VW has hinted for some time that the diesel-electric drivetrain from its XL1 eco-supercar would appear in something a little more humble and affordable.

Now, writes Autocar, it's revealed the result of such a concoction, in the shape of the Twin-Up.

As the name suggests, it's based on the Volkswagen Up minicar sold in Europe. The 'Twin' part of the name refers to the two power sources--diesel and plug-in electric--that have been lifted wholesale from the sleek XL1's body and dropped into the Up.

Actually, that isn't strictly true--where the XL1's engine sits behind the passengers and powers the rear wheels, the Up is more conventional. The electric and diesel components sit up front and power the front wheels, just like any other Up.

"Power" is a relative term of course. Combined system output is just 74 horsepower--one pony fewer than the most potent gasoline-fired Up--but torque is a healthier-sounding 158 pounds feet. The twin-cylinder turbocharged diesel alone is responsible for 47 horses and 88 lb-ft, the electric motor 47 bhp and 103 lb-ft. As we've come to expect though, you can't simply add those two numbers together, hence the quoted combined output.

You'd expect that to deliver peppy performance, but the reality is less enticing. 0-62 mph takes a quoted 15.7 seconds--8.8 of which are used up reaching just 37 mph--and top speed is limited to 87 mph. That actually makes it slower than the base 60 bhp gasoline Up. So what gives?

Weight--at over 2,650 lbs, it's 900 lbs heftier than the XL1 and a good 600 lbs or so more than a regular Up. Despite the efforts of a seven-speed dual-clutch transmission then, it's just not that brisk.

Economy, happily, is much better. Its 31-mile electric range influences a 214 mpg European combined figure (consume with a pinch of salt) but that's more than the 50-odd miles per gallon of a conventional Up and with a twin-cylinder diesel engine, out-of-town economy is unlikely to be too thirsty.

The elephant in the room is VW's own e-Up electric car. It's quicker--little over 12 seconds to 60--and ultimately greener with no combustion engine to fuel. Sales will rely on European consumers getting over their range anxiety though--and coughing up the extra money over a regular, affordable gasoline Up.

Then there's the forbidden fruit factor--since U.S. customers won't be getting it. The Up isn't federalized for U.S. sale, which pretty much rules out special versions of it too...

Autocar reports that both plug-in Ups are expected to appear at the Tokyo Motor Show later this month.


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