The Story Of Volkswagen’s Mysterious W10-Powered BMW M5 Might Not Actually Be True

In recent weeks, there’s a good chance you read about one of the most radical Volkswagen prototypes ever: an E39 BMW M5, powered by a rare and mysterious W10 engine, and not just driven but dailied by VW’s brilliant engineer-turned-executive Ferdinand Piëch. It’s a mind-bending tale from the golden age of VW—and it might be too good to be true.

You might think those are fighting words coming from someone who didn’t get hands-on with the W10 M5 like Drivetribe did for a recent video (see below). Not only did they drive the car, but they recorded its performance on a dynamometer.

But our collective knowledge of the W10 M5 is my domain, because yours truly brought this story to the wider internet’s attention back in 2023 on The Drive. I chased the W10’s trail until it went cold, ending up with a dissatisfyingly incomplete account that’s nevertheless the basis of its accepted history. Even after Drivetribe’s new video, it looked like the W10’s lore would remain a puzzle forever, and one missing most of its pieces at that.

That’s when I got an interesting message request on Instagram. It was from someone claiming to be involved with the W10 prototype’s development, and what they told me turns what we know about the engine (and the M5 it was installed in) on its head.

The Legendary VW W-Engine

But first, we need to speedrun the VW W engine’s history up to this point. A W engine (as VW interpreted it) is basically a pair of its “VR” narrow-angle V engines with a shared crankshaft and block. Compared to an engine with the same number of cylinders and displacement, a VR motor is shorter than an inline, but narrower than a V. Its cylinder banks share a single head, making it a tightly packaged engine configuration. It allows more cylinders to fit in a tighter space, which is enough to make any German blush (regardless of whether they’re an automotive engineer).

VR engines powered a range of VWs starting in 1991, with W engines arriving in 2001 and both configurations bowing out in 2024. Whether emissions regulations, cost of manufacturing, or other, less easily quantified reasons are to blame, VR and W engines’ advantages evidently didn’t justify their drawbacks to VW. Still, they left indelible marks on the automotive landscape as symbols of VW at (arguably) its peak. Between W12s’ exclusivity and W8s’ short life on the market, they’re unique enough to make any car they power interesting. But none more so than the W10.

That’s part of what drew us all to the W10 when it surfaced online in 2023, and again these last few days. It seemed like the kind of engine that only Piëch’s VW would have the interest and know-how to make. Yet despite the presumed connection to VW, no solid link was ever established. It had no VW casting marks. VW spoke of the configuration in service literature, but only as a hypothetical. An old rumor on VW Vortex (supposedly originating from The Detroit News) from 2003 suggested VW meant to make a long-wheelbase W10 Phaeton, but that car never manifested. When I last contacted VW for some information, any information, it had none to share. Many of the W engine program’s experts are retired or deceased; VW had seemingly lost some of the institutional knowledge to even tell us if it ever made a W10.

But as it turns out, the truth was always out there, even if not at VW, because according to my source, the Wolfsburg-based company didn’t make these W10 engines.

SWR Motorsport

My source for this information requested to remain unidentified, but claims to have worked at a defunct German prototyping firm called SWR Motorsport. The source outlined company relationships with OEMs, prominent race teams, and suppliers, for whom the company performed advanced engineering and made prototypes. SWR was characterized as the racing offshoot of German valvetrain supplier Schrick, which is where the S in SWR comes from. The W meanwhile stands for its other cofounder, who throws a curveball into the story of the W10 as we know it: Dr. Wolfram Willeke.

Willeke was apparently an alumni of Ford Germany’s motorsport program, having previously worked on the Mk3 Escort RS1600i. So far, Willeke’s role in the story has seemingly been confused with that of Dr. Sabine Willeke, an engineer attributed for many of VW’s in-house W engine developments. The two have even been referred to interchangeably at times, with some sources (like the W10 M5’s seller GDM Motors) treating Wolfram as the nickname of Sabine. But these instead seem to be two separate people who, by sheer coincidence, shared a last name and worked independently on the same advanced engine program. And no, they probably weren’t married; my source indicated they knew SWR’s Wolfram, but not VW’s Sabine. (I tried to reach Sabine on LinkedIn to verify this, but she did not respond to my inquiry.)

My source indicates that Wolfram Willeke would come to run SWR himself after Schrick pulled back, and that’s where the W engine’s story begins. After Piëch famously conceived of the W engine on the back of an envelope in 1997, he and VW’s powertrain lead Karl-Heinz Neumann are said to have formed a team at VW to develop the idea. But after two years and little to show for their efforts, my source says Neumann contracted SWR to produce a prototype W12. Despite a permanent staff of no more than a dozen people, my source says SWR put a working W12 into an Audi A8 mule in only about a year. The shop would apparently go on to produce multiple prototype W12s, for everything from a canceled Bentley Le Mans car to the original W12 Syncro concept. And of course, the W10, a less fruitful program that my source was able to shed new light on.

The source doesn’t remember when exactly the W10’s development began, but noted that the E39 M5 it was tested in was a one-year-old used car at the time. That’d put this chapter somewhere between 1999 and 2004. They told me that the W10 (along with other prototypes in the VR-W family) was based on VW’s original architecture for the concept, 1991’s 2.8-liter VR6. Apparently, the W10 isn’t an amalgamation of two VR6-derived VR5s as I assumed when I dug up this engine in 2023, but an entirely new engine, complete with a custom-cast aluminum block instead of the VR6’s cast iron. Well, not all-new; SWR allegedly repurposed as many of the 2.8’s components as possible.

The pistons and connecting rods were said to be standard OEM parts, along with the valves, valve springs, and much of the front-end timing assembly down to the VVT actuator. They didn’t remember how the crankshaft was manufactured, though they remember the first W12 and VR5 prototypes utilizing laser-welded sections of the 2.8’s crank. The W10’s cylinder heads were also initially made from three cut-up VR6 heads per side, though later prototypes apparently had cast heads. The camshafts were said to have similar profiles to the VR6, but were apparently unique. It’s no Schrick question to ask who might have produced them.

As for the W10s themselves, the source could only recall three existing, all of which are accounted for today. One incomplete engine is in the hands of a specialist VW mechanic, while the other two are at GDM Motors—one on a stand, the other in that E39 M5. The M5’s story apparently isn’t what we’ve heard so far, though. While VW may have paid for SWR to develop the W10, my source indicates the M5 was SWR’s in-house test mule. It allegedly visited VW only for a few days for evaluation, and VW is said to have never taken delivery of a complete W10 engine.

A VW Exec Dailying A BMW?

 

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It’s out-of-character for an OEM to test an engineering flex of an engine like the W10 in a body that isn’t its own, so the W10 powering an M5 (rather than something like an A8) fits with this SWR story. As is established, the E39 makes sense as a testbed for the W10 due to its large engine bay, sturdy transmission, and balanced chassis. Because the prototype W10 weighs about as much as the M5’s stock V8, it wouldn’t upset the handling. This may also explain why VW had no info to share about the W10 program when I last contacted it for information on the project. (I did not get a reply when I reached out to VW of Germany.)

But this would also mean the M5 couldn’t have been dailied by Piëch, as the apocryphal version of its history so far goes. Instead, my source says that Piëch dailied the aforementioned W12 A8 mule, which the CEO of the VW Group would obviously prefer being seen in to a BMW. It doesn’t mean he didn’t wheel around the W10 M5 at least once, but it would dispel some of the car’s mythos. So would my source’s apparent reality check about the M5’s reliability.

The Legedary M5 Apparently Had Some Issues

They say that the W10 engine was, to nobody’s surprise, a little thirsty but “reliable and powerful.” They remembered the output exceeding 450 horsepower, and Drivetribe’s M5 video did show a dyno result of 480 hp and 436 ft-lbs of torque. We don’t know the dyno correction factor, so we can’t say if that’s at the wheels or the estimated crank output. But we can apparently say that the BMW’s manual transmission was the mule’s Achilles heel. Its input shaft had to be modified to work with the W10, and my source remembers it breaking on at least three occasions.

That’s the downlow on the W10 program, seemingly the least successful of VW and SWR’s offspring. SWR would apparently go on to prototype turbochargers for the Bugatti Veyron, as well as that Bentley Le Mans W12 that never raced. Apparently, that engine was tested in a Lola chassis before disappearing into a VW warehouse somewhere. (It was supposedly swept aside as VW Group’s Le Mans strategy shifted to Audi’s game-changing TDI prototypes.) As an aside, SWR also apparently produced the 1.4-liter, twin-turbo V6 that powered the Brabus version of the Smart Roadster. I just found that too interesting to leave out.

How Did The W10s Escape The Shredder?

Alas, all things end. SWR allegedly became the subject of dispute in the divorce proceedings of Wolfram Willeke, whose to-be ex-wife was apparently a financier who was unsatisfied with her share of the profits. North Data indicates the company was liquidated in 2012, though my source says it was spiritually reformed in the same facilities as MPE Engineering. Stickers for both businesses are still on the car though, with SWR’s logo adorning the ECU in the glove box and MPE’s on the rear bumper.

As for how the W10 engines escaped the fate of most prototypes—the industrial shredder—my source speculated they may have become collateral to settle SWR’s liquidation. They also indicated that the W10 M5’s seller, GDM Motors, may be connected to some of SWR’s former motorsport partners. One of them is the subject of another tale that could reignite one of the greatest cheating scandals in racing history, though that’s one I have to finish researching before it sees the light of day. Stay tuned.

Top graphic images: GDM Motors/VW