More info on Ford’s updated Super Duty powertrains
Back in February we outlined the broad strokes of the new gas big-block V-8 and in-house-designed Power Stroke turbodiesel V-8 that will power Ford’s heavy duty and commercial trucks for 2020. Now we have lots more details to fill in.
As a reminder, the new 7.3-liter gasser slims down enough to fit in all of Ford’s motorhome and cube-van chassis-cab applications by ditching two overhead cams in favor of a single cam snuggled deep in the block—a technology that’s been absent from Ford’s Super Duty truck lineup since the overhead-cam “Modular” engines replaced the “385” family of pushrod big blocks in 1997. (Note—it does not easily fit in any Ford cars.) And it mounts to a beefier new 10-speed transmission with new features.
Best in Class Gas-Engine Power/Torque
As an option in its 2020 F-250 and F-350 trucks, Ford’s new 7.3-liter V-8—that’s the largest displacement in the class—will crank out 430 hp at 5,500 rpm and 475 lb-ft at 4,000 rpm. That shades GM’s 6.6-liter V-8 by 29 hp and 11 lb-ft and Ram’s 6.4-liter Hemi by 20 hp and 46 lb-ft. Note that the 7.3 replaces the 288-hp/424-lb-ft 6.8-liter V-10, while Ford’s SOHC 6.2-liter V-8 still serves as the base engine in the F-250 and F-350, producing 385 hp at 5,750 rpm and 430 lb-ft of torque at 3,800 rpm. The 7.3-liter will be standard on the 2021 F-550, F-600, F-650 and F-750 Medium Duty trucks and E-Series, as well as F-53 and F-59 stripped chassis, and in many of these applications rated at 8,500-plus pounds (3,855 kg) gross vehicle weight, engines are rated for continuous power and the useful rev range is much lower. In most of these applications, the engine is rated at 468 lb-ft at 3,900 rpm, with horsepower limited across the rev range to the 350 hp it makes at the torque peak.
Built to Last Indefinitely
The 7.3-liter’s forged steel crankshaft features oversized main and rod bearings, and it’s fixed to the block with four vertical and two horizontal cross bolts. Many of the materials in use are upgraded to turbo-engine specifications. The roller bearings on the valve tappets are carbon-nitrided, piston-cooling oil jets are employed, the valvetrain is fed much higher rates of oil flow, and the variable-displacement oil pump is designed to be able to increase oil flow to maintain pressure as bearings wear or when viscosity drops at very high temperatures. The wear evident on an engine dismantled for our viewing after 3,200 hours of max-output running (that’s 133 days of 24/7 flogging) is apparently so minimal that it’s difficult to extrapolate a projected failure mileage.
Power Stroke Diesel Gets Steel Pistons
These new one-piece forged steel pistons are far shorter in height than the second-gen Power Stroke’s aluminum pistons, and they drop the compression ratio from 16.2:1 to 15.8:1. They feature much tighter ring lands and what are claimed to be the lowest-tension rings in the industry (for lowest-in-class friction). The piston pins are smaller than usual, and the connecting rod bearings they run in feature bronze inserts. The mass of the new steel pistons is only slightly greater than the aluminum ones they replace. New split-stream oil-cooling jets target both the piston crown and those new smaller piston pins.
10-Speed TorqShift Transmission
Almost all 7.3-liter and Power Stroke commercial applications will use the new 10-speed transmission, the exceptions being the medium duty (F-650/750), stripped chassis (F-53/59), and E-Series (E-350/450) chassis applications, which stick with a heavy-duty six-speed. As we noted in February, these Super Duty applications use the largest of three size offerings, and now we can note that it’s roughly 25 percent longer and 17 percent bigger around. It features a new-spec automatic transmission fluid validated for a 150,000-mile (241,402-km) change interval. The ratios differ very little from those in the F-150 and include three overdrive gears. On commercial vehicles, there’s a fuel-saving feature that selects neutral any time the vehicle is at a stop with the brake applied (think of it as auto-stop/start for transmissions). Gas and diesel fitments differ slightly, with the diesel getting a reinforced torque converter, an extra clutch element in two gears, and a fourth planet gear on the output carrier.
New Tranny Drive Modes
The outgoing six-speed only offered normal and tow/haul. This one adds Slippery, Eco, and Deep Snow/Sand. Slippery upshifts earlier to limit wheelspin, while Deep Snow/Sand allows wheelspin and provides a more aggressive throttle calibration. Tow/Haul mode slows shifts down a bit to ensure appropriate torque is on tap in the next gear. Tremor off-road truck models will also get an off-road mode.
Most Powerful Power Takeoff (PTO)
Offered as standard equipment on 6.7-liter commercial chassis-cab vehicles (and optional on 7.3-liter), the new PTO delivers a best-in-class 300 lb-ft of torque in stationary mode. Ford claims that’s 20 percent (or 50 lb-ft) better than the nearest competitor. The transmission case is strengthened and features a 10-bolt PTO attachment. If that’s still not enough torque, opt for the “split shaft” PTO that packages between the transmission and the driveshaft so as to deliver the engine’s full power and torque to your equipment.