With all the talk of fuel efficiency the last several years, it boggles my mind why Ford and GM are set to introduce V8 diesels with torque ratings in the high 400 to low 500 lb-ft range for their half ton vehicles. These seem like they would be a good choice for the 3/4 ton trucks, but major overkill for a 1/2 ton. I would think something in the 2.3-2.5 liter, 225-250 lb-ft range would be great for a fuel efficient truck. At least have it as an option. We already have truck motors that put out good torque, I don't see the demand for a 20-30% increase in torque for the 1/2 ton market. Shoot, my 01 Tundra puts out like 315 lb-ft, I think, which is fine.

Is it a return on investment thing? Wanting to put these new motors in the high trim level trucks to recoup their investment, and bolster profit? Or did the development of these motors start before the companies knew how bad the fuel price thing would get?  

In europe we have "small' diesels in our pick-ups, they are about 2.5 litres and put out respectable power, BUT! they are fuel efficient! my Mitsubushi L200 would give me 30 plus mpg, so why oh why are the big 3 still playing with huge diesel engines? Ford Gm both have great diesel engines over in europe , so why not just bring them over here?
watch out if VW bring their's over, my lady has a passat station wagon with a 1.9 litre diesel turbo and that gives us 50+mpg on runs!And beware if Peugeot ever decide to come over here, they have made great diesels for over 50 years!!!!!!!  

225-250 lb./ft. in a half ton would be laughably weak. I'm sorry. I'd make the benchmark at least 350 lb./ft. for a full-size truck diesel.

Besides, the projections on the new Duramax 4500 are around 18 city and 25-26 highway. I'd say that's a pretty good trade-off for 520 lb./ft. of torque, and better fuel economy than most mid-sized crossovers.  

The Dodge V6 has like 235 lb./ft of torque, which is just fine for a base truck. If they want to use diesel motors to improve mileage, a large 4 cylinder, or small 6 cylinder turbo diesel would perform just fine. Have a small diesel for a base motor, and an optional V8 diesel (along with the gas motors) for those who need/want it.

I think they are over doing the size and output of their new diesels, given these all have more torque that just about any gas motor in a half ton truck.  

I own a Dakota/Raider quad cab with the V6 and 3.92 gears and 235lb/ft is not just fine, it is weak.  Put a family in the cab and a trailer on and it becomes laughable.  

I'm not debating that a smaller diesel option isn't a bad idea. Like a V6 with 300-ish lb./ft. for those looking for a super-economical option. But there will be half-ton guys looking for the big torque that a diesel provides.  

double post, bah.  

briarhopper:
I own a Dakota/Raider quad cab with the V6 and 3.92 gears and 235lb/ft is not just fine, it is weak.  Put a family in the cab and a trailer on and it becomes laughable.

I am not suggesting that a small diesel should be the only choice, just an available option. I think it would compare well to a base 6 cylinder gas motor. If you need to tow/haul heavy loads, you would not be opting for a base motor anyway. I think a small diesel would be perfect for fleet customers, entry level buyers, and for people who like trucks but can't justify the fuel cost of a gas engine.  

I don't think its so much for the torque rating, as it is the longevity, efficiency and mileage.  Diesel motors are inherently stronger and more efficient than a gasoline engine.  Obviously, the drawback is the diesel cost option.  

But, if I was in the market for a half-ton, I'd take a seriously look at a half-ton oil burner.  This Cummins is my first diesel, and I can tell you, I'll never go back to a gas truck.  Ever.  

Just remember, these trucks start at around 5000 lbs and its torque that is required to gets this weight moving.
The 4.2L V6 coming from Cummins for Dodge has around 420 ft/lbs, thus the 4.4L (Ford) 470 ft/lbs, Duramax 4.5L around 520 ft/lbs and the new 5.0L from Cummins/Dodge (?).
However it should be in the neighorhood of 20+ mpg city and 25+ highway for these trucks. And rumored that Toyota has an agreement/purchase with Isuzu for some diesels . All of these as an option should be under $2000. Does 300,000 miles of reliablity at these economy numbers make sense, depends on how far you drive and what you pull.
Also consider these will now most likely become the first option on the 3/4 ton vehicles ... and options on some of the sedans ????
 How bout Caddi's 2.9L from Europe, a strong little performer in itself, in a Colorado ... too cool
a little more than my two cents
 but consider the new direct injection, V8 power from V6 motors  

I always get a kick out of these examples that are "laughable." It does not take much torque to pull most trailers with a stick shift tranny. That is, provided you don't care about pulling every trailer up steep grades at 80 mph.  

Look, if you want to be real literal about it, sure you could put a four-cylinder diesel in a full-size truck, and it would motivate it OK. Might even pull a decent-sized payload or trailer.

Heck, the Isuzu NPR and most other cab-over medium-duty trucks are four-cylinders. Granted, they're hosses for four-bangers, at between 4.6 and 5.2 liters, and they move just fine.

But viewed within the context of consumer expectations in the U.S. market, I don't think it's a viable option. I think the only thing that could really convince buyers if you could get it to breach the 30 highway MPG benchmark. Then, you might get some buyers.

But it's kind of the law of diminishing returns at that point. The amount of R&D that would be required to get a full-size truck to meet that benchmark would probably cost a lot more than to develop a V-8 or V-6 turbodiesel that got mid-20s highway MPG, which for most buyers, would be more than enough.

The other factor you need to consider is the difference in power delivery characteristics between gas engines & diesels. Even though diesels produce eye-popping torque figures, their dynamic operating range is much smaller than a gas engine, and much of the time, the big torque is to offset their relative lack of horsepower, and lower RPM capability.

For instance...On the 4.4L turbodiesel in development for the new F-150, preliminary figures are 300+ horsepower and 450+ lb./ft. of torque. Yet Ford is saying that acceleration will be equivalent to the 5.4L gas engine. You'd think with just as much horsepower as the gasser, and quite a bit more torque, it would be quite a bit quicker. But consider the redline on the diesel will probably be around 4,000 RPM, whereas the redline on the gasser is about 6,000 RPM, give-or-take.

Just a few things to take into consideration.