For nearly two decades, Chrysler’s Gen III Hemi has provided motivation for a wide range of different high-powered Mopars. Everything from Ram trucks to Dodge Challengers have benefited from different iterations of this charismatic pushrod V8 over the years, but as federal regulations continue to tighten and the industry marches toward electrification, big displacement engines are quickly being phased out in favor of smaller, more sophisticated powerplants.

This trend has been a source of frustration for some enthusiasts, but in the case of Stellantis’ new Hurricane 3.0-liter engines, it’s hard to argue with the numbers. The power plants come as part of Stellantis’ commitment to cut its carbon footprint in half by 2030 and are said to offer significant improvements in both power and fuel economy over the 5.7-liter and 6.4-liter Hemi V8s that they’re expected to replace throughout the company’s portfolio.

While the twin-turbocharged mills boast state-of-the-art technology and inherently smoother operation thanks to their inline six-cylinder configuration, it’s also clear that they have very big shoes to fill. To prove the new engines’ worth, Stellantis invited us out to Bozeman, Montana to get some seat time with the new Hurricane I6s on the road and out in the dirt in Jeep’s latest full-size sport-utilities.

The standard output and High Output Hurricane I6 engines look virtually identical in the engine bay of the Wagoneer and Grand Wagoneer. The silver “Twin Turbo” lettering on this engine cover is perhaps the easiest way to identify this as the High Output version at a glance.

The 3.0-liter, DOHC Hurricane I6 will initially be available in two different flavors: A standard output version, which offers 420 horsepower at 5,200 RPM and 468 pound-feet of torque at 3,500 RPM, and a High Output version that dishes out 510 horsepower at 5,700 RPM and 500 pound-feet of torque at 3,500 RPM. The boosted, all-aluminum engines feature a pair of low-inertia, high-flow turbos that feed three cylinders each to optimize throttle response. The standard output engine can see peak boost pressures as high as 22 psi, while the High Output version can reach up to 26 psi.

Both engines utilize a high-pressure direct injection fuel system which operates at 5,075 psi. A single fuel pump with a dedicated chain-driven shaft is used in the standard output engine; the High Output version uses a dual-pump setup. Fully independent variable valve timing, a water-to-air charge cooler, and automatic engine stop-start functionality are pretty standard fare in modern forced induction engines, but features like the low-friction Plasma Transfer Wire Arc coating in the cylinder bores and high-flow ball-valve thermostat – the latter of which minimizes restriction in the cooling system to reduce mechanical losses – seem a bit more exotic by American engine standards.

The engines look virtually identical to one another when installed in an engine bay, with the silver “Twin Turbo” lettering on the High Output version’s engine cover being the most obvious giveaway at a glance. The HO motor has a few internal upgrades to contend with the additional boost, though, like forged aluminum pistons with an anodized top ring land and a diamond-like coating on the pins to minimize friction. The Hurricane High Output also has a 9.5:1 compression ratio and requires 91 octane premium fuel, while the standard output engine has a 10.4:1 compression ratio and can run on 87 octane (although 89 octane is recommended). If you want to know more about the design of these new engines, be sure to check out our Hurricane I6 deep dive.

Going Long

The standard wheelbase Grand Wagoneer (left), and the Grand Wagoneer L.

Jeep’s Wagoneer L and Grand Wagoneer L sport-utility vehicles will be among the first to utilize these power plants, with the standard output Hurricane I6 replacing the 5.7-liter V8 in the former and the HO Hurricane replacing the 6.4-liter Hemi in the latter.

The “L” in the model names denotes their extended length versus their standard counterparts. The wheelbase on L models increases by seven inches, while overall length grows by a foot to 226.7 inches. That puts these vehicles’ dimensions on par with the fifth-generation Cadillac Escalade ESV, but with curb weights that range from around 6100lbs in a base Wagoneer L to over 6700lbs in a fully-loaded Grand Wagoneer L, the Jeeps can have as much as 700 pounds of additional heft to lug around, so it’s clear that the Hurricane I6 has its work cut out for it.

All of the Wagoneer L and Grand Wagoneer L’s additional length is past the B-pillar. The longer rear doors are unique to L models. Long wheelbase Wagoneers and Grand Wagoneers also get up to 15.8 cubic-feet of additional storage space behind the third row.

We started the day off on the highways and rolling hills around Bozeman in a Grand Wagoneer L Series II. While the High Output version of the Hurricane I6 is optional in the Wagoneer, it’s standard on all Grand Wagoneers, so our first taste of the new engine was with the hotter version.

Aside from its extended length and new powerplant, this Grand Wagoneer L was equipped very similarly to the one we drove from LA to Vegas and back for LS Fest West this past April. That’s another way of saying it was a positively baller machine, outfitted with supple leather on the driver and front passenger’s heated and ventilated massage seats, along with no less than four separate high-resolution displays up front and an absolutely killer 23-speaker, 1,375-watt McIntosh audio system. It feels every bit like a proper Escalade rival, and considering what these big brutes cost, it certainly should: While base Wagoneer pricing starts at $65,495, a Grand Wagoneer can command as much as $111,990 in Series III trim before you tack on any additional options.

When we drove the standard wheelbase Grand Wagoneer we noted that the 6.4-liter Hemi had no problem getting the big SUV moving in a hurry and provided plenty of passing power at freeway speeds. It was also a big improvement over the aging 5.7-liter V8 that we tested in the fifth-generation Grand Cherokee last year, which seemed a bit stressed when called upon to overtake slower traffic, even though it was in a significantly lighter vehicle.

Regardless of which version of the Wagoneer family you choose, capacity won't be an issue. The Grand Wagoneer L boasts a cargo capacity of 44.2 cubic feet of storage behind the third row of seats.

Compared to the 6.4-liter Hemi, the Hurricane HO offers gains of 39hp and 45lb-ft. At the helm the difference in peak output isn’t transformative – the Grand Wagoneer L’s extra weight versus the standard wheelbase model is probably to blame for part of that – but the turbocharged six-cylinder definitely has no problem keeping up with the big, naturally-aspirated V8 when it comes to mid-range grunt.

Boost comes on early, with the HO engine developing 90% of its peak torque output at just 2,350 RPM. You can find hints of turbo lag here and there when rolling onto the throttle at lower speeds, but you really have to be actively looking for it, and once the engine revs are above 3,000 RPM, the response is very linear all the way to the engine’s 6,000 RPM redline – much like the Hemi. But also like the 6.4-liter V8, the High Output Hurricane can get pretty thirsty if you’re not judicious with the throttle: We saw just under 18 mpg in mixed driving with a few wide-open acceleration tests thrown in along the way. Where the High Output Hurricane really makes its case is how effectively it blends in with this particular application. While the V8 made its presence known whenever you asked for some additional grunt, the Hurricane is much smoother and quieter while it does its work. In that way it feels like a more ideal power plant for something like a Grand Wagoneer, a vehicle in which potential customers might not want a boisterous engine distracting from an otherwise luxury-focused driving experience.

The bigger difference seems to be the transition from the 5.7-liter Hemi that was used in the ‘22 Wagoneer to the standard output Hurricane that replaces it as the default engine in the ’23 Wagoneer. We didn’t have a chance to check out the 5.7-liter in the Wagoneer last year, which was equipped with an eTorque mild hybrid system and offered up 392 hp and 404 lb-ft, but it’s a noticeable improvement over the version of that V8 in the Grand Cherokee despite the Wagoneer’s extra half-ton of weight. Around town at lower speeds its response nearly matches the High Output engine, and it’s not until you go to make a pass at Montana highway pace that the difference in power really becomes noticeable between the two versions of this new engine. Both the Wagoneer L and Grand Wagoneer L offer best-in-class towing, but the 2WD Wagoneer L with the standard output engine actually offers the highest rating at 10,000 pounds. That figure drops to 9,850lbs on four-wheel drive models with the standard output engine, while models outfitted with the HO Hurricane are rated for a maximum of 9,450 pounds.

The front of the Grand Wagoneer’s cabin is brimming with screens. Our tester featured a 12.3-inch digital gauge cluster, a 12-inch touchscreen for infotainment, 10.25-inch touchscreen below it that’s exclusively for seat adjustments, and a 10.25-inch display for the passenger.

Jeep also gave us a chance to check out how the new engines do out in the dirt with some models that were outfitted with the Advanced All-Terrain Group. Available only on standard wheelbase Wagoneers and Grand Wagoneers, the package includes 18-inch wheels with all-terrain rubber, a two-speed transfer case, a 3.92 rear axle ratio, air suspension, skid plates for the front axles, transfer case, and fuel tank, and a few other off-road goodies.

The Wagoneer might not wear a Jeep badge anywhere on it, but this hardware certainly allows it to perform like one, as it might short work of the ruts, streams, and rocky hill climbs that we encountered along the trail. And while some turbocharged engines can leave you wanting for power at crawling speeds, the availability of 4WD Low ensured that the engine was on boost the moment we dipped into the throttle, providing immediate power when needed without any sense of nervousness in its response.

Although it may lack the rowdy personality that has come to define the Hemi in recent years, when it comes to luxury sport-utilities and trucks, this boosted inline six is actually better suited to the task. And of course we’d be remiss if we neglected to point out that the presence of factory turbochargers makes these engines ripe for aftermarket tuning. We’ll certainly miss the roar of a naturally aspirated V8 in a big SUV like this, but all things considered, it’s hard to find much fault in its replacement.