A 2-rotor, 11.6-liter rotary diesel engine was almost a thing

The rotary engine had its moment of automotive glory with Mazda, but while the Japanese automaker’s rotary engines where small-displacement, high-revving, buzz bombs, one American startup tried a very different approach, designing an 11.6-liter big-block rotary running on diesel for marine applications.

The company was Rotary Power International, and the engine was the Model 2116R. According to press materials dated August 2000 unearthed by Car Expert, the 2116R was a two-rotor engine with an aluminum block, 8.5:1 compression ratio, and a stratified direct injection system, as well as spark ignition. This would have allowed the 2116R to run on gasoline as well as diesel, or even kerosene or jet fuel, according to the company.

Rotary Power International quoted an output of 1,000 horsepower at 3,600 rpm and 1,550 pound-feet of torque at 2,400 rpm.

The company also discussed other, larger rotary marine engines, including the four-rotor, 23.1-liter 4231R

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The EPA’s Vehicle-Size Classes Make No Sense—Or Do They?

If you’ve heard or read terms like “subcompact,” “mid-size,” and “large” bandied about for various cars and found yourself at times wondering what, exactly, puts any given car into one of those buckets, you’re not alone. There are many ways to classify car sizes, from weight to exterior dimensions to interior volume. The EPA takes the latter path, not for its emissions regulations, but for its fuel economy reporting.

OK, so interior volume—that seems like a reasonable measure of a car’s size, right? To have a large interior volume, a car would presumably have to have an exterior size large enough to enclose it, and that should scale from small to large in a pretty intuitive fashion, right? Well, sort of. But before we get into why it’s only “sort of,” let’s take a look at the classes as they sit now:

EPA Sedan Size Classes by Interior Volume (Passenger

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