Originally Posted by dhdad
When it comes to towing torque is more important than HP, especially low end torque and you can't beat a diesel.
This isn't entirely true. Horse Power is purely a calculated value based upon rpm and torque.
HP = (rpm * T) / 5252
While we can all agree that torque off idle is great for towing, once you're moving HP plays a larger role. Your RPMs for a given speed are determined by gear ratio. The rpm range on a diesel engine "usually" isn't as broad as that of a comparable gas engine.
Even an almighty diesel truck has to downshift to keep in the proper power band when the downshift wouldn't put it above its maximum rpm range.
My '06 Cummins was bad about this. I had a 6" lift, 37s, and stock 3.73s in it. It turned around 1600 rpm at 70 mph where stock was around 2100 for the same speed. Stock, it would chug up hills towing with no problems, but lifted it would downshift and turn about 3K RPMs. Why? Because it was programmed to do so.
Running an engine within its allowable rpm range is perfectly acceptable. Those of you scared to rev an engine for power must not own a boat. If you did, you'd be use to running your motor at mid to high rpm all the time. Mines got a 350 MAG and I run it at 4K rpm all day long and 5.2K often. If I stayed at 2K, I'd never get up on plane.