North American Int’l Auto ShowDETROIT – Mazda Motor Corp. likes its new 2.3L DISI turbocharged 4-cyl. engine a lot. It thinks buyers will too.

So much so that larger V-6s may have a less certain future at the company that takes quite seriously its fun-loving “Zoom-Zoom” tagline.

The twin-cam 2.3L DISI 4-cyl. was introduced late last year for the high-performance Mazdaspeed6 and will be the standard engine for Mazda’s shapely new CX-7 cross/utility vehicle when it launches this spring.

For the Mazdaspeed6, the power-packed DISI 4-cyl., which uses direct-injection technology to increase power and fuel efficiency, develops an eye-opening 274 hp, or 119 horsepower per liter.

All-new CX-7 bucks trend towards 6-cyl. power for small, midsize CUVs.

For the CX-7, the turbocharged 4-cyl. makes 244 hp, the power and torque curves adjusted to develop more low-speed grunt suitable for a CUV.

Either variant handily outpowers the 3L DOHC V-6 Mazda uses in the standard Mazda6 and other models.

The impressive 4-cyl. won a Ward’s 10 Best Engines award for 2006, its first year of production.(See related story: Mazda Motor Corp. 2.3L DISI Turbocharged DOHC I-4)

But while 6-cyl. power is becoming all but standard equipment for sport sedans and CUVS, and many customers might feel “cheated” by a 4-cyl., Robert Davis, Mazda North American Operations senior vice president- product development and quality, thinks the new DISI 4-cyl. will not leave anyone disappointed.

More important, Davis says, the new high-tech, high-powered 4-cyl. may be a better engine to support Mazda’s brand image.

Davis says the lower weight of the 2.3L DISI 4-cyl. vs. the longstanding 3L V-6 enhances handling and steering feel, important dynamic attributes for Mazda.

And although the CX-7’s variant of the 2.3L 4-cyl. makes 30 hp less than in the Mazdaspeed6, Davis says it really is not a “downgrade.”

“The engine’s not dialed back so much as the (power and torque) curves are pulled to the left,” says Davis, meaning power and torque peaks occur at lower engine rpm.

This adjustment of the engine’s power characteristics means the CX-7 will be more responsive at lower speeds, which Mazda developers believe is an acceptable tradeoff for the higher-rpm power found in the Mazdaspeed6 variant.

Moreover, despite power increases as large as 59 hp compared with Mazda’s Ford Motor Co.-derived 3L DOHC V-6, the new 2.3L DISI 4-cyl. provides a solid fuel economy improvement.

Davis points to the 18 mpg (13 L/100 km) city and 24 mpg (9.8 L/100 km) highway ratings for the all-wheel-drive CX-7, a substantially sized, quasi-premium CUV that also weighs 3,929 lbs. (1,782 kg), or almost 300 lbs. (136 kg) more than Toyota’s new RAV4 fitted with a 3.5L DOHC V-6.

Given the handling and fuel-economy benefits of using the new 2.3L turbocharged 4-cyl. vs. a 3L V-6, does that mean V-6s are an endangered species at Mazda?

“We’ll see how the market reacts,” says Davis. “I think (the) CX-7 will be a big indication of acceptance.”