Stuttcars recently spoke with the minds at Vonnen to better understand the Shadow Drive, a modern solution to improving Porsche sports car performance. They approached the challenge by replacing the existing engine’s flywheel with a powerful electric motor. Hence, torque and power are added directly at the crankshaft; both gasoline and electric power work in harmony. The combined power is delivered through the existing transaxle and drive wheels and is available in every forward gear.
Why Not Just Build Up The Gasoline Engine? Vonnen-level power increases are nearly unheard of using traditional gasoline engine performance upgrades like exhaust, cams, intake, and displacement. Only turbos with large boost increases or nitrous can get there. And in all cases, the gasoline engine is seriously compromised in terms of drivability, smog, fuel mileage, noise level, octane requirements, reliability, and life expectancy. In contrast, Vonnen adds an incredible 150 ft/lbs at the crank. Smooth, quiet, clean, reliable, and instant response. The engine can remain completely stock. Or not.
Behind the scenes with Chuck Moreland, CEO and Founder of Vonnen / Elephant Racing
Stuttcars is honored to have had Chuck Moreland, founder of Vonnen, answer some of our questions:
Stuttcars: While it’s one thing to observe supercar manufacturers (including Porsche) embrace an axial-flux motor-based hybrid system, how did you know you and your small team could create your own version? It seems you would have needed direct experience in that field to pull off such a technically sophisticated product.
Chuck Moreland: Great question. While the technical details of the motor and battery system come first to mind, I think integrating it into the driving experience and packaging it into the car was at least as challenging. We were actually well positioned to pull this off, perhaps uniquely so for a company of our scale. Our team has an unusual mix of car-specific knowledge blended with technical expertise in the battery, motor, software, and system control elements.
Integrating a motor and battery into a drivetrain and chassis not designed for them requires intimate knowledge of the vehicle platform. That demands a solid understanding of both the chassis and the changes through all the generations we support. Originating as a spin-off from Elephant Racing, Vonnen has built on 24 years of experience designing suspension and chassis products for Porsche cars. We know the cars and chassis inside out.
On the motor/battery side, Bill Davis is our VP of Engineering and leads the Shadow Drive program. Bill has spent most of his career in the EV and hybrid space. Most recently, he held engineering roles at both Tesla and Wrightspeed, developing solutions for EV and hybrid products. Before that, Bill developed electric shuttle buses.
I’m a tech industry veteran with a background in electrical and software engineering. I spent a good chunk of my career engineering systems control products. Our mix of vehicle-specific experience, technical knowledge, and genuine enthusiasm for what we are doing gave us the edge to pull it together.
Stuttcars: As you know, the Porsche community is very opinionated about what is taboo or not regarding modifications. What has been your strategy to introduce such a non-traditional approach to performance enhancement to the California market and beyond
Chuck Moreland: Our strategy is grounded in respect for these truly iconic cars and the special driving experience they deliver. In stock form, they are incredibly engaging, with a visceral connection between man and machine that spans both the driving and the visual experience. Yet for all the engagement, many enthusiasts still want more power. That is especially true of the air-cooled cars that are incredibly fun to drive, but by modern standards are disappointingly slow.
Our strategy is to make the system invisible. Make it disappear into the chassis and disappear into the analog driving experience. Disappearing into the driving experience means that everything is exactly as before: same driver engagement, same exhaust note, same build of power with RPM, same clutch and shifter, same nimble lightweight handling.
The driving experience is unchanged because the engine and the driver’s direct control of the throttle remain the same. There is no EV mode. The always-running engine powers the car as normal. The electric motor assists the engine only when accelerating, smoothly feeding in torque based on throttle position. The result is a driving experience that is completely unchanged, just more powerful. We call this an analog hybrid system.
This is usable power that even the purist can enjoy. Unlike peaky race engines or turbo additions, the car’s character remains unchanged. The analog driving experience is enhanced by making it torquier throughout the RPM range. Invisibly. Disappearing into the chassis is a bit more literal. The motor is hidden inside the trans bellhousing, bolting in place of the flywheel. With the car up on a lift, it is difficult to find the system even from the underside.
The battery is integrated into the fuel tank, fitting within the tank’s original silhouette. Covered with carpet, the trunk appears normal, with storage capacity intact. The system’s weight also disappears because offsetting items come out of the car. The starter motor is no longer needed, so it is removed. The heavy 12v battery shrinks down to a lightweight unit, remaining only to support accessories. The flywheel is removed. Air-cooled cars have a net weight gain between 0 and 50 lbs. Driving dynamics and lightweight feel are unchanged.
Stuttcars: Does the Shadow drive need to be installed by Vonnen, or can customers have their own mechanics install it?
Chuck Moreland: Most customers send the car to us for installation at our Northern California facility. We also work with qualified shops local to the customer to facilitate installation in other US-based and worldwide locations.
Benefits of Vonnen
Electric motors behave differently than gasoline engines. Vonnen uses this to great advantage.
Torque From Idle
Vonnen’s electric motor delivers a full 150 ft/lbs of torque from idle to 5500 rpm, with 120 ft/lbs still available through to 7500 rpm. That means power at usable RPM, no need to downshift or wait for the engine to rev. Tip into the throttle at 1000, 2000, or 3000 rpm and go. It’s about having power when you need it, not just at some peak-power RPM. Large area under the torque curve makes Vonnen easy to drive fast. The gasoline engine behaves as normal, building power as RPM rises. Let the engine rev to its powerband, and the combined power output is stunning.
Instant Response
Immediate throttle response provides the driver with amazing power delivery control. This is especially useful when modulating the throttle to accelerate hard out of turns. Response happens within 25ms. Normally aspirated gasoline engines can’t even come close… and forget about turbo lag. This gives the driver an unrivaled sense of connection and control.
Power To Weight
Vonnen’s electric motor weighs in at a mere 38 lbs, yet can deliver bursts of 150 ft/lbs of torque. That’s 3.9ft/lbs per pound! Vonnen is engineered to match the way we drive performance and road racing cars; bursts of acceleration separated by longer periods of steady state, deceleration and light acceleration. Vonnen is optimized to match this driving profile perfectly, keeping weight to a minimum while delivering bursts of high power. Between bursts the system is cooled and recharged, ready for the next burst.
Smog Compliance
Clean performance. The gasoline engine operation is not altered, including all smog and emission control systems and operation. Smog test results are the same, with or without the Vonnen system installed.
Regenerative Braking
Vonnen’s motor can also operate in generator mode when not supplying boost. This allows the battery module to recharge from the gasoline engine and recaptures energy normally lost through braking as heat. Power used to turn the motor in generator mode slows the car, and is stored in the battery module – later used to accelerate the car. Recovering energy normally lost to braking enables Vonnen to increase the vehicle’s fuel mileage and efficiency. It is in effect “free” energy. The existing mechanical brakes and ABS system remain untouched and operate normally. Pad and rotor life are extended because they’re under less stress.
Fuel Economy
Energy normally lost to the brakes is stored and used for later acceleration, meaning less fuel is burned to get to where you’re going.
Software Controlled
Vonnen’s operation is controlled by the Vonnen Control Unit (VCU). Various modes of operation are driver-selectable, and the present modes of operation are the following:
- Street Mode: Optimized performance at street RPM range; drive torque used to accelerate only.
- Race Mode: Optimized for maximum performance at higher RPM; drive torque used to accelerate only.
- Stealth Mode: Optimized for silent bursts of performance, electric torque is used to accelerate while keeping the exhaust note discrete.
Off-Line
Vonnen system maintains charge levels, but does not create drive torque or any drag on the drivetrain.
Easily Upgradeable
System software is upgradeable. As we develop enhancements to modes of operation, new modes, or other feature enhancements your system can be upgraded remotely. Together with your smart phone, the VCU software can be updated wirelessly.
Seamless Integration
Vonnen eBoost for Porsche. The Vonnen system is a transparent overlay on the existing drivetrain and does not alter its behavior with respect to smog and emissions. Exhaust systems, including catalytic converters, are not altered. All existing emission control equipment remains intact, functional, and unaltered. The vehicle’s stock ECU is not altered, reprogrammed, or interfered with in any manner. Smog test results are the same, with or without the Vonnen system installed.
