MC&T Staff 
The all-new, three-row 2021 Jeep Grand Cherokee L offers shoppers a choice between two familiar powerplants, this time with more refinement and better fuel economy. Expect the same for the two-row, 2022 Jeep Grand Cherokee when it’s revealed later this year.
Standard equipment is the tried and true all-aluminum 3.6-liter Pentastar V6 engine, rated at 290 horsepower and 257 lb.-ft in this application. The compact 60-degree V6 has long been a workhorse for Jeep, taking home a Wards 10 Best Engines and Propulsion Systems award seven times over its life.
Power, refinement, and smoothness are the name of the game in the 2021 Jeep Grand Cherokee L. The dual overhead camshafts are chain-driven and feature a two-step variable valve lift and variable valve timing system that allows the powertrain control module to rapidly tailor engine behavior to vehicle dynamics and driver demand. The aluminum Pentastar boasts a bore x stroke of 3.78 x 3.27, an 11.3:1 compression ratio, and a max engine speed of 6,700 rpm.
The cam phasing also enables better fuel efficiency and widens the Pentastar’s torque band. Nearly 90 percent of the engine’s peak torque is available from 1,800 to 6,400 rpm. All that adds up to a rated towing capacity of up to 6,200 pounds, and an estimated driving range of nearly 500 miles, which Jeep claims is a class-leading figure.
Like everything, the Pentastar V6 features engine start-stop technology as standard equipment. There’s a new pressure reserve chamber within the bell housing of the transmission which retains and provides transmission fluid to the gearset at engine restart for a quicker launch. Additionally, engineers refined the powertrain controls and starter technology to reduce engine restarts from mild movements of the driver’s foot on the brake pedal.
Naturally, buyers looking for more thump in the 2021 Jeep Grand Cherokee can always opt for FCA’s superb 5.7-liter Hemi V8, which comes rated at 357 horsepower and 390 lb-ft of torque in this application. The Hemi V8 employs a cast-iron block and aluminum cylinder heads, has classic pushrod-operated overhead valves, and sports eight deactivating and eight conventional hydraulic lifters, all with roller followers, plus it packs VVT and cylinder deactivation technology. The 90-degree V8 sports a bore x stroke of 3.92 x 3.58, and a 10.5:1 compression ratio. Max engine speed is a truck-like 5,800 rpm.
As in previous years, the PCM will shut down the fuel and spark going to four of the eight cylinders during light-duty operations such as highway cruising or noodling around town. The dormant cylinders fire back to life as soon as the driver demands more power and torque than the engine is capable of delivering at half-mast. Jeep says the system has a wider operating range than it did previously and can increase fuel economy from 5 to 20 percent in the case of the 2021 Jeep Grand Cherokee L.
The VVT system benefits from new refinements as well. New logic helps reduce pumping losses by closing the intake valve later which in turn enhances burn and allows more of the combustion event to spin the crank instead of exiting as heat through the exhaust valve. This all adds up to a class-leading towing capacity of up to 7,200 pounds for the 2021 Jeep Grand Cherokee L.
Both engines are joined with the FCA’s TorqueFlite eight-speed automatic transmission, which is sourced from ZF and packs on-the-fly shift-mapping which allows the transmission to better match the attitude of the driver in all situations.
Lastly, both 2021 Jeep Grand Cherokee L 4×4 powertrains come equiped with a new front axle disconnect system. It’s a simple enough algorithm that disconnects the front axle (which is now mounted directly to the engine to better reduce NVH) when the vehicle senses that road conditions do not require full-time all-wheel drive. With the truck now in two-wheel drive there’s less driveline drag which in turn boosts fuel economy.
Eventually, there will be a 2021 Grand Cherokee 4xe model as well, which should see the 3.6-liter Pentastar V6 joined with a pair of electric motors to offer silent electric driving, much like we’ve already seen from the Wrangler 4xe. Of course, it goes without saying that we here at MC&T are eagerly looking forward to the next generation of SRT Grand Cherokee models.
– By Michael Accardi
