[mileageman]

I'm not sure it would be worth it for GM to invest the resources in designing or updating and appropriate diesel to match current and future emissions regulations. Probably an easy 2 year endeavour if not longer. They should definitely go 8 speed and try to improve aerodynamics to improve fuel economy. Other than that I don't know, maybe they can try the hybrid truck route again. If done well electric motors should (in theory) be a great fit for truck applications. In practice, who knows?

 

[mileageman]

Ram diesel sales would be lucky to be 2,000/mth, I'm not so sure about claims by Ram that
those sales will increase from the current 10% to 20% of total 1500 sales.

Sure Ford and GM could compete but let's take GM for a second:
- give the silverado 5.3 an 8-speed auto and you could see fuel economy jump to 25 mpg,
a brilliant result that would impact around 75-80% of GM's half ton truck buyers.

Similarly, Ford's new lightened '15 F150, set to go forth and do battle with 2.7 Ecoboost,
an engine guaranteed to shake up any notions of F Truck buyers considering a diesel.
I have a hunch that the new F 150 with 2.7 EB will be mighty close to Ram ED V6 in
all the right areas like fuel economy and yet worlds apart in others like performance.

I don't think you're going to see a small turbo'd gas engine come anywhere close to a small turbodiesel *at least* until low sulfur gas is standard in the United States. Lean burning can't be done very well with current gas setups and that is a major source of gain for diesels.

Even then throttle less gas engines still need a lot of improvement, and the low non boosted CR might only be able to be addressed by water or water/methanol injection. Still, people are wiling to load DEF into their diesels now as a second required fluid, I could see people also be willing to add water/methanol into turbo/gas engines as a second fluid.

I know that nobody is going to build one but I would love to see what a 3.0L-3.3L pushrod V6 single turbo water injected setup could do. Give it an 8 speed and dump the torque converter for an electric motor and make a mild hybrid out of it and you would have a (probably) epic fuel economy engine.