Oil-Burning Rebel: First Drive of the 2020 Ram Rebel 3.0L EcoDiesel
Climbing a short, steep section of trail in the Iron Range Off-Highway Vehicle State Recreation Area just outside of Gilbert, Minnesota, was remarkably easy behind the wheel of the EcoDiesel-powered '20 Ram 1500 Rebel we were driving. With the low-end torque of the newest V-6 turbodiesel from VM Motori under the hood and the ZF 8HP75 eight-speed automatic transmission and an electric locker in the rear differential, the ascent was nothing more than a casual idle to the top. And we weren't even in low range.
The new third-gen EcoDiesel purrs like a kitten, with just the barest of an audible diesel heartbeat. Its 480 lb-ft of torque at 1,600 rpm outshines the Hemi 5.7L and bests its 1/2-ton diesel competitors. The new EcoDiesel doesn't disappoint—and it's available across all models and trim levels of the '20 Ram 1500.
New Building Block
Lift the hood and the new engine looks nearly identical to the previous turbocharged 3.0L EcoDiesel. But strip away the plastic coverings and underneath is a new compacted graphite iron (CGI) block topped with equally new aluminum heads. The new block weighs 15 pounds less than the CGI block of the previous generation.
The crankshaft and connecting rods are 4140 forged steel, and the redesigned aluminum alloy pistons have thinner rings along with a flat deck surrounding a newly designed fire bowl. The pistons also feature a connecting pin offset by 0.3 mm to reduce noise from piston slap. The quieter, smoother running of this EcoDiesel distinguishes it from the 2019-and-earlier models.
The new pistons don't need the valve recess in the tops like the previous-generation EcoDiesels because the aluminum heads have been redesigned with new ports and combustion chambers for better intake swirl, fuel burn, and exhaust flow. The engine upgrade process also resulted in the compression ratio being lowered from 16.5:1 to 16.0:1 to improve emissions and overall efficiency, according to Mauro Puglia, the head of diesel engineering for VM Motori and the chief engineer for the EcoDiesel.
Puglia says the V-6's dual overhead cams are also new, but they have the same the lift, duration, and valve timing as the previous-generation EcoDiesel. What's different is the cam lobes are narrower and the 'shafts are lighter than those in the earlier model as part of the engineering effort to reduce engine weight and improve power by reducing parasitic losses wherever possible.
The VM Motori engineers upgraded the injectors from six- to eight-hole servovalve models that are part of Fiat's proprietary MultiJet II high-pressure, common-rail diesel fuel injection system, and they also slipped on the latest generation's water-cooled, variable-geometry turbine (VGT) turbocharger built by Garrett Advancing Motion.
The new turbo has lighter blades and more efficient housing designs, making it faster spooling, and it pushes boost up to 29.7 psi compared to the earlier generation's 26 psi. (This 14 percent jump in turbo boost compensates for the lower compression ratio, and it plays a big part in the new EcoDiesel's gain in torque and horsepower.)
The new EcoDiesel's fuel delivery is still handled by a Bosch CP4-series high-pressure fuel-injection pump, gear-driven off the exhaust camshaft. It's been a trouble-free system used by both VM Motori on the previous EcoDiesels as well as by Cummins on the EcoDiesel's 6.7L big brother. The high-pressure pump fills both fuel rails at 29,000 psi. The 2020 Ram pickups still retain the low-pressure lift pump in the fuel tank to help push fuel to the high-pressure fuel pump, helping relieve some of its workload.
Where the fuel system has changed the most on the Ram 1500 diesels is on the air delivery side. In the past, the charge-air cooler (CAC) was "stacked" in front of the radiator. Now the EcoDiesel employs a new CAC in the same configuration as the 6.7L Cummins, where it's located below the radiator and behind the opening in the front bumper, separate from the radiator, transmission cooler, and A/C condenser.
"This maximizes our ability to both improve and control the airflow from the turbo to the intake, and minimize engine heat buildup of a 'stacked' layout," explained Chief Engineer of the Ram 1500 Rod Romain. He pointed toward the front bumper of the Rebel we were driving and said the new cooling layout now employs two separate, electrically actuated, computer-controlled Active Air Shutters—one for the CAC; the other for the conventional radiator stack.
The new cooling configuration allows the EcoDiesel's computer system to open and close the shutters independently to meet the engine and turbo cooling needs and to minimize aerodynamic wind drag when the shutters are closed.
EGR System Refined
On the emissions side, the new EcoDiesel employs a dual-loop exhaust gas recirculation (EGR) system with individual EGR coolers. The addition of a low-pressure side, which draws exhaust gases as they exit the diesel particulate filter (DPF), minimizes turbocharger energy losses while helping increase fuel economy under certain driving conditions.
"The dual-loop EGR helps both power and fuel economy," said Puglia. "For example, in high-load, high-speed conditions the low-pressure EGR system isn't capable of providing enough flow rate to maximize the turbocharger efficiency, which is why we now have the high-pressure loop (it draws exhaust gases from the manifold) helped by the low-pressure side. The high-pressure EGR also helps the low-pressure side in conditions where the ambient temperature is very low. When the engine is warm and under normal driving conditions, the low-pressure side is now doing most of the work."
Ram diesel engineers say the addition of cooler, low-pressure exhaust gases makes a "significant contribution to improved fuel economy and lower oxides of nitrogen (NOx)." The rest of the diesel's emissions system and layout downstream from the dual-loop EGR is carryover from the previous model.
Puglia pointed out a few more changes to the third-gen EcoDiesel as we circled a static display. The oil cooler mounted to the outside of the block is of the newest design with better flow and cooling efficiency, even though it looks very similar to the one used on the "old" engine. The oil pan of the 60-degree V-6 is now baffled, and it's made from a lightweight polymer/metal material that dissipates heat better while helping in the reduction of what vehicle engineers refer to as NVH (noise, vibration, and harshness).
Ram has also applied electrical engine accessory components instead of beltdriven ones in an effort to reduce frictional losses. The fan is electric, as is the water pump. And the new engine is using a more efficient, dual vacuum pump system for the brakes—one cam-driven, the other electric.
On the transmission side, the '20 Ram EcoDiesel utilizes the same TorqueFlite 8HP75 eight-speed automatic as the 5.7L Hemi, with different torque converter and shift calibrations, of course, to match up with the lower operating rpm and torque curves of the new EcoDiesel engine. From there back, the drivetrain is identical to what is offered in the Hemi.
On the Road
We spent the better part of a day driving more than 200 miles in different configurations of the Ram 1500 diesel, including a short off-road stint in the Ram Rebel. The diesel version of Four Wheeler's 2019 Pickup Truck of the Year didn't disappoint. Having more torque than a 5.7L Hemi available at 1,600 rpm is a real treat when facing steep climbs, powering through mud, easing over rough terrain, or taking on just about any other off-road terrain or obstacle. It's torque that gets a load moving, and the 480 lb-ft the 3.0L EcoDiesel has on tap does so with aplomb in a '20 Ram Rebel 4x4.
It's quiet power, too, which makes long road trips and in-cab conversations very pleasant. The only noise in the cab of the Rebel we were driving was the whine from the all-terrain tires. Driving Rams shod with street treads, the new diesel is so quiet at times we thought it'd shut down. Even when parked the only hint there's a diesel under the hood is the soft, muffled rattle—almost like marbles being jostled in a velvet-lined shoebox.
There's no obvious turbo "lag," either. Drop the hammer from a stop sign and the 3.0L scoots. The eight-speed automatic's shift points are spot on, and the engine pulls hard all the way to around a 4,200-rpm shift point. The power curve feels flatter than that of the previous EcoDiesel, and we didn't notice any fall off in power all the way to highway speeds. It doesn't feel quite as fast as the new Duramax 3.0L, nor does our initial drive impression place it as fuel efficient. But those are just impressions—not hard data. What we did observe for highway fuel economy running 60-65 mph between Duluth and Gilbert, Minnesota, was 31-33 mpg (indicated) while driving a 2WD Tradesman and 28-30 mpg (indicated) behind the wheel of a Crew Cab Rebel. It'll be interesting to see what the EPA numbers show, which should be released before the EcoDiesels go on sale in Q4 of 2019.
Where It Fits
Our overall impression is the refinements VM Motori has done on the '20 3.0L EcoDiesel make for an impressive engine option for those who want both towing power and fuel economy. It's an ideal engine for a Rebel, providing excellent fuel economy and plenty of low-end power to handle just about any off-road adventure. Get it with the optional 3.92 axle ratio and it'll handle a lift and bigger tires with ease.
That same combination is great for towing toys, too. We towed a trailer loaded with a pair of side-by-sides and another with a 24-foot ski boat. Both trailers were near 5,100 pounds (well below the Ram 1500's max rating on some models of 12,560 pounds.) The EcoDiesel handled both trailer combinations with ease, getting up to interstate speeds seemingly almost as quickly as one would have with the 5.7L Hemis—and with towing fuel economy in the low double digits (indicated).
For the four-wheeler who does occasional towing and a lot of commuting, the '20 EcoDiesel option looks like a bargain: The premium for the EcoDiesel is $4,995 USD over the standard 3.6L Pentastar V-6 featuring the eTorque system, $3,300 over the 5.7L Hemi V-8, and $3,000 over the 5.7L Hemi V-8 with eTorque.
Diesel or gas, the '20 Ram 1500s are backed with a five-year/100,000-mile Powertrain Limited Warranty. That warranty covers the cost of all parts and labor needed to repair a covered powertrain component—engine, transmission, and drive system.
It should be noted that a good portion of that diesel premium should be recouped at trade-in or resale time, as diesels command higher resale prices than their gas counterparts.
Quick Specs (as tested)
Vehicle/model: '20 Ram 1500 Rebel Crew Cab
Base price: $47,995
Engine: 3.0L EcoDiesel V-6
Rated hp/torque (lb-ft): 260/480
Transmission: TorqueFlite 8HP75 8-spd auto
Transfer case BorgWarner 48-12
4WD system: 2-Hi, 4-Hi, Neutral, 4-Lo
Low range ratio: 2.64:1
Frame type: Ladder
Suspension, f/r: Upper and lower A-arms, air springs/five-link with track bar, air springs, stabilizer bar
Axle ratio: 3.92:1
Max crawl ratio: 48.7:1
Steering: Power-assisted rack-and-pinion
Brakes, f/r: 14.9-in vented disc, two-piston caliper/14.8-in disc, single-piston caliper
Wheels (in): 18x8
Wheelbase (in): 144.6
Length (in): 232.9
Height (in): 77.6
Width (in): 82.1
Base curb weight (lb): 5,502
Approach/departure angles (deg): 26.7/23.8 (raised suspension)
Minimum ground clearance (in): 10.3 (raised suspension)
Payload (lb): 1,600
Max towing capacity (lb): 11,330
Fuel capacity (gal): 33.0
Fuel economy (EPA mpg, combined city/hwy/trail): N/A
Fuel economy (observed/hwy): 28-30 mpg