Volkswagen W10: the mystery engine found in a BMW M5 E39

Had you ever heard of a W10 engine? We know Bugatti’s W16, the W12 used across several Bentley, Volkswagen and Audi models, the Passat’s W8, and even prototypes running a W18. But a W10? Not something we’d come across - until now.

It turns out Volkswagen also developed a W10 engine in the early 2000s, a project that was presumably meant to stay behind closed doors - but didn’t.

A German Volkswagen mechanic named Ari recently posted images on Instagram showing parts of this W10, sparking a kind of “treasure hunt” to learn more about such a mysterious and unusual engine.

The Drive was equally intrigued and got in touch with Ari to understand where the W10 came from. Ari explained that he bought the engine in 2011 from a customer, who claimed he kept it to stop it being destroyed in Wolfsburg (Volkswagen’s headquarters).

From what Ari has been able to establish, the unit he purchased is just one of three Volkswagen W10s believed to exist. Now that he has parts from one of them, his aim is to get it running.

The problem is that information on this W10 is virtually non-existent - which is exactly why Ari posted on Instagram and asked for help from anyone who might know more.

The Drive also went digging and ended up finding far more than expected: they uncovered a BMW M5 E39 fitted with this W10 and it’s for sale - we’ll get to that…

The origins of the W10

To understand how Volkswagen arrived at something as unconventional as a W10, we need to go back to 1991 and the debut of the first VR6.

That engine ultimately became the foundation for the Volkswagen Group’s signature “W” engines, created by joining two “VR” blocks on a shared crankshaft. A W12, for instance, was essentially two VR6 units combined.

The original VR6 started at 2.8 l in capacity - later growing to 3.2 l and 3.6 l - and a few years on Volkswagen derived a VR5 from it, with 2.3 l of displacement. Many will remember it in models such as the Volkswagen Bora or the SEAT Toledo.

That VR5 had a relatively short production run (1997-2006), but we now know it also served as the basis for developing the W10, with two VR5 blocks set at a 72º angle to one another. Even so, the VR5 and W10 are quite different - right down to the block material: cast iron for the former and aluminium for the latter.

Still, given Ari’s goal of getting his W10 operational - and the modular nature of these engines - it seems highly likely he’ll be able to use components from other “VR” or “W” engines to complete the build.

One of the W10s is… in a BMW M5 E39

What neither Ari nor The Drive appears to have anticipated is that, of the three W10s thought to exist, one seems to be fully functional and sitting in the engine bay of a BMW M5 E39 (!) - how did it end up there? Better still, that W10 M5 is up for sale.

The car was “discovered” at GDM Motors, a German-Belgian racing outfit involved in GT competition, which currently has this test prototype in its possession. The only BMW M5 W10 known to exist is being offered for sale, although no price is listed.

So how did a Volkswagen W10 find its way into a BMW M5 E39? The explanation may be as straightforward as this: within the Volkswagen Group - at the time led by the all-powerful Ferdinand Piëch, the “father” of the W engines - there simply wasn’t a suitable in-house vehicle to serve as a proper test bed for the new W10.

If it seems surprising they went to a rival brand for a “test mule”, perhaps it’s less surprising they picked an E39 M5 - a benchmark in its era and, for many, still the greatest M5 ever made.

According to GDM Motors, the pairing of the W10 and the BMW M5 worked so well that Ferdinand Piëch took possession of the “test mule” and used it as his daily car…

V8 vs W10

As a reminder, the BMW M5 E39 originally came with a naturally aspirated 4.9 V8 producing 400 cv - the first 10-cylinder M5 only arrived with the next generation, the E60.

GDM Motors’ listing claims the W10 delivers between 450 cv and 500 cv, alongside 550 Nm of torque - figures that exceed those of the 4.9 V8. The advert doesn’t state the engine’s displacement, but Ari estimates his W10 should be around five litres.

As with the standard BMW M5 E39, drive is sent to the rear wheels through a six-speed manual gearbox. GDM Motors also says the car weighs 1836 kg, roughly 40 kg more than the original model. That helps put the W10’s mass into context, suggesting it comes in under 200 kg.

There are still plenty of gaps to fill in this story, and we also need firmer confirmation of the W10’s specifications - but now that its existence is out in the open, more developments seem inevitable.

Source: The Drive

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