polaris 550 engine fish hook chart
Amsnow
ExcursionPSD:
I have been told that some of the features of the improved 550 fan are:
* No-Offset Piston to improve durability
* 3D Digital CD Ignition
* Improved Combustion Chamber Design
* Improved Exhaust System
* 1mm thicker piston ring land
What does 362% more STABLE mean?
Also, how can it have a 3D Digital CD Ignition without a Throttle Position Sensor (TPS) or Temperature Sensor?
Polaris_Industries:
You are correct in regards to your laundry list of changes to the 550 engine for 2004. The measurement of improved stability is derived from a fish hook chart which details the performance attributes of the "old" 550 fan engine to the improved version found in the 2004 model year lineup. In short, the new engine is dramatically more stable, produces a very broad and flat powerband in comparison, and continues to deliver great performance when conditions change (i.e. temperatures change and or jetting is not ideal for conditions).
The 550 utilizes a digital ignition, but not a 3D timing map, thus the reason for no TPS sensors.