It's not the M5 you'd expect.
Does BMW's 6.1-liter naturally-aspirated V12 engine sound familiar to you? It should because it was developed specifically for one of the greatest supercars of all time, the McLaren F1. Back then, McLaren was not the Ferrari road car competitor it is today, churning out many models and building its own engines. Before getting into road cars, McLaren focused almost solely on motorsport. The F1 changed that. But before the McLaren F1's S70 V12 was given the green light for supercar duties, it was tested in a somewhat unusual prototype vehicle: the BMW E34 M5 Wagon. That's right. A station wagon.
Top Gear host Chris Harris also moonlights as the host of the Collecting Cars podcast, and last month he chatted with David Clark, who served as director of McLaren road and race cars from 1994 until 1998. The F1's launch happened under his watch.
Clark proceeded to tell Harris the story of how the M5 wagon (not the example pictured below) served as a test model and even divulged his own personal experiences at the wheel. "It's an outrageous thing," he said. That makes sense because of the wagon's newfound 627 hp and 479 lb-ft of torque. The regular E34 M5 had 311 hp and 266 lb-ft, so in other words, the V12 doubled its output. Amazingly, this overall power is not so unusual today in non-supercars. The Dodge Charger SRT Hellcat, to name one example, has 707 hp and 650 lb-ft.
According to Clark, that one-off M5 wagon prototype still very much exists, housed in BMW's secret collection. It's never been shown to the public. And thanks to Clark, now we know about it. Hopefully, BMW will share additional details sometime soon.
Clark also mentioned something else quite interesting: the F1 and BMW-sourced V12 program cost McLaren more than expected. BMW was initially contracted to provide McLaren with 350 engines, but only 106 F1s were built. This was costing McLaren lots of money and Clark was instructed by his superiors to negotiate a way out of the engine deal. Ironically enough, the McLaren F1 has since become not only one of the greatest cars of all time but one of the most sought after. But if you don't have at least $15 million or so to spend, don't even show up to an F1's auction.