Tystevens wrote:
Perrysburg Dodgeboy wrote:
Buddylam that is what makes the Cummins the best diesel in a pick up period! The in-line six of my 5.9 even with the 48RE was turning under 1500 RPM in OD @ 65 MPH.
How is this different from the other diesels on the market, or even the EB, for that matter?
My Duramax would tow up just about any interstate grade out there at 65 mph, 1600 rpm, in 6th gear. My Ecoboost tows along on flat or slight inclines at about 1700 rpm at 65 in 6th gear also. It downshifts more often than the Duramax, obviously, but it takes an actual hill to make it do it, and spends probably 90% of its time on the freeway in top gear (I do live in Utah, so we don't have long stretches w/o some sort of hill). When the EB does downshift, it is usually to 5th gear and about 2200 rpm.
For what it's worth, I suspect the Ecodiesel would do about the same when towing w/in its ratings. That is one of the great things about these turbo-charged engines -- the low end torque is incredible.
Compare that to my naturally aspirated V8's. My 2010 Suburban pretty much spends its life above 2500 rpm with the trailer attached. It almost never reaches 6th gear, even on flat ground, and downshifts if someone sneezes! Not necessarily a knock against it, but it needs rpms to make its power.
More rpms = more parasitic drag and friction = more engine wear. Don't forget E=MC2 The engine parts load squares with increase in rpms. Side thrust from the connecting rods to the pistons, to the bore of the engine, etc.
At 57-58 mph trailering, in 8th gear, my Touareg is at 1490, maybe 1500 rpms (measured it today.) I'd have to double check. Both 7th and 8th gears are overdrive, direct lock up gears, no use of the torque convertor.
