US company turns Porsche 911s into hybrids

A California-based company called Vonnen showcased some rather interesting technology at the Porsche Rennsport Reunion this weekend, a hybrid system for the Porsche 911 which replaces the flywheel with an electric motor.

First brought to public attention by car culture website Jalopnik, the system sits in place of the original flywheel, with a battery in the front storage compartment of the car with a control unit, as well as an energy inverter mounted at the rear ‘parcel shelf’.

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Essentially, the ‘flywheel’ motor allows an extra boost of power through the drivetrain without interrupting the power provided by the engine.

“This is the best of your Porsche, made better,” Vonnen says of its upgrade.

“You keep the sound, the experience, the feel, smells and sensations of your high performance gasoline engine and you get a tremendous power increase with amazing throttle response and torque from idle.”

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Vonnen says the motor adds an additional 130kW to the performance of a standard 911, or 261kW in ‘stage 2’ form. It’s important to note that this power is a temporary boost, which then takes some time to recharge and cool.

The claimed performance increase means the 0-60mph (0-97km/h) sprint is dropped dramatically to 3.0 seconds (stage 1) or 2.6 seconds (stage 2) for a 2012 991 911 Carrera.

In addition, a RennList Porsche forum member says they spoke to a Vonnen representative, and was told the modification works for both manual and PDK models.

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Vonnen says the ‘motor generator unit’ (MGU) doesn’t interact with any aspects of the vehicle outside of the drivetrain, meaning brakes, suspension, and other aspects of the 911 remain stock.

In addition, the MGU adds only 55kg (stage 1) to 86kg (stage 2), no more than a passenger.

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“The existing mechanical brakes and ABS system remain untouched and operate normally. Pad and rotor life are extended due to less demand being placed upon them.”

The Vonnen MGU also becomes a starter motor for the car, which means the original one is removed.

The system starts from USD$75,000 (AUD$104,000), which becomes an expensive exercise on an already expensive car.