Audi is taking aim at the new Porsche Boxster and upcoming second-generation Porsche Cayman with a spectacular 174mph version of the Audi TT RS, seen at the Geneva motor show for the first time.
Called the Audi TT RS plus, the powered up coupe and roadster pairing joined a formidable display of new Audi models which includes the third-gen Audi A3 and Audi RS4 Avant included.
The centrepiece of the new range-topping TT is a tuned version of Audi’s turbocharged 2.5-litre five-cylinder direct injection petrol engine – as used by the go-fast TT RS and RS3 Sportback.
Mounted transversely over the front wheels in a unique carbonfibre-trimmed engine bay, the four-valve-per-cylinder unit delivers an added 20bhp and 11lb ft of torque over the standard tune of the engine. Power is up to 355bhp and 343lb ft – some 44bhp and 78lb ft more than the new Boxster S’s naturally aspirated 3.4-litre horizontally opposed six-cylinder.
Among the changes brought to the compact powerplant - known internally as EA855 - is a revised inlet manifold and increased turbocharger boost pressure. Together, they provide the 1450kg TT RS plus coupe with a power-to-weight ratio of 244bhp per tonne, with the TT RS plus roadster coming in at 235bhp per tonne.
Engineers at Audi’s quattro division have also provided the TT RS plus with an exhaust system flap that opens on generous applications of the throttle for added aural effect.
Like the Audi TT RS, drive is channeled through a standard six-speed manual gearbox to all four wheels via a Haldex style multi-plate clutch. A seven-speed dual clutch S-tronic gearbox featuring a launch control function is available as an option.
With the system, the TT RS plus coupe will storm from standstill to 62mph in just 4.1sec, with the slightly heavier roadster taking 4.2sec. In manual form, they require an additional 0.2sec respectively, according to Ingolstadt’s official performance figures. Top speed in both cases is limited to 174mph – up by 19mph on the standard TT RS, which is limited to 155mph.
The gain in performance is achieved without any dramatic effect on consumption, which Audi puts at 33.2mpg for the coupe and 32.8mpg for the roadster. By comparison, the new mid-engined/rear-wheel drive Boxster S, which also makes its debut in Geneva, reaches 62mph in a claimed 5.0sec, tops out at 169mph and returns a combined 35.3mpg.
Allied to the TT RS plus’s engine upgrade is a revised version of the standard TT RS’s already firm-riding MacPherson strut (front) and multi-link (rear) chassis complete with sinister-looking, black and red 19-inch alloy wheels shod with 255/35 tyres.