The PTO taper remains the same at 32mm.
A new torque mount has been incorporated to locate the engine more accurately under load and keep it aligned.
Two ring pistons have been retained, and compression has been bumped just a tad.... Polaris has been at work on this motor and new injection system for a while now.
This new Bosch fuel system is new from the ground up and incorporates the TPS, temp and DET inputs you are already familiar with.
Exhaust valves remain solenoid activated, controlled by the ECU like current CFi offerings.
The MFD (Gauge) and digital wrench now access the info in the ECU via a CAN-Bus net.
In the demo that I did in Mt last month... the power delivery was spot on and Noticeably more responsive with better top end than the current 2010 MY sleds we had to compare them to as well as personal experience on this chassis.
The motor will be 2012 compliant and is pending final calibration/Validation of the current map... which to my understanding already meets the 2012 standards.
There are NO HP numbers avail from Polaris on this engine.. nor do I believe (IMO)... that ANY #'s will be available until independent dyno testing is done next season on consumer-delivered models.
Hope this helps. :i_need_snow:"
