[quote=wwgkd]Including his beloved RX-8. :D[/quote]Oh yeah. Forgot he had one. Great point! :)
[quote=wwgkd]I think he means how flat you require it. For instance there are some torque monsters out there that use very old technology, though a graph of their power curve doesn't show it as flat as some engines using more modern techniques are achieving.[/quote] I would say that the importance of how flat the torque curve actually is, is definitely dependant on the actual amount of torque. If an engine is capable of pumping out 600lbs/ft of torque then it can swing up and down say 100lbs/ft or more and it wouldn't be overly noticeable. However if the engine can only put out 100lbs/ft of torque...
[quote=wwgkd]Not necessarily. Some relatively small engines achive quite high levels of torque at low RPMs, but they sacrifice peak horsepower. Also, the ability to run at low RPMs can lead to the same fuel effeciency as the higher revving engines despite a difference in displacement. These days people are too addicted to using the displacement size to judge mileage. Often widely varied engines achieve similar effeciency when made to do the same work. And a high revving engine is pretty much always a bad idea when heavy towing or most kinds of fourwheeling (a major exception being baja style racing) is involved for numerous reasons beyond NVH. Cooling, fuel consumption and wear and tear on parts, among other things.[/quote] Ah but what if the comparable engine was designed for extended high RPM use? IMO 3 litres is getting big. I don't know what car/truck you use for towing and off-roading but I can imagine that it has an engine that would dwarf a 3L one. Also instead of high revs a smaller engine with forced induction could be used to make the same power at the same low revs. It would most likely be more expensive than the simpler larger engine though.