Are large gas motor Rv's underpower?
At the risk of getting someone angry for me asking the same question they don't want to see again, that no doubt some people feel has been discussed enough. Are gas Class A's underpowered to tow a...
Forum Discussion
Daveinet wrote:DanTheRVMan wrote:I'm not sure I agree with this statement, because it makes an assumption about RPM. All the torque in a world is nothing without RPM. Back in the day, I could leg press over 1000 lbs, but give me a bicycle pedals and hook me up to your drive shaft, and I'm not going to accelerate your 30K lbs motorhome. Leg pressing 1000 lbs was very slow, so I would be limited by RPM. Since the RPM is limited, there would be no RPM room for torque multiplication to increase the torque to the drive wheels.
How fast you accelerate to that max velocity up hill is a function of torque and weight.
Basically it comes down to the fact that one can not quantify any performance without both torque and RPM. Torque alone does not quantify the actual output. That is why the quantification of HP exists as it quantifies total output.
I probably should have said torque at the wheel, but from a practical view point you can get an isb and isl engine with an allison 3000 transmission which means they have similar gearing depending on other variations in the drive line. The higher torque will get it accelerating quicker which is all Mr. Mark really wants to know.
If you want to accelerate thru several gears you keep shifting back down to low rpm at each shift point and that is where low end engine torque helps.
Everybody is going to go up the hill and most of the time maintaining speed not accelerating.
Most DP benefits IMO are about air ride, exhaust brake, fueling in easy to maneuver truck lanes, and quieter ride. Not the power that is constantly debated. Most MHs out west are gas that go up every mountain just like the DP.
