While the auto industry has seen a downsizing trend with the V12 becoming a rarity, V10s counting on one hand, and V8s being replaced by smaller units, the inline-6 engine is witnessing a remarkable resurgence.

Contrary to the shrinking engine landscape, straight-six powertrains are gaining traction and may just be the worthy successor to the once-dominant V8, particularly as epitomized in the upcoming 2025 Dodge Charger Sixpack.

The inline-6 engine, which nearly became extinct in favor of V6s, has now become a logical choice for modern vehicles.

Cummins highlights the cost-effectiveness of inline-6 engines, pointing out their simpler manufacturing process with fewer internal parts and only one cylinder head and exhaust manifold compared to V6s. This simplicity not only streamlines production but also enhances reliability.

BMW has leveraged the scalability of inline-6 engines by sharing most internal parts with inline-4 engines, simplifying manufacturing and reducing costs.

Mercedes-Benz has adopted a similar modular approach, allowing the use of the same production line for different engine sizes.

This modularity has effectively positioned the inline-4/inline-6 combo as the new standard, replacing the older V6/V8 tandem in luxury vehicles.

The inherent smoothness of straight-six engines contributes to their appeal. They are longitudinally balanced and require no balancing shafts, offering a level of refinement even greater than V8s.

Toyota, known for the reliability of its inline-6 engines like the 2JZ-GTE, underscores this advantage. Similarly, Cummins has developed inline-6 diesel engines, celebrated for their toughness and durability.

The inline-6 engine is also designed to be more accessible for maintenance and repairs. With components like spark plugs and ignition coils readily accessible, and the clear separation of the exhaust and intake manifolds, repairs become less cumbersome compared to V-configuration engines.

Modern inline-6 engines excel in efficiency and emissions control as well. With fewer pistons to move and less internal friction, they convert more combustion energy to motion, making them more fuel-efficient than their V8 counterparts.

Mazda has introduced an inline-6 engine in its CX-90, aiming to elevate its brand to compete with German luxury automakers, suggesting the uniqueness and refinement of inline-6s are compelling even in the era of pushing toward electrification.

As the industry continues to evolve with electrification, the inline-6 has adapted well. Mercedes-Benz’s use of an integrated starter generator/alternator (ISG) in the M256 engine is a prime example, where electrification of auxiliary parts allows for a more compact design and enhanced turbocharging response.

The inline-6 engine’s suitability for turbocharging, demonstrated by Cummins, arises from its straightforward intake and exhaust plumbing.

This simplicity makes it a better fit for turbocharging, offering significant performance benefits while maintaining balance.

Relevant articles:
– The Inline-6 Engine Is Making A Comeback: Here’s Why, SlashGear
– Compared: Inline 6 vs. V6 Engines, capitalone.com
– Everything you need to know about inline-six engines, WhichCar, Apr 15, 2022
– What makes an inline 6 engine more reliable than a V6 or V8 configuration?, Eng-Tips Forums, Sep 6, 2018