New Porsche 911 Carrera 4 Offers Electronically-Controlled

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In the new generation 911 Carrera 4 and Carrera 4S, the all-wheeldrive is now provided via electronically-controlled PorscheTraction Management (PTM), which replaces the former all-wheeldrive with its viscous multiple-plate clutch. The superior PTMsystem was first developed for the 911 Turbo and has been modifiedfor the Carrera models. The transmission delivers an even higherlevel of driving stability, traction and agility, further enhancedby the mechanical limited slip differential now fitted as standardto the rear axle.

PTM feeds exactly the right amount of engine torque in eachsituation through an electronically-controlled multiple-plateclutch to the front wheels, supplementing the flow of power to therear wheels. Combined with the highly dynamic PTM control system,this clutch precisely delivers a distribution of power and torqueto the front and rear axles as road and driving conditions change.With the previous viscous clutch, up to 40 per cent of torque couldbe directed to the front axle. The new electronically-controlledPTM system delivers an infinitely variable torque split, and isable to distribute up to 100 per cent of traction to the front orrear wheels.

PTM provides a faster and more precise transmission of power in alldriving situations, and this offers not only excellent stability athigh speeds, but also increases further the level of responsivenessof the car to the driver.

New engines with Direct Fuel Injection (DFI)
The 911 Carrera 4 models share their all-new flat-six engines withDirect Fuel Injection (DFI) with the two-wheel drive Carrera 2 andCarrera 2S. The features and characteristics of the new enginesspeak for themselves. Depending on the model, the all-wheel-drive911 Carrera offers up to 8.5 per cent more power, fuel economyimproved by up to 12.9 per cent, and 15.4 per cent lower CO2emissions than the previous generation. Specifically, output of the3.6-litre power unit is up by 20bhp to 345 bhp (254 kW). At thesame time, a Carrera 4 Coupé with PDK transmission, to take justone example, offers fuel consumption of 28.0mpg (10.1 l/100 km).

The improvements on the 911 Carrera 4S with its 3.8-litre powerunit are equally significant, with maximum output up by 30bhp to385 bhp (283 kW) and overall fuel consumption down in the case ofthe Carrera 4S Cabriolet with PDK to 26.4mpg (10.7 litres/100 km).

The driver benefits from a further advantage of direct injectionevery time he touches the throttle pedal: with fuel being injectedfractions of a second prior to combustion, the engines respond moredirectly and spontaneously to even the slightest movement of thedriver