NEW YORK MOTOR SHOW: Kia chasing efficiency at expense of power

The ever-tightening Corporate Average Fuel Economy (CAFE) rules governing vehicles sold in North America is the primary reason behind the fourth-generation Kia Optima’s reduced peak power and torque outputs.

That’s the explanation given by Kia Motors America’s vice president of product planning, Orth Kendrick.

“There’s a big move afoot in the US with a real keen interest in fuel economy. And it’s not because of consumers, it’s more the government,” said Kendrick to assembled Australian journalists at the New York motor show.

“We have that in mind, but at the same time we want to deliver a great driving experience for customers, especially the guy buying the [Optima] Turbo.”

As previously reported, the newly-revealed Optima – which arrives in Australia in November – comes with a 184kW/353Nm 2.0-litre turbocharged petrol and 138kW/241Nm 2.4-litre aspirated petrol.

Both will be available Down Under from launch, but are down 20kW/17Nm and 10kW/9Nm respectively on the third-generation units. There’s also a new 133kW/264Nm option that will not be coming to Australia.

The first two are “the same engines but retuned,” according to Kendrick. “For the Turbo we have adopted a new smaller turbocharger and also we’ve done a lot of tuning work to improve driveability. That helps in low-end torque, we are able to get a lot more boost quickly at the low end. Peak power is lower, but we have worked with the engineers and they revised the transmission to suit.”

The key here, Kendrick said, is not so much in the revised gearing, but in the lock-up characteristics of the six-speed automatic transmission’s torque converter.

“With the torque converter locked up it’s a direct link from the engine to transmission, as soon as you come off from launch. Whatever power the engine produces is transmitted immediately, where the previous car – because the turbo is so much larger – when you give it full throttle there’s a lag. All the power is delivered at the high end and the transmission has to move all that.”

The smaller, but still twin-scroll, turbocharger Kia has employed works with a high static compression ratio of 10.0:1 for even sharper response. “For the average buyer who drives from stop line to stop line, what’s important is to have the vehicle react quickly at part throttle,” said Kendrick.

As a result, the trip from zero to 60mph (96km/h) is “similar at around 7.3 seconds” compared to the previous model, with far better efficiency, though Kendrick did not quote a mileage figure.

With available 95/98 RON fuel in Australia, Kendrick says that the same turbo engine could be retuned to recover some of the power loss without upsetting efficiency too much and that bodes well for local buyers, given the Aussie Optima will also receive a bespoke chassis tune to make the most of the performance.

Kendrick also explained that Kia would not pursue diesel engine options globally, however, the next-gen Optima Hybrid will return to the US in October to assist in “chasing fuel economy to hit the CAFE target.

“We have hybrid now, we’re coming out with expansion of hybrid and in the next year we will have an announcement,” he concluded. Whether that changes Kia Australia’s position on hybrid propulsion remains to be seen.