As singularly dedicated to efficiency as the Volkswagen Group's Bugatti Veyron is to speed, the XL1 was created to achieve the unthinkable: To travel 100 kilometers (62 miles) using only a single liter of fuel, a feat that equates to 235 mpg. Moreover, this isn't an auto show fantasy - it's a car that you might soon see on the road in Europe.
Thanks to impressive aerodynamics, scads of carbon fiber and a "cost is no object" engineering philosophy, the XL1 actually manages to exceed that goal and hit 261 mpg in European testing, a figure that isn't likely to be surpassed by another production car any time soon.
Join us as we head to VW's world headquarters in Wolfsburg, Germany, to test out this futuristic mpg machine.
Lower than a Lamborghini Gallardo, shorter than Volkswagen's subcompact Polo and, at only 1,753 lbs., lighter than just about anything on the market, the XL1 is a mid-engined, diesel-electric plug-in hybrid that traces its roots to the ultra-minimalistic 1-Liter concept that Volkswagen unveiled back in 2002.
Like the 1-Liter, the XL1 was designed with an extreme focus on cheating the wind. Along with a slippery, tapered body shape, it boasts myriad drag-reducing details, including a completely enclosed underbody, rear wheelhouse fairings, active grille shutters and camera-based "e-mirrors" in place of conventional side-view mirrors.
Although it trades the 1-Liter's narrow, aero-enhancing tandem seating and canopy roof for a more practical offset seating arrangement and butterfly wing doors, the XL1 still boasts a drag-coefficient of just 0.19 - lowest of any production vehicle - meaning precious little energy is wasted in knifing through the air.
The XL1's parallel hybrid system consists of a 47-horsepower, 0.8-liter two-cylinder diesel, a 27-horsepower electric motor and a seven-speed dual-clutch automatic. The transversely-mounted setup is capable of sending a maximum of 67 horsepower and 103 lb-ft of torque to the rear wheels, enough for the featherweight two-seater to amble from 0-60 mph in 12.7 seconds.
A 5.5-kWh lithium ion battery pack mounted between the front wheels furnishes 31 miles of EV only range - as long as the driver isn't in a rush - while a 2.64-gallon fuel tank theoretically boosts total range to 749 miles.
Extensive use of carbon fiber-reinforced plastic throughout the XL1 helps to cut weight and ease the burden on the diminutive powertrain. The central monocoque, all body panels and numerous other components are made of CFRP, aluminum is used for the crash structures and much of the suspension and magnesium is employed in several structural elements as well as the wheels.
Naturally, all of those lightweight materials trim mass but also add significantly to the price tag, which will likely be somewhere north of $120,000 if Volkswagen decides to sell the XL1 outright (right now, a leasing program is looking more likely). Just 250 examples will be built, with availability limited to Europe.
On public roads, the XL1 will be a rare sight indeed, though we'll likely see its fuel-saving tricks trickling down to numerous more mainstream VW Group models in the future.
On the road
Duck under the door and slide behind the small-diameter, flat-bottomed steering wheel, and you're greeted by Spartan yet tasteful appointments and an unusual juxtaposition of high-and low-tech touches. For example, the iPhone-shaped e-mirror displays incongruously share door panel real estate with old-school manual window cranks that save precious pounds over electric windows.
Fashioned from molded wood fiber and finished with a carbon-look appliqué, the dash is all business, with few buttons and a small Garmin navigation display that also furnishes fuel economy and hybrid system info. Space is tight overall, but despite the narrow body, there's enough room for two to sit without bumping elbows due to the offset seats. The trunk measures just 4.8 cubic feet, so hypermilling road trippers will need to pack light.
Once underway, a mechanical chorus of whirring, humming and grinding makes it clear that sound deadening materials were most definitely a casualty of the weight saving regimen. Those used to Lexus-style isolation could easily find it cacophonous, yet we enjoyed getting the chance to listen in on the rasp of the carbon ceramic brakes, the quiet clicking of the suspension components and all the other noises that are largely filtered out from most modern vehicles.
We were also pleasantly surprised by the unassisted steering, another weight-saving throwback that rewards the extra effort it requires by painting a complete picture of the front wheels' activities at all times. Less enjoyable was the ride, which was quite firm even on the smooth roads we traversed and would borderline uncomfortable if potholes were added into the equation.
The powertrain is programmed to stay in electric-only mode for as long as possible, with the oil-burning two-banger firing up only when summoned by a heavy right foot or when the electric supply runs low. Aside from the diesel's clatter, made all the more evident by the lack of sound deadening, the transition to hybrid mode occurs smoothly, without any uncouth jolts or judders.
Regardless of drive mode, acceleration could generously be characterized as glacial - passing maneuvers essentially require a calendar. Of course, such criticism is akin to trashing the Ferrari 458 Italia for its pathetic cupholders - it's really missing the point of a rather exceptional vehicle
Leftlane's bottom line
The XL1 was never meant to be a volume-selling people's car, and given the high price, limited space and hyper-focused mission, the appeal of this expression of Volkswagen's engineering might certainly will be limited to a privileged few.
Still, there's something to be said about how the XL1 goes about accomplishing its record-breaking mileage - an acquired taste though it may be, this hybrid undeniably provides an honest, quirky and characterful drive. It may belong in the history books, but it's best appreciated from behind the wheel.
Words and photos by Nat Shirley. Some photos courtesy VW.