The first BMW 6 Series was an important model for the Bavarian brand for a number of reasons. One of the most important was the fact that it introduced the first M6 into the world. Yet if you couldn’t afford a full-on M6 (M635CSi in Europe), you could get a less powerful, but still fast, BMW 635CSi, which boasted a big inline-six and a healthy amount of power. In this video, we actually get to see a BMW 635CSi with a lot more power than it originally had back in the ’80s. A lot more power.
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Under the hood of the BMW 635CSi hid a couple of different engines over the years. Initially, in 1978, the BMW 635CSi had an M90 straight six unit under the hood which shared a lot with the iconic M88/1 used in the M1.
Later on, the BMW 635CSi received a 3.4-liter straight six in 1982 and then a 3.5-liter unit in 1988. Both were still rely heavily on the M88/1 mill from the M1. The car in the video below claims to have a 3.5-liter straight six under the hood, which means it should be one of the last to be built at Dingolfing. According to the video below, the engine was heavily modified to produce 1,200 HP. That’s a long stretch from the 208 HP initially pushed out by the mill.
Apparently, the engine is now running on E85 fuel and comes with new pistons, a ported head, custom camshafts, a PPF exhaust manifold, individual throttle bodies and, of course, a huge PT 7675 Precision gen 2 turbocharger. There’s no way you could get that much power from a naturally-aspirated engine. To handle all that extra torque, this modified BMW 635CSi gets a gearboxfrom an E46 M3 model with Tilton twin plate clutch.
As you can see, the end result is a gracious, elegant tire shredding machine. Enjoy!