The R53 MINI Cooper S emits a lovely supercharged whine as it accelerates through the gears. In the Playmini Cooper S Extreme, that whine is even more vocal and underpinned by the baritone roar of its bespoke sports exhaust. Charging up the road, it also becomes obvious that the two-pronged attack of pumping engine power and reducing weight has resulted in a MINI on steroids that punches well beyond its class.
With 265 hp and around 200 pounds removed by the time the car hit the scales, the gap between hitting the throttle and being hit by torque in the small of the back has been shaved to virtually nothing. While pickup from idle is enhanced, though, the fully balanced engine really thrives on life in the upper half of the tachometer. Care is needed not to blow straight through speed limits on public roads.
In intermediate gears, light pressure on the throttle sends the speedo needle rushing round the dial. Even going from 70 to 100 mph in fifth is too easy. The solution is to take the Cooper S Extreme to where it was originally designed to spend a lot of its time: the track.
How do you go about building the most extreme supercharged street-legal MINI that can double as a serious track-day car? That was the question Playmini boss Nick Paddy and his purchasing manager, Andy Gamble, debated at the start of this project. Once they had a general concept, the next step was to find a donor car. Since they were going to gut it, an accident-damaged but easily repairable Cooper S was the cheapest option.
A few weeks later, a candy blue-and-white Cooper S that had suffered a light frontal impact arrived on a trailer and work began. The car was stripped completely back to a bare shell and sent off to the body shop for minor repairs. During body prep, any excess parts and related wiring-like air conditioning, airbag controls, radio, speakers, rear wiper and so on-were removed. As on the factory JCW GP, the Playmini car uses halogen lights, saving 15 pounds over the xenon units.
In the meantime, carbon-fiber doors, hood and rear hatch arrived from the Far East, joining the body for a coat of lurid Lamborghini Murciélago orange. The roll cage and the rest of the interior was painted Audi metallic grey to match the roof's exterior.
The cabin is racecar minimalist. A few gauges, carbon-fiber Corbeau seats, Willans racing harnesses, a Momo steering wheel and that's about it. Everything not trimmed in carbon fiber or Alcantara is painted to exterior panel standards.
Carbon fiber doors alone mean a significant weight reduction. While these do not offer the side impact protection of steel doors, the stout welded-in competition roll cage with its lateral crossbars more than makes up for it. Although the roll cage stiffens the shell by up to 30 percent, rigidity is further improved with an OMP lower chassis brace and a carbon fiber front strut tower brace.
Apart from the front bumper, the body kit is JCW, but Playmini uses real carbon fiber inserts at the rear to match the fronts. The Playmini hood scoop was color coded to match the bodywork. This hot-selling item reduces intake charge temperature by 46 degrees Fahrenheit at 90 mph.
The original supercharged motor had been damaged in the crash, so Playmini sourced a brand-new engine and set about preparing it for life beyond 250 hp. Although new, the engine was stripped down and checked for any weaknesses, then re-assembled with a Playmini big-valve head and Kent's high-lift camshaft. A smaller pulley was fitted to raise supercharger speed and boost.
The key to power in a Cooper S lies in keeping charge air temperature low. This responsibility falls to the highly rated Forge intercooler unit, backed up by a CO2 spray system. Downstream of this, a modified inlet manifold with a larger throttle body was fitted. The standard air filter box intake is in a null pressure zone, replaced here with a Dinan induction kit drawing cool air from behind the scuttle.
On the exhaust side, the Playmini four-branch exhaust manifold with a free-flow 200-cell sports catalytic converter was heat-wrapped to lower under-hood temperatures. This is mated to Playmini's production stainless steel sports exhaust, in this instance fitted with one-off titanium end pipes.
Other modifications include the oil cooler kit, Lumenition silicone plug leads, silicone water and air hoses. The ECU was remapped for the exact engine spec and a gratifying 265 hp was seen on the dyno. This is sent to a Quaife straight-cut, close-ratio gearbox with a limited-slip differential via a Helix fast road clutch.
To ensure that power can be deployed on the track, Bilstein coilovers-adjustable for bounce, rebound and height-were fitted and matched to Eibach anti-roll bars. Adjustable alloy rear control arms replaced the factory pressed-steel items and uprated anti-roll bar drop links went on. Upgraded bushings for the suspension, engine and transmission mounts came from Powerflex.
Finding the right alloy wheels in terms of size and offset was a challenge, but Revolution came up with a set of 7.5x17 lightweight motorsport-grade alloys. These are available in different offsets for the MINI, so it was just a matter of measuring to ensure they cleared the brakes without spacers.
The big stoppers behind the Revolutions consist of KAD's six-piston alloy calipers with Ferodo DS2500 pads and 330mm AP Racing grooved front discs. Since there is minimal weight at the rear, the stock calipers are used with EBC grooved discs and matching pads. Goodrich braided steel hoses and DOT 5 fluid round out the brake upgrade.