Once upon a time, the initials “VR” stood for something other than “virtual reality.” From an outlandish five-cylinder engine all the way up to a 16-piston slice of cross-configuration W-layout craziness, VR engines were supposed to be the performance powerplants of the future… until they suddenly were no longer needed.

Synonymous with Volkswagen engineering since the early 1990s, this motorized type of “VR” represents the compact German V-engine layout that has a narrow 15-degree bank angle. This allows the engine to have two distinct cylinder banks but share a single cylinder head. 

Arguably one of the biggest reasons for VW to pursue the W10 over the W12, was because it would allow each VR5 engine to offset the other’s imbalances. The odd firing order within a five-cylinder engine makes it run extremely rough without the addition of balance shafts and whatnot. Photo Credit: VisioRacer/YouTube

By crossbreeding an inline engine with a V-engine block design, VW was able to transform larger transverse engines into tightly packaged power packs for its fleet of compact front-wheel drive autos. In America, the most recognizable (and readily available) versions of this VR6 engine design were found in the Golf, Passat, Corrado, and much later, the Atlas SUV.

But forget these small fry servings. What about the big-ass “W” engines that Volkswagen was whipping up by combing two VR engines? Wasn’t there supposed to be a weird-ass W10 motor in the mix too at one point?

Well apparently there was such a thing in the works at one point, and up until recently, no one really knew what happened to the W10 save for a select few VW engineers on the inside. But then out of zee blue, a posting advertising the only running VW W10 engine on the planet popped up on the jolly old interweb. So naturally, we gave it a gander, and not only does everything appear to check out, but this 10-cylinder unicorn comes packed into a completely different automobile than what one might expect.

New Millennium, New Big-Ass Engines

Before we get into assessing VW’s W-engine program, we should probably recap how the VR motor was packaged. With its tight, 10- to 20-degree bank angle, the traditional VR engine is, in essence, a staggered-cylinder block. This allows more pistons to be crammed into a shorter, but slightly beefier slanted block. Being that Volkswagen saw respectable levels of success with this performance upgrade over its traditional inline TDI/TSI engines, the search for more performance was pretty much predetermined by the time that dud of a “Y2K Bug” was expected to bite.

Come 2001, VW was ready to unveil the “Nardo” supercar concept. A period-correct/incorrect-looking piece of vaporware, teased with a whopping W12 engine. Volkswagen explained that its prototype engine was comprised of two VR6 powerplants attached to a singular crankshaft, and then appropriately angled for clearance purposes to create a four-angle W-shaped profile.

But the hunger for supercar sensationalism didn’t stop there, for Volkswagen had also created a small production run of insane-sounding VR5 engines. So why not take the same approach as the W12, and concoct a W10 out of two VR5 engines?

Photo Credit: VisioRacer/YouTube

Limited to just a few prototype test mules, VW’s W10 came with a cast aluminum block instead of the traditional iron version found in the VR engines. Each head was finished with a 4-valve-per-cylinder design, and a 72-degree valley angle to eliminate crankpin offset for an evenly timed firing sequence.

Combined from two 2.5-liter engines, the W10 reached a displacement of 5.0 liters and reportedly generated 500 horsepower and 550 Nm (440 lb/ft) of torque. This may not sound like much, but in the early 2000s, these figures easily qualified the engine as supercar-worthy.

Photo Credit: VisioRacer/YouTube

Burly Bastards Born of a Higher Power

This push for big W-engine power was fanned by a cat by the name of Ferdinand Piëch, the guy behind the Bugatti Veyron. It was rumored that Mr. Piëch was obsessed with finding ways to make the Volkswagen Group’s recently acquired roster of supercars and ultra-luxury land yachts even more over-the-top. This explains why so many W engines materialized during Piëch’s tenure at Volkswagen.

To make this all possible, Dr. Sabine “Wolfram” Willeke was tapped to formulate a series of W engines out of existing VR powerplants. It took some time for the good doctor to complete his work, but the construction of the W16, W12, W10, and W8 engines did eventually materialize.

And while Bugatti Veyron would ultimately be gifted with the W16 engine, Bentley received a vastly retuned W12 version for the Continental, while the funky VW Phaeton was made available with the wonky W as well. On the lower end of the spectrum, came the Volkswagen Passat, which was offered with a relatively weak W8 motor.

Photo Credit: VisioRacer/YouTube

So Where Did the W10 Go?

While the W16, W12, and W8 were put into production, and powered higher-end vehicles within the Volkswagen Auto Group’s portfolio, the W10 slipped into obscurity almost overnight. VW already had a working W12 that was selling fairly well, a W16 for supercar purposes, and a W8 for all of zee peasants. Why bother with a W10 that was just a compromise betwixt the lot?

From the looks of things, Volkswagen did make a set of working W10 prototypes but struggled to find a suitable platform within the VW portfolio for testing purposes. Being that Mr. Ferdinand Piëch wanted to see his W-shaped legacy completed, and every automatic transmission that was tested with the W10 engine crapped itself in no time, a most peculiar proposition was suggested.

Why not take an E39 BMW M5 with a manual 6-speed gearbox, and plop the W10 inside? The bay was plenty large enough, and while all of the W10’s power figures were a bit more robust than the M5’s OE performance numbers, the stock rear end and everything else that comes along with it should be good… right?

Photo Credit: GDM Motors

While European auto enthusiasts have argued about the authenticity (and fate) of this vehicle from the depths of grandma’s basement for damn near two decades, a recent listing of a W10-powered BMW M5 for sale on a reputable motoring company’s website has set the internet ablaze with astonishment and even more speculation.

Photo Credit: GDM Motors

We’ll let you dig into the details posted within the sales sheet, but from what we’ve been able to unearth, everything seems to check out. Additionally, the company offering the vehicle for sale has the clout and connections to obtain and sell such a unique test mule, so this M5’s authenticity is more than likely the real spätzle.

Finally, it is worth mentioning that no one knows exactly how many Volkswagen W10 motors were ever assembled and put into testing. What is certain is that there were at least three W10 motors that were produced for prototype testing, one of which is what ended up under the bonnet of Mr. Piëch’s unassuming M5.

While the W10 prototype motor never reached production, and was almost forgotten over time, things recently got a bit interesting, when images of W10 motors began popping up in Germany. Photo Credit: @unvrnunft/Instagram

As for the other two powerplants, one was presumably crushed years ago, while the other (or at least parts of it) somehow wound up in the hands of a German mechanic. While the mechanic’s Instagram photos of the disassembled W10 engine are from the summer of 2023, he claims to have obtained the engine way back in 2011. A customer had somehow saved the engine from being destroyed at VW’s headquarters in Germany and offered it to the guy either as payment or as a gift.

The engine did not come complete though. Its partially constructed cylinder head is missing an exhaust camshaft, and the deconstructed block is completely devoid of a crankshaft and anything having to do with engine timing. So unless this mechanic can somehow get his hands on Mr. Piëch’s old M5, he’s going to have a devil of a time trying to reconstruct what remains of one of the only W10 engines ever made.