Water Music

The wheels lose their grip and the driver becomes a passenger—hydroplaning can be sudden and treacherous. In the new Porsche 911, Wet Mode ensures improved driving safety. How does this worldwide innovation work?


“Purple Rain” by Prince, “Rain Fall Down” by the Rolling Stones, “Here Comes the Rain Again” by the Eurythmics—there are dozens of international hits featuring rain and rhythms imitating the patter, whoosh, or beat of rain. For drivers, the sounds of rain are more warning signal than inspiration, because heavy rains and wet roads always mean the risk of slipping or even hydroplaning. Porsche engineers have now developed an assistance system to significantly reduce this hazard: Wet Mode.

This new technology harnesses the sound of water. Acoustic sensors in the front wheelhouses are on constant lookout for stirred-up water and recognize when the road is dangerously wet. Sand, dirt, and pebbles that could also trigger the system are ignored, because they have a different frequency pattern. Once a critical quantity of water is detected, Porsche Stability Management (PSM) and Porsche Traction Management (PTM) switch to a higher level of sensitivity and prepare to give an instant response. What’s more, the system could one day transmit a wet-road warning via an online connection to other cars in the vicinity with the corresponding interface. This too could reduce the risk of accidents in wet road conditions.

Acoustic sensors
In the front wheelhouses, sensors register how much water is being swirled up.

Cockpit display
When the road is wet, the driver is advised to activate Wet Mode.

A display in the 911 cockpit advises the driver to switch on Wet Mode. It’s simple to do so, either at the touch of a button on the center console or directly using the steering wheel’s mode button. When Wet Mode is activated, the system influences a number of parameters, always with the goal of maximum driving safety. The most important element is the drive unit, consisting of the engine and the transmission. Wet Mode keeps revs low by means of early upshifting.

The engine reacts more reticently to commands from the gas pedal. Traction-slip control behaves more sensitively than at other times, as do the antilock brakes and the curve-braking module. In the case of models with all-wheel drive, the force distribution is shifted more to the front axle; this prevents oversteering and sudden swerving at the rear. Active aerodynamics open the front air flaps and extend the rear spoiler completely. This pushes the sports car even more firmly into the road.

Stronger, wider, faster. Porsche celebrates the eighth generation of the 911. Wet Mode makes sure that the 911 continues to advance in the area of driving safety as well. Sensors that listen to the sounds of the road can even make driving in the rain a pleasure. Perhaps to the strains of Handel’s Water Music or the Beatles’ “Rain,” whose lyrics include “Rain, I don't mind.” Indeed.

Air flaps
When Wet Mode is activated, the air flaps open. This increases driving stability.

Rear spoiler
When Wet Mode is activated, the spoiler is fully extended. The downforce increases.

Sven Freese
Sven Freese