Powertrain Poster Child: Mazda Motor Corp.'s DISI 2.3L Turbocharged DOHC I-4

It's hard for us to believe 2008 marks the third 10 Best Engines appearance for this one.

When the engine launched in 2005 for the '06 Mazdaspeed6, it was a radical piece of work — something we've come to expect from Mazda's powertrain unit.

This engine is the poster child for how affordable horsepower has become. Yes, there are models from Japanese auto makers with hyper-tuned turbocharged 4-cyls. that make more power and torque, but the Subaru WRX STI and Mitsubishi Lancer Evolution cost 10 grand more.

Now, however, there is some new competition. Chevrolet's new 2.0L turbocharged 4-cyl. in the HHR SS is making 260 hp (130 hp/L), and Chrysler's Dodge Caliber SRT4 slams out 285 hp (119 hp/L) from its turbocharged 2.4L 4-cyl. Both, at $22,995, are within the cost of some floor mats from the price of the Mazdaspeed3.

But our testers still consider Mazda's DISI 4-cyl. the best of the breed, however.

ENGINE SPECS

Engine type: 2.3L Turbocharged DOHC I-4

Displacement (cc): 2,260

Block/head material: aluminum/aluminum

Bore × stroke: 87.4 × 94

Horsepower (SAE net): 263 @ 5,500 rpm

Torque: 280 lb.-ft. (380 Nm) @ 3,000 rpm

Specific output: 114 hp/L

Compression ratio: 9.5:1

Assembly site: Hiroshima, Japan

Application tested: Mazdaspeed3

EPA fuel economy, city/highway (mpg): 18/26