Mahindra and Lightweighting: Solid Steel To Nimble Aluminum

Over the past two decades, Mahindra has systematically reengineered its powertrain architectures — spanning internal combustion engines (ICEs) and electric drivetrains — to slash weight, boost thermal efficiency, and future-proof platforms for stringent regulations like India’s BS6 and upcoming CAFE norms. This lightweighting journey wasn’t driven by a single breakthrough but by a meticulous, phased overhaul of mechanical packaging, material choices, manufacturing techniques, and system-level integration.

ICE Powertrains Get a Diet

Mahindra’s early diesel engines were cast iron workhorses, built for durability but burdened by weight. The transformation began with the introduction of the firstgeneration mHawk engine in 2007, which featured parent bore construction and improved weight-to-performance ratios. The real leap, however, came a decade later with the second-generation mHawk.

“We were the first Indian OEM to use an aluminum block in a high-powered diesel engine,” said Dhananjay Rao Boita, Chief Engineer, Powertrain Division, Auto Sector Mahindra & Mahindra. The switch from cast iron to a deepskirt aluminum cylinder block in the 2017 diesel lineup delivered a staggering 65 kg weight reduction — without sacrificing power, torque, or structural rigidity. The secondgeneration engine offered 30–40% higher performance while shedding significant mass.

“We increased the power by 30% and torque by 40%, but the weight was reduced by 50 kg,” Boita explains. This lightweighting extended beyond the engine block. Cast iron brackets were replaced with aluminum, and in the latest generation, eliminated entirely in favor of direct mounting solutions. Technologies like hollow steel camshaft and integrated oil cooler-filter modules further trimmed mass, aligning with global trends toward efficiency-driven design.

The Compact Petrol Strategy

In its gasoline strategy, Mahindra prioritized power density over engine displacement. Naturally aspirated engines typically delivered 50–55 kW/L, but turbocharged GDI (gasoline direct injection) variants now achieve 80–85 kW/L. “Downsizing with high power density was a gamechanger. Our 1.2L turbo now replaces heavier 1.5L or even 2.0L naturally aspirated units.”

To maintain output while reducing mass, Mahindra introduced architecture-level innovations, such as integrating the exhaust manifold into the aluminum cylinder head. This not only saved weight but also improved thermal management, ensuring Lambda 1 operation by controlling exhaust temperatures. This approach mirrors strategies employed by global leaders and tailored for India’s unique market demands.

Electric Vehicles: When Every Gram Counts

As India accelerates toward electrification, with government targets aiming for 30% EV penetration by 2030, lightweighting is crucial in EVs, where battery mass is a significant factor. For its Born Electric (BE) lineup, Mahindra selected blade cells with 190 Wh/kg energy density — the highest in the lithium iron phosphate (LFP) chemistry segment. “Cell-to-pack architecture helped us achieve 141.5 Wh/kg at pack level — the highest energy density in this category.”

By bypassing the traditional cellto- module-to-pack approach and adopting a direct cell-to-pack design, Mahindra eliminated intermediate structures, saving space and weight. Battery enclosures became a key focus. For the BE6 and XEV 9E SUV’s battery pack, Mahindra opted for aluminum extrusions (5000 and 6000 series) over steel. Even the bottom cover, vulnerable to stone impacts, was reengineered.

“We shaved off 13–15 kg by switching to aluminum battery covers with laser-welded reinforcements over steel," Boita said. Mahindra partnered with leaders in lightweight materials, to deploy laserwelded aluminum stampings, balancing cost, strength, and weight.

The 3-in-1 EDU and the Future of e-Drivetrains

As electric vehicles (EVs) mature, system-level integration has become a cornerstone of efficiency. Mahindra’s latest Electric Drive Units (EDUs) feature a three-in-one system, combining the motor, gearbox, and inverter in a single housing. “Earlier, the motor, gearbox, and inverter had separate housings connected by cables. Now, in our latest generation, we use a three-in-one combined EDU.” The center housing is a single casting, with only the PCB board added externally, yielding a 10% weight reduction at the e-drive level.

Mahindra also tackled smaller components, replacing traditional screws and bolts with flow-drill screws, RIVTAC rivets, and bonding technologies. “It’s not just the big parts. Even fasteners and joints matter — we use bonding, flow-drill screws, and RIVTAC to save weight without losing integrity.” This attention to detail positions Mahindra alongside global EV pioneers like Tesla and BYD in system-level optimization.

Materials Matter: Aluminium, Magnesium, and Plastics

Mahindra has embraced aluminum alloys across its powertrain systems — from cylinder heads and blocks to transmission housings and battery enclosures. These materials benefit from India’s robust supplier ecosystem for castings and extrusions. “From cam covers to intake manifolds, we’ve replaced metal with high-performance plastics wherever possible.” Reinforced plastics and composites have supplanted metal in intake manifolds and cam covers and are now being explored for oil sumps and large-format battery housings.

However, materials like magnesium and high-rare-earth (HRE) magnets (neodymium-based) pose challenges. “Magnesium is promising, but supply is limited, and infrastructure is niche — India needs to invest to scale.” Magnesium’s flammability and corrosiveness require specialized casting environments, limiting its adoption. Still, Mahindra sees long-term potential, particularly as India aims to reduce dependence on imported materials.

Platform Thinking and Circularity

Mahindra’s INGLO platform, underpinning four to five future EVs, is central to scaling lightweight components cost-effectively. “Our INGLO platform is a scalable base — four to five vehicles share it, giving us the manufacturing scale to justify lightweight investments.” Localization and circularity are strategic priorities. Mahindra advocates regional supply bases for advanced materials and improved recycling infrastructure. “We must localize critical materials and invest in circularity if we want to de-risk future supply chains.” This focus on sustainability aligns with the efforts of global OEMs to build resilient, circular economies.

EV to ICE and Back Again

Mahindra believes that lessons from latest battery and electric powertrains — in materials, thermal integration, and lightweight design, advanced bonding and joining techniques — can be implemented. “There are areas where EV learnings can go back into ICE. It’s something we’re actively looking at.” As India navigates a multi-powertrain future and EVs and ICE vehicles are expected to coexist with EVs through 2030, Mahindra’s powertrain engineering demonstrates that systematic weight reduction is no longer just a design goal — it’s a competitive imperative.