Stellantis unveils its new Turbo Inline-Six engine: discover “the hurricane”
It’s not the “Tornado”, but this new engine is still a force to be reckoned with.
With all the talk about electric vehicles and change a way of internal combustion development, it’s certainly a change of pace to see an all-new engine emerge. And yet, that’s exactly what we have here, as Stellantis finally unveils its all-new hurricane 3.0-litre straight-six. It’s the first clean sheet engine launched by the automaker in some time, and it’s intended to deliver V8 levels of power, while significantly reducing CO2 emissions and improving fuel economy.
So what’s true about the previous rumors and what’s changed from what we thought we knew?
Two separate 400 to 500 horsepower motors
Global Propulsion Manager Micky Bly gave a substantial overview of Stellantis’ new powertrain, as well as why the company developed it in the first place. Engineers began working on this design in 2019, and the first GME-T6 (Global Medium Engine – Turbo 6) units actually entered production at the company’s factory in Saltillo, Mexico in November 2021. Bly noted that while Stellantis is turning full throttle towards electric transmissions, the specific needs of their customers still require an internal combustion solution, at least in the short term.
To meet these needs, the Hurricane 3.0-liter inline-six will arrive in Stellantis vehicles later this year, in two tuning states. The “SO” (standard output) engine, according to the company’s official statement, will produce “over 400 horsepower” and 450 lb-ft of torque, per SAE J2723. The company notes that it has further optimized the unit for efficiency, with two smaller turbochargers, lower maximum boost pressure (22 psi) and a higher compression ratio of 10.4:1. The Hurricane engine SO can run on 87 octane fuel, although the automaker recommends a premium for the best possible numbers.
The ‘HO’ – or High Output – engine will produce “over 500 horsepower” and over 475 lb-ft of torque. This version uses larger turbochargers and produces a higher maximum boost (26 psi). Engineers tuned this powertrain for performance and thus lowered the compression ratio to 9.5:1. The Hurricane HO requires premium fuel, while the 350 bar (5,075 psi) direct injection system delivers gas to each of the six cylinders via two chain-driven pumps (one on the SO engine).
Stellantis says both motors have a wide, flat torque curve between 2,850 rpm and redline. On the SO version, the redline is electronically limited to 5,800 rpm, while the HO motor spins up to 6,100 rpm.
Both Hurricane engines share several components
In an effort to increase production – Stellantis aims to build up to 250,000 of these engines each year at their engine plant in Saltillo North – the SO and HO versions of the Hurricane straight-six share 96 common parts. The differences between the two motors mainly relate to changes in power or application. Components such as turbochargers, intercoolers and a few other minor changes will be different between the two engines.
Both versions of the Hurricane 3.0-litre straight-six use a lightweight, deep-skirted cast-aluminum block with cross-bolted steel main bearing caps. The engines also use a die-cast aluminum alloy oil pan and head as well as a pitched roof combustion chamber (do not hemispherical). The crankshaft and connecting rods are forged steel, while the pistons themselves are forged aluminum alloy.
A notable change with the new Hurricane engine design is its cylinder liner. Instead of cast iron, cast steel or forged alloy cylinder liners, Stellantis’ new engine uses “Plasma Transfer Wire Arc” (or spray bore) technology to spray each cylinder with a permanently bonded coating. The process melts a steel alloy wire at 2,300 degrees Celsius (4,150 degrees Fahrenheit), then sprays microscopic particles directly onto the walls of the cylinder. After extensive durability testing, Bly claims that the PTWA coating provides 10 times better wear resistance, as well as improved efficiency through reduced friction losses for individual pistons.
These engines share a common bore and stroke (3.31 x 3.54 inches or 84 x 90 mm), as well as similar cylinder spacing to Stellantis’ existing 2.0-liter turbocharged four-cylinder engine, currently used in the Jeep Wrangler, Cherokee and Grand Cherokee 4xe.
The Hurricane may be electrified, but it won’t be at first
Overall, Stellantis claims the Hurricane 3.0-liter inline-six alone will reduce CO2 emissions from the company’s long-life 5.7-liter Hemi V8 by 13-15 percent. On top of that, even the SO version will offer more power and torque, at 133 horsepower per litre. The HO engine, for its part, can manage at least 166 horsepower per liter, according to the manufacturer’s preliminary specifications.
Exact Power and torque values depend on the specific application. Stellantis plans to roll out this engine across all of its North American brands, with the most likely candidates to receive this engine first being the Ram 1500 and Jeep Wagoneer/Grand Wagoneer. Company spokespersons haven’t confirmed where you’ll see the hurricane first – those announcements are coming in the coming months. However, in the future, the Hurricane will equip the “STLA Large” and “STLA Frame” platform vehicles.
Neither version of the Hurricane will be electrified at launch. Both versions of the Hurricane engines hitting dealerships later this year will have an engine start and stop feature, again to improve fuel economy.
That said, engineers designed the engine with electrification in mind, so it can support HEV or plug-in hybrid applications. That will likely come into play as emissions regulations continue to tighten, but the byproduct of that could be even more horsepower and torque down the line.
Stay tuned for more news!
This week’s Hurricane reveal is just the tip of the iceberg, and we should have a lot more brand-specific information over the next few months. Stay tuned to TFLtruck for all this information as soon as we have it.