what happens after the doo's max rpm rating? do the other sleds just bow down and say go doo? We can't rev anymore or it's not fair? Probably not. Skidoo has a great motor but it's not a powerhouse compared to the other two. Cat's 800 is damn close to either and I'd be hard pressed not to say it's as torque-y (bad grammar-it's late) as the 850 skidoo. I'm not knocking the 850 by any means, but I feel like you are missing the point here. Clutch for your motor's powerband. It might make more torque at a lower rpm but if both sleds are clutched right the polaris will just be running 300 rpm higher and they both will pull hard. I've spent time on all three and they are all fantastic.
What happens after the Doo's max RPM rating? Well it drops like any other motor does as I stated already and the graphs clearly show. If you go over 8000 or whatever you aren't clutched right. I didn't know there was a point to get? I was just laying down the truth behind the graphs which are, yes strictly crank, I think you missed the point. I wasn't ever talking about clutching. Read below.
So what I think you should do next is post up the torque curves. Then I want to see your sled pull itself around at 5000 rpm where the torque is greatest... More torque in a high strung 8000 rpm 2 stroke is mostly worthless. Clutching and gearing can easily compensate for the few extra lb/ft you think you have.
I agree, Doo made a pretty good motor this time around. Is it head and shoulders above the rest? Not from my experience, not even close.
I thought about it, you could take the points on this graph and calculate the torque curves but I have already seen them on bikeman's graphs which are similar. I don't know what you are agreeing with in reference to what I said. Yes, the Doo 850 is a good motor, no I never said it was head and shoulders above the rest. People seemed to be misinterpreting the graph and thinking that the Doo makes more power throughout its curve and it really doesn't with respect to time. Put the Poo up 300 RPM and boom you have the same power butttttt if you pick an RPM to observe the respective HPs at thennnn Doo makes more power at that RPM and therefore makes more torque (since it is generating more power at a lower RPM) that's all I was saying. Am I sounding like a broken record?
The CVT (properly tuned) does cater to the power produced, but the bottom line is they all have to run from engagement to peak RPM. The more power made from engagement to peak can shorten that time and allow a quicker acceleration. A electric motor would be a extreme example of this...peak power from 0-whatever RPM. Think a peaky 440 spinning a big track vs a 800 making similar peak HP. In my experience on a mountain sled, it's all about making as much power as early as possible which also makes clutching more forgiving.
Then factor in the clutches/calibration and how they grip the belt at various ratios will also effect how ANY power is transferred. Maybe the Poo clutches do a better job than the Doo and show more power to the track at lower ratios? I have not seen much track dyno data to say. These graphs are just one factor between crank and snow.
The bold statement is the way to start the conversation about clutching and drive system.
If you got on a sled with a motor inside and no drive system you would not be able to say "oh this motor is so much power potent than that other motor" you would have no way to feel that.
It is what is between the motor and the snow that enables you to gauge how the motor feels.
Motor > Clutching > Gearing Setup > Driveshaft Design > Track Design > Snow Conditions
Look at all the stuff between Motor and Snow before you feel anything. Or like shockman said we could discuss what happens before the motor (how it gets its power) Intake > Fuel Injection Method > Combustion Design > Exhaust > Motor
