Celebrating its 25th anniversary this year, the Ariel Atom has been around long enough that it’s possible to forget how awesome it is. Ariel is providing a reminder in the form of an even more extreme version, with more power than any Atom to date. It’s called the Atom 4RR.
Built to celebrate the Atom’s quarter century of existence, the 4RR is built around a heavily upgraded Honda K20C 2.0-liter turbo-four. It’s similar to the engine used in the current Civic Type R and Integra Type S, but here it makes 525 horsepower and 405 lb-ft of torque in the sportiest of three engine maps. Options for 500 hp/331 lb-ft and 400 hp/280 lb-ft are also available.
Ariel extracted that power by changing or upgrading almost everything. The 4RR-spec engine has closed-deck sleeves, Ariel-specific forged pistons and connecting rods, revised cylinder head and port geometry, alloy valves with upgraded springs and guides, new camshafts, a larger turbo that generates 1.7 bar of peak boost, and 1,400-cc fuel injectors to keep up with it. The engine inhales through a carbon fiber intake worthy of an F1 car, and exhales through a titanium exhaust system, while a gated oiling system and high-flow pump keep lubricant flowing under harsh track conditions.
Power is sent to the rear wheels through a Quaife six-speed sequential gearbox with pneumatic paddle shifters. The clutch is only needed for moving away from a stop, and there’s an auto-blip function for downshifts. That, and a curb weight of just 1,474 pounds, allows the 4RR to scoot from zero to 62 mph in 2.4 seconds and to 100 mph in 5.1 seconds, making it the quickest Atom production model yet, according to Ariel. Top speed is 175 mph.
The signature Atom exoskeletal chassis is sprung with adjustable twin-tube Öhlins dampers. Stopping is handled by AP Racing two-piece ventilated rotors clamped by four-piston calipers, with driver-selectable ABS with 11 settings (including “off”). The 12.2-inch rotors are the largest that can fit within the Atom’s staggered (16-inch front, 17-inch rear) wheels, which wear Yokohama A052 tires sized 195/50R16 in front and 255/40R17 in back.
Carbon-fiber side pods are based on the ones developed for the Atom 4R, but with additional cooling channels for the engine and gearbox. An enormous rear wing and other aero elements and mud guards (despite its track-focused nature, Ariel says the 4RR is still designed for road use) are made of carbon fiber as well. Neat 25th anniversary graphics provide the finishing touch.
In Ariel’s home market, the Atom 4RR retails for 208,000 British pounds. That’s about $280,000 at current exchange rates, assuming Ariel reserves any build slots for the U.S. Cars will be made to order “in extremely limited numbers,” according to the company, but hopefully there will be enough to go around.