Inside BMW’s Secret Toy Chest: A V12 Z3 and an E34 M5 Convertible

Watch BMW trot out some oddballs in this 50-year celebration of M cars.

byVictoria Scott|
BMW News photo
BMW via YouTube

It's not every day an automaker takes it upon themselves to give an in-depth look at a development prototype from its past; often, those cars are barely working, camo-clad stabs in the dark bound eventually for destruction. Even when they are preserved, showing them off is reserved for the manicured lawns of concours events or a secretive, reclusive group of auto journalists. So to see BMW casually trot out some of its wildest, most polished prototypes from decades past in a well-shot Youtube video is a little unexpected.

The first car featured is a drop-top E34 M5 coupe prototype with a manual transmission, finished in a stunning hue of dark purple. It has only made a handful of appearances in its life since it was built over 30 years ago; the last fresh photos I could find of it came from 2011. It features modified seats with seat-belt holders in headrests and a variable size trunk that still appears cavernous even with the ragtop down.


Next up in the collection is a V12-powered Z3M, which last seems to have surfaced in 2012. Hans Rahn, head of vehicle prototyping for BMW, notes that it's basically the same as the original Z3M, as it has the same length drivetrain. It's just that instead of a single six-cylinder, "there are two of them." Rahn also notes that the weight balance of the car is a bit nose-heavy, but that it is "definitely brutal."

The motor is not specifically called out, but a look at the overhead shot appears to identify it as an M73 naturally-aspirated 5.4-liter V12 sourced from an E38 7 Series of the same era, which would give the hot-rodded Z3 361 pounds-feet of torque, or 110 more than the hottest version of it ever actually sold to the public.

The final car shown is the legendary E31 M8 prototype, last seen in 2019. This car is the ultimate performance version of the already absurd 850CSi, which had a 371 HP 5.6-liter S70 V12 engine; this version of the car gets a Le Mans-prototype-derived variant of that V12. Previous reports about this nearly mythical machine had suggested that it sourced its V12 from the McLaren F1 or that it only made 550 hp. However, Rahn's comments about its Le Mans heritage would suggest to me that it's more likely this motor was originally developed for the BMW LMR V12, which delivered the company's first and only outright Le Mans win. He also outright states it makes 640 hp, even more than previously thought (and 60 more hp than the Le Mans race car had). It also features weight-saving aerodynamic mirrors, a custom wide body with rear brake ventilation, and a gutted rear interior for weight reduction.

All of these strange prototypes are being trotted out for BMW's 50-year celebration of the M badge. The BMW Museum in Zurich, Germany, will be exhibiting all of these cars as part of its anniversary display. It's worth checking out now if at all possible because it might be another decade before we see cars this tightly held again.

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