Heavy half pickup

mileshuff wrote:

jus2shy wrote:
To move any load at any speed, it's all horsepower

Diesels are preferred because of their very high low end torque. They've never been horsepower monsters. Nor have the ever been acceleration kings. A Dodge Viper with V10 has far more HP than any of the big 3's 3/4-1 ton trucks. Care to put a trailer behind a Viper and see how the engine performs? 800ftlb vs 450ftlb is a huge difference.

Dodge was smart in dumping the V10 gasser from their 3/4 and 1 ton trucks even though it performed equal or better than the diesel and cost less. You won't get 500,000 miles out of a gas engine very easily as you will with most diesels.

But my complaint about the Ford 6.2L is more about the cost. It is a $3500 addon but only available on the upper tier Ford 1/2 ton trucks already rather expensive. Why bother?

Right, diesels make lots of power down low because of torque. So at say 1,600 rpm, the diesel is already making around 200+ horsepower while a gasser at that rpm is probably in the 100 range. In the end, the diesel is producing way more horsepower at a far lower part of the RPM curve. It's just that people tend to give all credit to the torque rating when it's really the torque output at a given rpm (horsepower). I can also guarantee that the viper motor (if able to get at its max horsepower band) would out-pull a truck, but it wouldn't last very long doing it LOL.

Here's a good empirical example, say at 1,600 rpm to keep things even:

Diesel:
horsepower = (RPM*Torque)/5252
(1,600*800)/5252 = 1,280,000/5252 = 243.72 horsepower

Ecoboost: (for the ecoboost, I'm estimating that it makes 350lbft at 1600 given the graph I posted earlier)
horsepower = (RPM*Torque)/5252
(1,600*350)/5252 = 560,000/5252 = 106.6 horsepower

(some edits below)

Doing a little reverse work, the ecoboost would have to hit 3,050rpm at full-torque to match the work being produced by the diesel:
(3,050*420)/5252 = 1,281,000/5252 = 243.9 horsepower

And doing some interpolating, the 6.2L motor from ford would have to hit about 3,600rpm where it's putting down 360 lb-ft of torque before it matches that power output:
(3,600*360)/5252 = 1,296,000/5252 = 246.76 horsepower

(end edits... yeah call me a numbers geek)

So for a given RPM, the diesel is pulling hard at 1,600rpm because of how much horsepower it's producing at such a low RPM. It is that big torque that allows the diesel to produce so much horsepower at a very low RPM. So in the end, it is horsepower production that gets your load moving, it's just that diesels do it so low in the power band that it comes on early. But the advantage of gassers is that they have far more RPM capability, so they produce their horsepower far higher in the rpm band than the diesels. Which is why they need so much more gearing and tend to be more inefficient. But in the end, the gassers can match the horsepower of a diesel, they are typically more strung out doing it though. Modern gas motors are made to scream all day long though compared to the motors of yore and this doesn't hurt them all that much to be screaming. It's just that they're very inefficient at that point.