Return of the Slant-Six: Why Dodge’s I6 ‘Tornado’ Engine Will Trigger Mopar Nostalgia

The new Hellcat’s out of the bag: Stellantis is developing a turbocharged inline six-cylinder. The I6 engine belongs to the company’s global medium engine (GME) family, which includes the current Wrangler’s I4. It is likely to replace the 5.7-liter V8 HEMI, even in North America. Fans of MOPAR muscle may be quick to adopt an I6, thanks to one of the best-known Dodge classic car engines of all time.

The tale of the unkillable slant six

1963 Dodge Dart with a slant-six engine. The new Stellantis I6 may trigger MOPAR nostalgia. | Henry Cesari/MotorBiscuit
1963 Dodge Dart with a slant-six engine | Henry Cesari/MotorBiscuit

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Dodge’s slant-six engine inspires a surprising amount of devotion. The slant-six was far from a performance engine. In fact, this powerplant, known internally as Chrysler Corporation’s “G-engine,” was the cheapest option available in countless cars from 1959 through 1987.

Because MOPAR offered the slant-six for so long, this engine still powers countless classic cars. Therefore, many mechanics know how to work on them. Slant-six-powered Dodges and Plymouths are considered some of the easiest classic cars to restore. In addition, the slant-six is relatively simple and overbuilt. Slant-six equipped vehicles are among the most reliable classic cars.

Dodge built a straight-six, flathead engine from 1925 through the 1950s. By the 1950s, the company decided to build an all-new powerplant for its entry-level vehicles. Engineers designed another inline-six in both a 2.8-liter and 3.7-liter displacement. Rumor has it that vehicle designer Virgil Exner insisted on a low, “European” hood line for the early Plymouth Valiants. Therefore, engineers inclined (or “slanted”) the engine’s cylinder bank 30 degrees.

Dodge first cast slant-six blocks out of aluminum. By the engine’s second year of production, the company switched to cast iron. The result is a thick, strong cylinder block that is partially responsible for the engine’s steadfast reputation.

Rise of the GME T6 “Tornado”

2021 Jeep Wrangler and Renegade. The new Tornado I6 is rumored to fit in the Wrangler. | Stellantis
2021 Jeep Wrangler and Renegade | Stellantis

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Dodge replaced the slant-six with a V6 for the 1987 model year. Since then, Dodge has built several V6s. This includes the now ubiquitous Pentastar V6. But fans of the old inline-six Dodge engines were elated to hear of a new, turbocharged I6 in the works.

The new twin-turbo straight-six belongs to the Stellantis global medium engine (GME) family. For this reason, it will share many design elements with the new I4 available in the Jeep Wrangler. Rumor has it that the new I6 will also be small enough to fit under the Wrangler’s hood.

Stellpower reports the new I6 engine project carries the “Tornado” name. This is in line with the company’s tradition of naming engine projects after airplanes (i.e. Apache, Hurricane). The engine is currently an Alfa Romeo project, but may be built in a U.S. factory.

The rumored output goal for the Tornado is 400 horsepower. This would require precise tuning of the twin turbos and perhaps an eTorque engine mild-hybrid setup, similar to the current Ram trucks. Such an engine could oust the 5.7-liter HEMI in whatever vehicle replaces the current canceled Charger chassis.

What’s with all the six cylinders?

2022 Dodge Challenger and Charger. The tornado I6 may make 400 horsepower and replace the 5.7-liter HEMI. | Stellantis
2022 Dodge Challenger and Charger | Stellantis

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It seems more and more automakers are replacing V8 engines with turbocharged six cylinders. First, Ford’s SVT engineers shocked the world by ditching the F-150 Raptor’s V8 in favor of an EcoBoost V6. More recently, Toyota tossed the V8, and now a turbocharged V6 powers every 2022 Tundra truck.

Dodge may just be the next automaker to swap its V8s for powerful and fuel-efficient turbocharged six-cylinder engines. But fans of the unkillable slant-six will be tickled to see a descendant of the “little engine that could,” replacing the mighty HEMI V8.

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