Automakers have known for a while that the future of high performance is electric. Hybrid supercars like the McLaren P1 and LaFerrari showed the way half a decade ago, and the pace of electrification has only increased since then. Porsche is just now bringing its all-electric Taycan to market to rave reviews while offering hybrid performance in the Panamera and Cayenne. A hybrid 911 is expected to follow, but hasn’t hit the market just yet.
A new venture from Elephant Racing is stepping into that gap with an innovative solution. Elephant has been around since 2002 making well-respected high performance suspension components for Porsches, but now the company is taking a giant leap into the unknown by producing the first-ever aftermarket hybrid system for Porsche’s legendary 911 sports coupe. They’ve created a new company to market the system, known as the Vonnen Shadow Drive.
“We’re all car guys, so it’s exciting to be part of this,” said Vonnen chief executive officer Chuck Moreland. “The Vonnen name comes from a mythical Viking ship. It was the first to have both oars and sails.”
When a car is described as a hybrid, we usually think about something like a Prius, where the car can run entirely on electric power for short distances. The McLaren P1 hybrid does that, but the Vonnen system is implemented more like the Ferrari, in which the electric motor simply adds power to the combustion engine’s output.
In technical terms, the Vonnen Shadow Drive is a “mild hybrid” system. That means the electric motor coexists with the original gasoline engine and kicks in when you need it to add extra power. The gas engine never stops working, and it’s still the primary source of power. Many automakers have used similar power-boosting electric motors, from the Mercedes-Benz CLS with EQ Boost to the Ram 1500 pickup truck with eTorque.
“We’re in the final stages of our development cycle,” Moreland told Digital Trends. “We’ve built two cars so far. The first was an initial prototype, which was technically a different design, but we learned a lot from it. We went back to the drawing board to develop this system that we’re currently offering. We’re doing a final redesign of the motor to enhance its thermal capabilities. We’ll have that available about four weeks from now, and we’ll be ready to do installations at that time.”
The first iteration of the Vonnen system will be available for retrofit onto Porsche 991 and 981 series vehicles. In practical terms, that means 2012-2019 911 models, including turbos, two-wheel-drive and four-wheel-drive models, and the GT3 performance model. The 981 series includes the Boxster and Cayman models from 2012-2016.
“One of the nice things about the way we integrated the drivetrain is that it fits in all these platforms,” Moreland said. “It doesn’t matter if it’s a mid-engine or rear-engine, or two-wheel-drive or four-wheel-drive. Our solution will go into all of those.”
Vonnen is also working on an air-cooled solution as well for Porsche 911 variants all the way back to 1965.
“We’re seeing a tremendous amount of interest from the guys with the older air-cooled cars,” Moreland revealed. “They’re interested in having modern power levels. By this time next year, we expect that to be moving out the door.”
The Vonnen system is ingeniously simple. The system is composed of an electric motor that replaces the original flywheel and starter motor assembly, as well as a battery, a cooling system, and a controller that’s smaller than a box of Kleenex.
The whole system is controlled through an app on your phone. The app shows the state of charge, amount of power being delivered, and allows you to select among various system modes, or turn it completely off.
The Vonnen electric motor becomes the starter for the gas engine as well as the power booster. Because it simply replaces the existing flywheel assembly, the system works equally well with both manual transmission and Porsche’s PDK twin-clutch transmissions.
“We’re taking advantage of all the gear reduction and torque multiplication in the transmission and final drive,” Moreland stated.
Another benefit to being external to the engine and driveline is that the Vonnen system requires no updates to the Porsche engine management system. The car doesn’t even know the hybrid system is there.
“That’s where the Shadow Drive name came from,” Moreland said. “It’s the idea that this is almost like a shadow drivetrain that is waiting in the background and not interfering with normal operation, but when you want the extra power it’s ready to go.”
“We don’t alter the performance behavior of the existing engine,” explained Bill Davis, vice president of engineering at Vonnen. “If you didn’t tell someone it was installed in the car and you left it turned off, it would be the same car you’ve always known. But when you turn it on, the car gets faster. You get that rush of torque.”
Each battery cell in the Vonnen system is about the size of a motorcycle battery. The battery array weighs about 85 pounds. It’s a high-output EV array with just 1 Kilowatt-hour of capacity.
“We want the highest possible power at the lowest possible weight,” Davis stated. “We didn’t want to change the character of the car by adding hundreds of pounds of batteries. If you think of it like a gas engine, we don’t have a big fuel tank, but the fuel pump is huge.”
The Vonnen system recharges itself by spinning the electric motor as a generator when you’re decelerating or sitting at a light.
“If you’re not asking for power, there’s surplus power available from the engine,” Davis said. “As a performance hybrid, it dovetails with the use case. We’re not trying to propel the car on a continuous basis. We’re looking for bursts of acceleration. To move the car at a steady rate, we just use the gasoline engine.”
The Porsche 911 is already a potent performance car, so we started our test drive with the Shadow Drive system turned completely off. The test vehicle was a stock 2013 991 Carrera equipped with a PDK transmission, and we left it in automatic mode.
After getting the baseline, we activated the system in Street mode. In this case, the Vonnen system offers some torque assist across a wide band of engine operation. The 991 became substantially more powerful in the low-midrange, and we could watch on our phone as the system added power and recharged itself.
“It’s amazing how much change you can feel by adding 100 foot-pounds of torque down low in the RPM range,” Davis said.
Once out of town, we placed the Shadow Drive in Sport mode. In this mode, power is biased to the midrange and higher. Sport mode is what you want for excellent acceleration out of corners when the car is already moving at speed.
“Most of the driving you do, it’s going to be in Street or Sport mode,” Davis agreed. “Our peak performance is dialed back a bit, and we use different throttle mapping. It just makes the car feel much more lively.”
For a final test, we placed the 991 on a flat, straight stretch of pavement and turned the Vonnen system off. The 3.4-liter engine in the 991 is rated at 345 horsepower and 288 pound-feet of torque, but its takeoff can be a bit leisurely. That changed dramatically when we put the Shadow Drive system into Overboost mode.
“In our top mode, called Overboost, we’re adding 150 foot-pounds of torque and 150 horsepower,” Davis said. “It’s all about taking advantage of the thermal capacity of the motor. Depending on how warm the motor is when you start using Overboost, it’s about 10 seconds of maximum boost, then it cools off and you can go again.”
With Overboost enabled the Porsche leapt ahead from a stop and made it to 60 in about 3 seconds. Suddenly the 10-second limit in Overboost mode seemed like plenty of time. You could use Overboost mode to surprise supercharged and nitrous-equipped cars at the drag strip, if you’re into that sort of thing.
For everyday driving, you can put the Vonnen system into street mode and enjoy a well-balanced performance upgrade. The electric motor delivers its power at the moment you tip into throttle, and the effect is quickly addictive.
To get the Vonnen Shadow Drive, you first need a compatible Porsche. Then you can take it to Vonnen in Santa Clara, California and they’ll install the whole system for $75,000.
“One business model is direct to the customer, where they have the car and they bring it to us and we do the change,” Moreland said. “The other is through tuner shops, which are independent companies that build cars for their customers.”
With the Taycan arriving in dealerships, and the Cayenne and Panamera hybrids raising the performance level in the four-door Porsche world, an aftermarket mild hybrid system that costs about as much as a well-kept 991 might seem like a stretch. However, Moreland and the Vonnen team point out that they’re aiming at a completely different buyer.
“What we offer is the classic driving experience with engaging engine sounds and RPM,” Moreland contended, “and a manual transmission if you have that. We just supplement that with additional power.”
The truly disruptive benefit of the Vonnen system is that a similar system could potentially be installed on any modern computer-controlled vehicle. The performance benefits of mild hybrid electrification could be applied to the sports car of your choice. That means not only is the future electric, but potentially the past as well.
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