Ask driver Patrick Long, and he'll tell you he's "still pretty charged up (forgive the pun)" after returning to the States following two weeks of testing the car on the Lausitzring circuit outside Berlin.
We had a chance to chat with Long next to one of the world's only two 911 GT3 R Hybrid models, incongruously parked outside a swanky restaurant in midtown Manhattan.
He was there to announce that the groundbreaking hybrid would make its first appearance in U.S. competition in the Petit Le Mans race, the last event of this year's American Le Mans Series, to be held October 3 at the Road Atlanta racetrack.
Compared to the RSR, he said, he could brake later into turns and accelerate earlier, knowing he had up to 160 horsepower available to power the front wheels for added thrust out of corners.
The R Hybrid provides that front-wheel power for 5 to 7 seconds after the driver initiates it via a small gold paddle behind the steering wheel.
A row of LEDs shows the driver its state of charge at any given point; once the driver triggers it, Hybrid Manager software determines how much torque can be delivered to the front wheels, based on speed, steering angle, cornering force, wheel slip, and a host of other sensor data.
That power is generated by energy stored in the form of a flywheel rotating at high speed inside in the Kinetic Energy Recovery System, or KERS.
The drum-shaped unit sits on the passenger-side floor of the racer, along with its power electronics, orange high-voltage cables, and pipes carrying an oil-based coolant to and from side radiators behind vents just behind the doors.
When the driver asks for power, a clutch connects the flywheel to a motor-generator that flows power through cables to a pair of electric motors below the front axle, each connected through a reduction gear to a front wheel.
The system adds about 140 pounds on the front axle, roughly 100 pounds for the flywheel-generator package, and another 60 pounds for power electronics, cooling systems, and cables. To offset this, the 911 GT3 R Hybrid replaces the RSR's steel roof with one made from magnesium.
That the system works as well, and as powerfully, as it does is "a testament to the guys at Weissach," Long said. But like many, he was a skeptic at first. "I saw it as a project" or a technology test, he admitted, "until I got in, and saw how refined it was."
That was when "I knew we were onto something," said a grinning Long. "I just kept asking myself, why hasn't Bergmeister been talking more about this? It's amazing."
The results of improving the 911's efficiency by recapturing wasted brake energy? The standard 911 GT3 RSR can do 10 laps of the Nurburgring circuit on a tank of gas; the hybrid saves enough fuel to do an entire extra lap before having to pit.