America Rejects Diesel Cars, This Custom Turbodiesel BMW 135i Proves Us Wrong

In the states, diesels are reserved for things like 18-wheeler trucks, flat-bed wreckers, and pickup trucks. Of course, there's also the occasional BMW X-whatever holding up the line at Starbucks while they struggle to make six pumpkin spice lattes with matching cake pops for each. But regular old diesel coupes and sedans? That's been unheard of since the Oldsmobile 350 diesel bit the dust.

With that in mind, we'd understand your surprise if you didn't see this M57 diesel-swapped 2011 BMW 135i driving around Munich, Geneva, or Bucharest. Instead, this car hails from Michigan, in a town a little less than three hours northwest of Detroit. Make no mistake, everything under the hood of this tiny little sports coupe is of fine Bavarian stock (unless the bits other than the engine were made in Mexico or something).

Gone is the stock gas engine. In its place is a BMW M57 straight-six diesel engine. It's a common-rail-injected three-liter unit with factory turbocharging from either Garret or Borg Warner, depending on if it's a single or twin-turbo setup. Even in OEM condition, the M57 was almost as appealing to Euro-diesel fans as a turbo Cummins would be to lifted truck enthusiasts.

Needless to say, this is the kind of custom build that needs a full strip down. Everything from the stock engine and transmission to vital suspension and braking components found their way onto the shop room floor when this build got started. With little more than a bare shell and chassis remaining by the time it was all finished, it was time for the fun part.

Happily, the stock N55 gas engine this car left the factory with is the same displacement as the M57 diesel now under the hood. Not to say pulling off this engine swap correctly was easy as putting LEGO bricks together. Making the engine work in harmony with a ZF 8HP eight-speed automatic transmission must have been a decent challenge in and of itself. The fruits of all the labor mean this diesel Bimmer has one of the most overbuilt transmissions to come out of Germany since at least reunification.

This 135i is going to need an overkill transmission. With twin ProTurbo Stage 2 turbochargers, aftermarket forged camshafts from Colt Cams in Canada, and a tune that needn't comply with Michigan's non-existent emissions testing, this is bound to be one unregulated beast of a thing. With a wicked four-wheel coilover setup from Öhlins, upgraded brake rotors and pads, and Firestone Firehawk Indy 500 on 18-inch VMR wheels, there's much to like about this car's internals.

With a splendid-looking Crimson Red (A61) paint job, 1M-style fender flares and bumper covers, quad exhausts, and a custom 135d emblem to complete the look, this car almost looks like it left the factory like this. It's a level of craftsmanship applied to European engineering in a way you almost never see in North America.

Inside, leather-trimmed bucket seats with flying-buttress style bolstering are delightfully anointed with M Division badges. With the center console out of a BMW 240i and the touch-screen infotainment screen from an M2, the Bavsound audio system has some fairly remarkable interior trim to bounce bass off. The subwoofers out of a mid-2010s M5 make sure of that.

All in all, this has to be one of the most unique custom performance coupes in North America today. The funny thing about it all is that it'd probably blend into a traffic jam in Berlin, Lucerne, Paris, or London. But in Detroit, New York, or Los Angeles, this is a breed of car that's nearly one of a kind. That's why the selling price for this car on Bring a Trailer of $52,135 actually sounds very fair indeed.