Unfortunately, we didn't really get a feel for how this lightness impacts handling because we were limited to very brief, largely straight-line runs in prototypes at Hyundai's Namyang Proving Ground outside of Seoul. What we can tell you is that at first blush, the Sonata Hybrid accelerates and shifts gears like a normal family sedan. By this we don't mean "normal for a hybrid"– it just gathers speed in an utterly familiar, drama-free fashion. Yes, if you're reserved with the throttle, you'll generally be able to accelerate to around-town speeds without awakening the 2.4-liter until the battery's depleted, but when driven as you would normally, you'll realize that Hyundai's decision to go with a conventional stepped gearbox over a CVT was a smart choice as the drivetrain acts and sounds like any other four-cylinder powertrain – no wonky stretched rubber band sensation or soundtrack that many CVT units deliver. We did notice a couple of incidents where the transmission 'clunked' a bit from gear to gear under part throttle, but Hyundai engineers acknowledge that they still have some bugs to work out before the car enters production.
Hyundai quotes a total combined power estimate of 209 horsepower at 6,000 rpm and 194 pound-feet of torque. Both figures are actually slightly better than the gas-powered Sonata's 198 hp and 184 lb-ft, although obviously the Hybrid is heavier. The gas-only car already has class-leading fuel economy figures of 22 miles per gallon in the city and 35 on the highway, while Hyundai estimates the hybrid will drum up 37 mpg in the urban cycle and 39 mpg out on the highway. As we've already observed over 40 mpg on the highway in a non-hybrid Sonata, we're guessing that the factory estimates may be under-reported a bit. Even still, as with most hybrids, you're really only likely to garner huge fuel savings – about 40 percent – if most of your driving is conducted in the city, not out on the open road. Either way, Hyundai has yet to officially reveal any other performance metrics, but we did note a Powerpoint slide suggesting 0-62 mph in 9.2 seconds, which seems a tad conservative.