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Old 10-30-2003, 08:21 PM
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5.4L 3 valve vs Hemi - yet again

OK, first I'll admit I'm new to the forum but I've read a high percentage of the recent posts. I've contemplated becoming a member for awhile now. . . , it's the whole Hemi comparison that finally pushed me over the edge.

I'm not sure why Ford decided to pick on the Hemi during it's recent barrage of F150 commercials, but I think it's going to backfire. Whenever Ford talks about superior low end torque it adds the disclaimer of 1,000 rpm in fine print as if that is the only engine speed it can "measure up". Problem is, how do you use that "superior" torque at 1000 rpm? If you go WOT with your automatic trannies from idle you can surpass 1000 rpm before you even move thanks to the stall speed of the convertor.

The whole 80% torque from 1000 up sounds good but apparently isn't unique to the Ford 5.4L. Local dyno put a manual trans heavy duty Ram on the rolls and found 80% or better torque from 1000 up as well (and that's 80% of a higher number if you believe the 365 & 375 ft lb ratings Ford & Dodge have published at the engine).

This board does give credit to the Hemi winning a race if both trucks are unloaded, I agree. But if weight is added to both the Ford somehow will win?, I don't agree (read on).

Acceleration is a function of vehicle mass and force at the tire patch. This force is a function of torque at the wheel and tire radius. The torque at the wheel is a function of engine torque and gear multiplication from the transmission and differential. If you don't follow this logic, just understand that if two trucks weigh the same, have the same gearing, same tire size, and same driveline efficiency, the truck that makes the most torque at the engine over the course of a race wins. More engine torque will mean not only faster acceleration but superior pulling capability.

I contend that the Hemi has more torque at all speeds (except perhaps 1000 rpm although I'd like to see comparative graphs) and will therfore out accelerate and outpull the 5.4L 3 valve in equally equipped trucks whether it be unloaded or equally loaded.

I recall one member putting up a $100 bet to Hemi owners. I'd like to take that bet, and you can decide how the race will be run (0-60, 1/4 mile, loaded or unloaded). Any takers in Michigan?, there aught to be a few in Dearborn. If there are no takers as I suspect, I'll even add a couple hundred pounds to give you a sporting chance. Yes, my truck will be stock (as must yours).

I know I'm going to get flamed, but these are the facts as I understand them. Please do not kick me out of this forum, I'd like to read and learn any and all counterpoints with the ability to respond.