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VONNEN: Porsche Shadow Drive Performance Hybrid System

The car you love with amplified performance

Key People
Chuck Moreland and Bill Davis
What Is It
Shadow Drive. A first-of-its kind performance hybrid retrofit system
2009+ Porsche 911s & Boxster/Caymans
~ $75,000
More Information

Porsche Shadow Drive Performance Hybrid System

Welcome to our first “Porsche Ecosystem” provider deep dive. This is a new initiative where we highlight the brands and businesses supporting the broader Porsche community with products and services. It may be a local restoration shop or national brand selling Porsche parts or a niche supplier of Porsche services. We decided to start this initiative because we get tons of feedback from members who want to know where they should shop for their Porsche and asking us questions on how to solve specific problems. This is our way of introducing Porsche owners to the companies that can help them.


Our first deep dive is going to be a fairly new and super interesting player in the Porsche aftermarket performance space. The company is VONNEN and they have developed Shadow Drive, a first-of-its kind performance hybrid retrofit system. It really is a ground-up rethink of what it meant to integrate substantial power gains to modern and classic cars alike. Performance Hybrid retrofit is a new category and the concept promises strong performance gains while preserving the “scream of the engine on-cam”. By mounting a thin electric motor/generator where the flywheel goes, plus a small battery, cooling system, and inverter, their ‘Shadow Drive’ adds a silent +150 Horsepower and Torque to any 2009+ Porsche sports car, from idle, without touching the engine, powertrain, or stock ECU in any way.

© Vonnen

VONNEN is a company from the owners of the well-regarded Elephant Racing. What is unique about the VONNEN offering is that its the first kind of tuning package in which you don’t touch the engine at all. By replacing the flywheel with an electric motor/generator, placing a battery pack and cooling under the front trunk, and operating on a standalone ECU, VONNEN is able to add horsepower and torque without touching the engine at all, basically delivering hybrid tech for cars that were never designed to be hybrid, and here’s the craziest part: It works way better than you think it ever could.

Instantly, that motor kicks in, boosting the native engine’s horsepower and torque by roughly 50 percent and giving me an idea of how Popeye feels after gulping spinach. – Wired

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VONNEN Shadow Drive

The core of Shadow Drive is the liquid-cooled VONNEN Shadow Drive™ motor, which sits between the engine and the transaxle, delivering a serious punch of additional torque from idle through redline. The patent pending technology in Shadow Drive allows a slim-profile electric motor to take the place of the factory flywheel. With Shadow Drive, the original car is maintained. The driving experience, sound, weight, balance, history and heritage all remain in the foreground. The modern technology and instant delivery and torque are waiting and ready to go.

Shadow Drive Vonnen
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So, what is included in the Shadow Drive:

  • Motor/Generator replaces the stock flywheel. Effectively becomes an electric flywheel positioned inside the existing bell housing. This patent-pending approach creates great portability to different drivetrains and chassis.
  • Extremely power-dense battery. Enables compact size and lightweight for ease of concealment and low impact to handling dynamics.
  • Shadow Drive control system. Monitors and reacts to, but does not change, existing engine operation. Existing engine ECU is unchanged, unaware and unaffected by the presence of the Shadow Drive overlay.
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The Shadow Drive is configurable with up to 150 hp and 150 lb-ft of assistance. This is managed through a proprietary smartphone app. Shadow Drive begins making power at idle continuing through redline. It is the most significant way to add power in the desirable “area under the curve” of a car’s performance envelope. In terms of feel, it’s seamless with no clear on/off boost sensation. Shadow Drive delivers instant throttle response with a wave of horsepower and torque from idle to redline.

In this 991 Carrera there’s still all the engagement and aural appeal, only with the electrical motor giving a useful additional shove into the drivetrain. – Top Gear

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Interestingly, Shadow Drive layers with traditional mechanical performance modifications regardless of engine power output. It provides power assistance inverse to the engine’s power curve so that boost is most significant where the internal combustion engine has lower torque. In practical terms, what this means is that it torque fills on engines with big, laggy turbos or aggressive cam profiles. It augments power as the turbos spool or the engine comes on cam.

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Power is available in bursts via normal application of the throttle. Boost is mapped to throttle position to deliver more electric assistance at higher throttle positions. The battery is replenished during normal driving through regenerative brake recharge. Drive modes are user selectable via the smartphone app.

The Cost

Shadow Drive is $75,000 installed at Vonnen in Santa Clara (there is also a global network of partners who can help if you aren’t local). Not cheap by any means, but this new technology is certainly an interesting option for those looking to keep the characteristics we love about flat-6 engines with a serious bump in performance.


2012-2019 Porsche 911s (991 series), as well as the same generation Cayman and Boxster (981 series). 997, 996 and air-cooled 911 as well as older generation Boxster and Cayman applications also in development. The system works on manual or PDK transmissions and it works on both naturally aspirated or forced induction engines.

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Such a clever system with really innovative engineering. The price will come down and one day it might be as affordable as doing a turbo conversion on your car. Really interesting. Overall, we love what Vonnen has done here; I think they have singlehandedly shown the direction for the medium-term future of car modifications, and done it with an incredibly high-quality system. The price being high is just what it costs to do what they’ve done; really impressed.

Reviews of the Shadow Drive Porsche System