Ram 3500 DRW 6.4L Hemi "Game Changer"

ib516 wrote:

wintersun wrote:
People always seem to assume that with a heavy truck the 3.73 gears are going to provide better fuel economy than 4.10 gears in real world use when there is no reason to believe this is true. The higher gears make a difference with the EPA test that is done indoors with the truck not moving and this helps the fleet mileage overall. This is not the same as dealing with gravity and air drag and tire scrubbing in the real world.

I got 17 MPG on average with a 1998 Tahoe SUV with the largest V-8 sold at the time and that was with 4.10 gears and a 4-speed automatic transmission where 4th was a 1:1 gear with no overdrive. Now we have 6 and 8 speed transmissions that have 2 or more overdrive gears to compensate for the lower gears in the differentials.

The Ram gas engine like the new engines from GM have the very old approach (used in the 1980's with the Cadillac) of shutting off gas to some of the cylinders. Trucks benefit from lighter weight and more gears and in some cases with better motor oil that is a lighter "weight" to gain fuel economy. Even so this is a trivial gain in terms of the total cost of ownership.

The B Class Roadtreker motorhomes with their Mercedes 5-cylinder diesel engines get 25 to 28 MPG in actual use with them fully loaded and passengers on board. That is more than double the fuel economy of the Ram with the camper.

All GM 4 speed autos in 1998 were 1:1 in 3rd and 4th was overdrive (0.69:1). It would have been a 4L60E trans in that Tahoe BTW.

25-28 mpg? Really? Most reports I read say 16-21 mpg....
What kind of hp/tq does the Mercedes 5 cyl have? More than or equal to 410hp/429tq? If not, then it is likely it can get better mpg, but it has less power. Depends what you want.

A Prius with a tent in the cargo hatch would get ever better mpg than a Mercedes class B MH, but it too has less power.