The Bacalar spearheads a return to coachbuilding by Bentley Mulliner and features an enhanced version of Bentley’s peerless 6.0-litre W12 TSI engine, the most advanced 12-cylinder engine in the world.

Since the first introduction of the twin-turbocharger W12 in 2003, the engine’s refinement has seen an increase of up to 27 percent in power, 38 percent in torque and a reduction of 38 percent in emissions.

This has been realised through the evolution and optimisation of the crankcase, improvements in the oil and cooling systems, twin-scroll turbocharging technology and more effective injection and combustion processes.

Sources from Bentley told this correspondent that these improvements resulted from several initiatives taken by the company. It may be recalled that the latest generation of W12 was launched in the Bentayga in 2016. “A thoroughly reworked engine included a crankcase 30 percent stronger than its predecessor, while the cylinder surfaces were coated to reduce friction and improve corrosion resistance. A low-alloy steel coating is applied to the bores using an Atmospheric Plasma Spray (APS) process. Improvements were also made to the cooling system, with the engine featuring three separate coolant circuits. The first is designed to bring the cylinder heads up to optimum operating temperature as quickly as possible for best engine performance and low emissions. The second cool the engine block and oil system, while the third handles the turbochargers’ thermal load. Each system has a dedicated water pump, allowing optimised individual control,” sources said.

Twin-scroll Turbocharging

Twin-scroll turbochargers minimise turbo response time and provide a more efficient exhaust package. The exhaust assemblies for the three front and three rear cylinders are separate from one another, which feed the twin-scroll impellers. The turbocharger housing is welded directly to the exhaust manifolds and feature integrated speed sensors, allowing the engine to monitor turbo performance for maximum efficiency.

Effective Injection

The W12 combines high-pressure direct fuel injection (200 bar injection pressure) with low-pressure port injection (six bar). The combination of these two systems maximises refinement, lowers particulate emissions and optimises power and torque delivery.

Interestingly, each W12 engine is hand-built over 6.5 hours by a team of 45 craftspeople before undertaking a highly sophisticated test regime of over an hour via three specialist diagnostic machines during the engines assemble.

According to the sources, there were three specialist diagnostic machines with sophisticated test regime.

Leak Test

The leakage test is conducted by pressurising each of the systems for fuel, oil and water individually. The different cavities are pressurised to values between 0.2 – 5.0 bar respectively and then measured whilst the pressure decays over time. The reduction in pressure versus time represents the quality of the sealing of the engine assembly. If the pressure drops faster than expected, a leak is indicated. A special fluid is sprayed on to the exterior of the engine to pin-point any leakage paths.

Cold Test

The engine is loaded on to a testbed plate, and connections are made to the engine loom and all engine systems, whilst a large electric motor couples to the engine via the crankshaft. “Motoring” the engine via the crankshaft allows the testbed to collect data from a suite of sensors. The facility measures 600 individual properties and characteristics of the engine during a 15-minute cycle. Due to the low running speed of 120 RPM for the test, finer details and any inconsistencies can be identified thanks to a sample rate that highlights even the briefest of anomalies that would be invisible if the engine was firing or running at speed. This fine detail analysis is also valuable for confirming the precise timing of the engine. Using positioning information from sensors on the crankshaft, crankcase and camshafts, and cylinder compression values, the Cold Test can confirm the engine timing is accurate and, therefore, achieve the best possible combustion cycle.

Hot Test

When the engine arrives for hot testing, a UV dye is added to the engine to help identify any leaks. The coolant and fuel system are pressurised with air and nitrogen, respectively, for a final check before introducing the necessary fluids ready for testing. The engine is cranked to build oil pressure before the ignition system is energised and then left to idle whilst the engine test technician listens for any refinement issues and checks for leaks with a UV lamp. Sources said that each W12 is then tested for a minimum of 21.5 minutes and runs up to 3,800 rpm with a maximum load of 300 Nm. One in every one hundred engines receives a full eight-hour power test, achieving 6,000 RPM, and must achieve 900Nm.

The three tests that the Bacalar engine has already been put through are part of Bentley’s exceptional quality control processes. These testing procedures provide feedback on the quality of each engine and provide multiple checkpoints to catalogue the exact behaviour of each engine from the moment of manufacture. Since the installation of the three testbeds in 2002, over 100,000 W12 engines have been handcrafted in Crewe and passed through the test facility.

Technology Advancements

Bentley’s legendary 6.0-litre twin-turbocharged W12, created in 2002, has evolved into the latest iteration of the W12 engine used across today’s current model range. The unique W-configuration means that the engine is 24 percent shorter than an equivalent V12, benefitting packaging and maximising usable cabin space.

The latest generation of W12 was launched in the Bentayga in 2016. A thoroughly reworked engine included a crankcase 30 percent stronger than its predecessor, while the cylinder surfaces were coated to reduce friction and improve corrosion resistance. A low-alloy steel coating is applied to the bores using an Atmospheric Plasma Spray (APS) process.

The W12 combines high-pressure direct fuel injection (200 bar injection pressure) with low-pressure port injection (six bar). The combination of these two systems maximises refinement, lowers particulate emissions and optimises power and torque delivery.

Twin-scroll turbochargers minimise turbo response time and provide a more efficient exhaust package. The exhaust assemblies for the three front and three rear cylinders are separate from one another, which then feed the twin-scroll impellers. The turbocharger housing is welded directly to the exhaust manifolds and feature integrated speed sensors, allowing the engine to monitor turbo performance for maximum efficiency.

Bentley’s variable displacement system shuts down half of the engine under defined conditions. Intake and exhaust valves, fuel injection and ignition are all shut down on defined cylinders, with the engine running as a six-cylinder for improved efficiency. The system will run in this mode in gears three to eight, below 3,000 rpm and up to 300 Nm torque output.

The first Bacalar engine followed the same build process in Bentley’s centre of excellence for W12 engines, ensuring the same level of quality and expertise before final testing, sources added. (MT)

Sustainable, Recyclable Electric Motors

Bentley Motors has announced a three-year research study that aims to revolutionise the sustainability of electric motors. Supporting Bentley’s commitment to offering only hybrid or electric vehicles by 2026, the result could see recycled rare-earth magnets used in selected ancillary motors for the very first time.

The study, titled RaRE (Rare-earth Recycling for E-machines), intends to build on work completed at the University of Birmingham in devising a method of extracting magnets from waste electronics. The project will also scale up this process and repurpose the extracted magnetic material into new recyclable magnets for use within bespoke ancillary motors.

Adding to the sustainability benefits that RaRE will provide, the bespoke motors created through this method promise to minimise complexity through manufacture while supporting the development of the UK supply chain for both mass production and low volume components.

Dr Matthias Rabe, Member of the Board for Engineering, Bentley Motors, said, “As we accelerate our journey to electrification, offering only hybrid or electric vehicles by 2026, and full electric by 2030, it is important that we focus on every aspect of vehicle sustainability, including sustainable methods of sourcing materials and components. RaRE promises a step-change in electrical recyclability, providing a source of truly bespoke, low voltage motors for a number of different applications, and we are confident the results will provide a basis for fully sustainable electric drives.”

This study will run in parallel to Bentley’s OCTOPUS research programme, which aims to deliver a breakthrough in e-axle electric powertrains, utilising a fully integrated, free from rare-earth magnet e-axle that supports electric vehicle architectures.

As with OCTOPUS, RaRE is an OZEV funded project delivered in partnership with Innovate UK, which brings together the following partners with distinct roles and responsibilities. Bentley Motors will lead specification setting and test protocol development and support the design and manufacturing activities, while Hypromag will scale up the recycling processes developed at the University of Birmingham and convert the extracted powders to sintered magnets with properties designed around those required for the auxiliary motors. On its part, Unipart Powertrain Applications Ltd will lead the development of manufacturing scale-up routes to ensure facilities and processes defined are suitable for volume automotive manufacture.

Advanced Electric Machines Research Ltd will lead the motors’ design and development, while Intelligent Lifecycle Solutions Ltd will pre-process computer hard disk drives to remove the rare earth magnet containing components from the waste, which will be shipped to Hypromag for removal of the rare earth magnets. The University of Birmingham will provide cast alloys, which will be fed into Hypromag to blend with secondary materials to produce sintered magnets. (MT)

Mumbai-based automotive major Mahindra & Mahindra has announced its wholesales for April 2025 at 84,170 vehicles, a growth of 19 percent, including exports.

The auto major sold a total of 52,330 SUVs in the domestic market, which was 28 percent higher than 41,008 SUVs sold for the same period last year. Commercial vehicle sales in the domestic market came at 22,989 units, which was 4 percent YoY. 

Veejay Nakra, President, Automotive Division, Mahindra & Mahindra, said, “Building on the strong momentum of last year's performance, we began the year on a strong note in April by achieving SUV sales of 52,330 units, a growth of 28 percent and total vehicle sales of 84,170 units, a 19 percent growth over the same month last year. These numbers indicate the strength of our portfolio and customer offerings.”

JSW MG Motor India, a leading passenger vehicles manufacturer, has announced its wholesales for April 2025.

The company reported sales of 5,829 units, which was 23 percent higher over April 2024, when it sold 4,725 vehicles.

Interestingly, the automaker's popular offering, the Windsor EV, has continued to be the top-selling electric passenger vehicle for the seventh month in a row.

JSW MG Motor India's Windsor EV has now gone home to over 20,000 customers.

Maruti Suzuki India, the country’s largest carmaker, has reported its wholesales of 179,791 units in April 2025, marking a 7 percent increase compared to 168,089 units sold in April 2024. The growth was primarily propelled by strong performance in utility vehicles and a sharp rise in export volumes.

Domestic sales, including passenger and light commercial vehicles, remained flat with 142,053 units, as compared to 140,448 units in April 2024. Within this, light commercial vehicles (LCVs) like the Super Carry saw a significant jump of 34.2 percent, with sales rising to 3,349 units from 2,496 units last year.

In the passenger vehicle segment, SUVs such as the Brezza, Ertiga, Grand Vitara and others recorded a 4.4 percent increase, selling 59,022 units compared to 56,553 in the previous year. However, sales for Eeco declined by 5.2 percent, while the mini segment (Alto, S-Presso) saw a sharp 45 percent drop, falling to 6,332 units from 11,519 units. The compact segment, which includes high-volume models like the Baleno and Swift, grew by 8.1 percent, reaching 61,591 units.

Sales to Toyota Kirloskar Motor rose sharply by 79.2 percent, from 5,481 units to 9,827 units, indicating a growing demand for cross-badged products.

The standout performer was the export segment, which surged 26 percent to 27,911 units from 22,160 units in April 2024. This strong export growth helped bolster the company’s overall numbers despite weaknesses in domestic sub-segments.

While some product lines such as the mid-size sedan Ciaz (-63 percent) continue to struggle.

Tata Motors reported total wholesales of 72,753 units for April 2025, reflecting a 6 percent year-on-year decline from 77,521 units in April 2024.

The passenger vehicle (PV) segment, including electric vehicles, accounted for 45,532 units, down 5 percent from 47,983 units in the same month last year. Within this, domestic PV sales dropped 6 percent to 45,199 units, while international business (IB) sales rose significantly to 333 units, up from 100 units. Electric vehicle sales (domestic + IB) declined 16 percent year-on-year to 5,318 units.

Commercial vehicle (CV) sales stood at 27,221 units, marking an 8 percent YoY drop from 29,538 units in April 2024. Domestic CV sales contracted 10 percent to 25,764 units, while CV exports (IB) grew 43 percent to 1,457 units. Key sub-segments like Small Commercial Vehicles (SCV) and pickups saw a steep 23 percent decline.

Despite growth in certain categories like ILMCV trucks and passenger carriers, overall sales momentum was tempered across both PV and CV segments.