The Ariel Atom 4RR is a street-legal go-kart with a power output of 525 horsepower.

      Ariel Motor Company

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      This year marks the 25th anniversary of the Ariel Atom, a car that has become so iconic that its greatness can be easily overlooked. To remind enthusiasts of its allure, Ariel has unveiled an even more extreme version—the Atom 4RR—boasting the highest power output of any Atom to date.

      Created to commemorate a quarter century of the Atom, the 4RR features a substantially upgraded Honda K20C 2.0-liter turbo-four engine. This engine, similar to that found in the latest Civic Type R and Integra Type S, produces 525 horsepower and 405 lb-ft of torque in its most aggressive engine map, with options for 500 hp/331 lb-ft and 400 hp/280 lb-ft as well.

      Ariel has increased the power output by modifying nearly every component. The engine in the 4RR is equipped with closed-deck sleeves, Ariel-specific forged pistons and connecting rods, a revised cylinder head and porting, alloy valves with enhanced springs and guides, new camshafts, and a larger turbo capable of delivering 1.7 bar of peak boost, along with 1,400-cc fuel injectors to match. The air intake system is crafted from carbon fiber to rival that of an F1 car, while the exhaust is made from titanium. Additionally, a gated oiling system and a high-flow pump ensure proper lubrication under demanding track conditions.

      Power is transmitted to the rear wheels via a Quaife six-speed sequential gearbox, complete with pneumatic paddle shifters. The clutch is only necessary for initial movement, and an auto-blip feature assists with downshifts. Combined with a lightweight curb weight of just 1,474 pounds, this allows the 4RR to accelerate from zero to 62 mph in 2.4 seconds, and to reach 100 mph in 5.1 seconds, making it the fastest Atom production model according to Ariel. The top speed is reported at 175 mph.

      The iconic exoskeletal chassis of the Atom is paired with adjustable twin-tube Öhlins dampers. For braking, it utilizes AP Racing two-piece ventilated rotors with four-piston calipers, accompanied by driver-selectable ABS with 11 settings (including an “off” option). The 12.2-inch rotors are the largest that can be accommodated by the Atom’s staggered wheels—16 inches in the front and 17 inches in the rear—fitted with Yokohama A052 tires sized 195/50R16 at the front and 255/40R17 at the back.

      The carbon-fiber side pods are redesigned from those of the Atom 4R, incorporating extra cooling channels for both the engine and gearbox. A large rear wing and various aerodynamic elements, including mud guards (though the 4RR is predominantly track-oriented, Ariel ensures it is still road-legal), are also constructed from carbon fiber. Distinctive 25th anniversary graphics complete the design.

      In Ariel's home market, the Atom 4RR is priced at 208,000 British pounds, translating to roughly $280,000 at current exchange rates, pending reservations for the U.S. market. Production will be limited, with cars made to order, according to the company, though they hope to meet demand adequately.

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