Spannerhead Dot

BMW’s Tri-Turbo Diesel: A Plumber’s Nightmare

January 29, 2012 by Matt

BMW Tri Turbo Triple Diesel Engine Motor M550d X5 X6 M50d

Contrary to popular perception, there is some precedent for this.

No, not for mounting three turbos on a diesel engine—that’s new—but for BMW releasing more “mundane” M-tuned versions of regular road cars.

See, at the moment, the larger part of the BMW enthusiast community is undergoing a kind of soul-searching existential crisis, wondering how BMW’s M division could have ever stooped so low from their racing-derived roots as to release a trio of diesel-powered models: the M550d, X5 M50d and X6 M50d, all fitted with the above engine.

On the surface, it does indeed appear that BMW M has completely sold out. For years, enthusiasts could count on a few givens from the Bavarian automaker’s tuning arm: High-revving, bespoke, naturally-aspirated engines and firmed up, immensely capable versions of BMW’s regular sedans and coupes. With the release of an M-tuned, diesel-powered SUV, it would certainly seem like BMW M has finally abandoned the last of their core convictions, jumped the shark, so to speak.

Take heart, though, BMW fans; it’s not as bad as you think, for a couple of reasons:

  1. Diesel engines now have a performance pedigree. Granted, oil-burners may have won their accolades under the auspices of a major BMW rival, Audi, but with the ’06 Le Mans victory of the awesome R10 TDI, the world has finally been made safe for performance-oriented diesel-powered cars.
  2. The new models aren’t “true” M cars. Not in the sense that their nomenclature follows the M + single digit convention. When BMW M creates a new M3, M5 or M6, it truly does represent the division’s most uncompromising effort in that particular niche. However, the tuning arm does have a long history of creating “lesser” M cars, from the regular M30-powered E12 M535i, through the regular M60-powered E34 M540i and 540i M-Sport all the way to the regular N54-powered E82 1 Series M Coupe. So the long precedent doesn’t mean every car BMW M touches signals the downfall of the brand.

That said, ever since the X5 M and X6 M, I still don’t know what to say about a performance SUV from BMW. That’s…untouchable. The new X5 M50d and X6 M50d may be very impressive indeed, but as SUVs, to borrow from Clarkson, they’re utterly pointless.

As for the engine itself, shown at top, I’m eager to get more details on how it works. Top Gear reports:

The lower inertia of the smaller turbos is used to deliver “razor-sharp responses” according to BMW, while the larger one is tuned for maximum pressure when you really feel like opening the taps.

Well…yeah. That’s been the point of sequential twin turbos ever since the Germans and Japanese began fitting them to their cars in the late ’80s. More details on the engineering justifications for the extra turbo and associated complexity would be nice. Will keep you posted.

Filed under: BMW, News

Leave a Reply