There is a regulation of the German Motor Sport Federation (ADAC) which dictates that rally cars must be audible and not even the fact that it is the first car of its kind 100% electric exempted the Opel Corsa-e Rally of having to comply with it.
Since until now no one had tried to solve this “problem”, Opel engineers put “hands on” to create a sound system so that the Corsa-e Rally could be heard.
Although electric road vehicles already have sound systems to warn pedestrians of their presence, creating a system to be used in a rally car was more complex than one might think.
The challenges
The main “problem” encountered by Opel engineers was finding hardware with the necessary power and robustness.
The loudspeakers are normally installed inside the car and are therefore not particularly resistant or waterproof, which is crucial when you take into account that in Corsa-e Rally they have to be installed outside the car and exposed to the elements and abuse. of the competition.
The solution found
The solution was to use speakers identical to those used in… ships. In this way, the Corsa-e Rally has two waterproof loudspeakers, each with 400 Watt of maximum output power, installed at the back, in the underside of the car.
The sound is generated by an amplifier that receives the signals from a control unit, with specific software, which makes it possible to adapt the sound according to the rotations. The result of work over several months, the software made it possible to create a stationary “idle sound” adaptable to all speed and regime ranges.
Here are the speakers installed on the Opel Corsa-e Rally.
As you would expect, the volume can be adjusted, with two levels: one for use on the public road (the silent mode) and another for use in competition (when the volume is turned up to maximum) — in the end, it continues to sound like a… spaceship.
The debut of this unprecedented system in competition is scheduled for the 7th and 8th of May, the date on which the Sulingen Rally takes place, the first race of the ADAC Opel e-Rally Cup.