- Joined
- Apr 7, 2014
- Posts
- 1,176
- Reaction score
- 605
- Ram Year
- 2015
- Engine
- Hemi 6.4
All it means is that:
1) Pushrod engines are cheaper to make
2) Fuel economy doesn't matter on super duties (3/4+ trucks in general), as they don't even have to report what it is and it in no way affects their fleet fuel economy.
The F150 though does, and AFAIK, The F150 isn't getting this engine, and its two most powerful engine options are turbos. That's more telling IMO when high power + fuel economy is needed.
Of course pushrod engines are cheaper to make. But engineering a new production motor in todays world is not. Fuel economy does matter regardless of whether or not they are required to publish figures. Ford engineers stated as much in a recent interview:
"We built a map of where an engine, can run stoichiometric air-fuel without a bunch of spark retard," Beltramo said. "That led us to a torque-per-liter value and a power-per-liter value, [which] knowing that, boxed us to 7.3 liters."
To come with up with a solution for a vehicle over 14,000-lbs, the 7.3-liter was generated to work at relatively low RPMs for fuel efficiency. It made sense with the creation of a pushrod two-valve, according to Beltramo. The Coyote 5.0-liter with an overhead-cam that powers the Mustang works best in the middle to top rev range, but something like that doesn't make sense when hauling and towing big things, this is where an engine needs to work its best in the lower RPM range to conserve fuel.
"If you used [the 7.3-liter] in an F-150 or something, it would not return the kind of fuel economy at light load as some of our other engine offerings that we deploy in that vehicle," Beltramo said. "There would be a hit for the displacement. But when you start talking about running day-in-day-out, at high weights...the displacement brings a big fuel-economy benefit."