I'm about half asleep but I've been contemplating a question (multi faceted) for those in the know about saw performance. Here goes-
We often make comparisons between saws and talk about rpms and chain speed for "high performance" saws. Somewhere in there the subject of torque or "stump pulling" power comes up.
There IS definitely a difference in lugging power between saws but are there any "rules" for determining a saw's 'torqueyness' short of actually running it? ( I know that some manufacturors publish torque output specs but I'm looking for general rules).
If 80cc saw A turns 13,500 rpm (no load) and perhaps 9000 rpm in the cut. And 80cc saw B has an "operating rpm" of 7000--- obviously saw A makes more Horsepower. What about lugging power? The "rules" I remember say that long stroke engines usually have greater low end torque than short stroke engines but Short strokes can rev higher and are usually more throttle responsive. Also, big heavy flywheels are harder to bog out that little light ones. Okay.
Suppose that Saws A and B have similar bore and stroke figures. Is the higher speed of A then purely a function of Port Timing? (Or rather mostly Port timing --I'm sure that crank and piston weights and flywheel weight all have some effects.) Will the slower saw be more torquey or is it simply a lower performer in all respects. If greater torque comes with lower peak rpm presumably we can change gearing with higher pin count sprockets and catch up some with the screamer but if performance is simply lower then a 50 cc 13,500 rpm saw will likely equal our 80cc slowpoke-Right?
Come on guys 'splain it all to me.
P.S. Everytime I contemplate RPMs above 12000 it simply amazes me!