MINI has unveiled the new John Cooper Works versions of the F54 Clubman and F60 Countryman, which now come with a lot more performance than their respective predecessors. In fact, MINI says these new JCW cars are “by some measure the most powerful models in the brand’s sixty year history.”

Under the bonnet of both models, there’s a 2.0 litre turbocharged four-cylinder that comes with a few enhancements over the unit used in the standard Cooper S Clubman and Countryman. For instance, there’s a reinforced crankshaft, a main bearing with an extended cross-section, specific pistons and connecting rods, redeveloped air intake duct, as well as a new vibration damper. Essentially, it’s the same B48 engine you’ll find in the BMW X2 M35i.

MINI has also introduced a new exhaust system “with remarkable sound development” and tacked on a petrol particulate filter to ensure compliance with the Euro 6d-TEMP standard. More importantly, a bigger turbocharger has also been fitted, and sees a lower compression ratio (9.5 from 10.2).

What you end up with is an engine that churns out 306 PS (302 hp) between 5,000 and 6,250 rpm and 450 Nm of torque between 1,750 and 4,500 rpm, which represents an improvement of 75 PS (74 hp) and 100 Nm over the previous JCW power unit used in both cars.

As a result, the new JCW Clubman takes just 4.9 seconds to complete the zero to 100 km/h sprint (previously 6.3 seconds), while the JCW Countryman takes 5.1 seconds (previously 6.6 seconds). The electronically limited top speed of 250 km/h is shared.

To ensure these improvements are met with proper temperature management, the cars come with two external radiators, a larger-volume expansion tank, an independent cooling module mounting, an electric ventilator with increased output, and a third cooling level via a condenser.

There’s even a dedicated external transmission oil cooler for the eight-speed Steptronic automatic transmission, which is now the only gearbox available for these JCW models – the previously available six-speed manual has been omitted (boo). A mechanical differential lock at the front axle and an ALL4 all-wheel drive system complement the auto box.

Efforts have also been made to optimise the performance-tuned chassis, which now boast new swivel bearings for improved camber values on the front wheels. Meanwhile, specific rear-axle kinematics improve the potential for transmitting lateral guide forces when cornering.

An adaptive chassis is the upgrade from the standard sport chassis, with both being 10 mm lower than non-JCW versions. The brake system hasn’t been left out either, with the front now packing 360 mm discs and four-piston calipers finished in red, while the rear sees 330 mm discs.

Styling-wise, there’s not a whole lot new on the outside, as both cars look nearly identical as before. Notable revisions can be seen on the JCW Clubman, which gets new LED taillights following a Union Jack design like the rest of the facelifted Clubman range.

On the equipment side of things, both JCW models here come with 18-inch John Cooper Works light metal wheels in Black Grip Spoke design by default, with the option of other designs in 18 and 19 inch sizes.

You also get LED headlights that now feature a Matrix high beam function, Radio MINI Visual Boost with Connected/Connected Navigation and a 6.5-inch touchscreen (upgradeable to an 8.8-inch unit with Connected Navigation Plus), sport seats and steering wheel, a new gear lever and anthracite headliner.

New F54 MINI John Cooper Works Clubman

New F60 MINI John Cooper Works Countryman