This fall, in celebration of its first 50 years, Honda will again offer a front-engine, rear-drive two-seater. Called the S2000 in reference to its engine displacement (as was the “500” in S500) and its 2000 model year, it will both honor its heritage and set new class standards in technical achievement, performance, and affordability. But what captured our imagination is its race-engine-level potency: more than 240 horsepower out of a 2.0-liter naturally aspirated four-cylinder engine.

We were recently given a special opportunity—an unusual sneak peek—to sit in, squirm under, and photograph—but not drive—a prototype S2000. Few serious details were forthcoming before its official unveiling this spring. Indeed, American Honda officials said it wasn’t certain the S2000 would be badged in this country as a Honda or offered by its Acura division, though we believe the latter is unlikely.

     We acquired much of our tech data by lying on the asphalt at Honda’s Twin Ring Motegi motorsport complex before a dawn photo shoot and wiggling as far under the S2000 as possible. We saw that the new roadster features unequal-length A-arm suspension front and rear, with the lower rear arms bolted to a tubular subframe. Mounting its engine behind the front axle helps the S2000 achieve balanced 50/50 front/rear weight distribution. With 94.5-inch wheelbase, 162-inch overall length, and 68.9-inch width, the S2000 is very close to the BMW M Roadster in dimensions.

The vehicle’s most notable component is its amazingly potent but environmentally clean engine. This all-aluminum normally aspirated DOHC 16-valve 2.0-liter inline four pumps out “more than 240 horsepower,” according to Honda. It likely will be fairly peaky power considering the 9000-rpm redline shown on the tachometer and we predict a torque-to-power ratio similar to that of the high-revving Ferrari F355’s DOHC V-8.

We can only speculate about the technical marvels Honda employs to produce specific output that challenges all-out race engines, while also meeting California Low Emissions Vehicles standards. It will likely benefit from an advanced version of Honda’s VTEC variable valve timing system, one that has at least three stages—rather than the current two—and works on both intake and exhaust cams. It’s a compact engine with closely spaced camshafts.

This Honda’s 120-plus-horsepower/liter output should make it tops in that category among naturally aspirated automotive engines. In comparison, the M Roadster’s inline six requires more than half again the displacement to make about the same total horsepower, while the ’97 Porsche 911 Turbo S could manage but 118 horsepower/liter. Even the BMW M3 GT2 race car we tested last year barely topped the S2000 at 125 ponies per 1000 cubic centimeter—and its builders weren’t concerned with such mundane factors as emissions, longevity, and low-speed driveability. Still, such potent specific output is common among Honda’s two-wheeled offerings. Regardless, it sounded magnificent when a Honda executive drove it for the photo shoot. Mated to this all-new engine is a bespoke Honda-manufactured six-speed transmission. With an estimated 2800-pound curb weight, we’re predicting the S2000 will easily whip the Porsche Boxster’s 6.0-second 0-60-mph time and may also challenge the M Roadster’s 5.1-second 0-60-mph clocking. The Honda’s narrower P225/50VR16s rear tires—compared to the M Roadster’s 245/40ZR17s—may limit start-line traction. (Showing its true prototype nature, the S2000 was fitted with Z-rated fronts, 205/55ZR16s to be precise.)