Year of the Welterweights

The 13th year of the Ward's 10 Best Engines competitions finds the auto industry and its powertrain sector in acute transition entering 2007.

The U.S. domestic auto industry is undergoing a transformation to align its manufacturing capacity with new market realities. Likewise, consumers are indicating they, too, are shifting their tastes and questioning their vehicle needs in the wake of a protracted period of higher fuel prices.

All of this affects powertrain development, and 2007's 10 Best Engines award winners already reflect a changing environment.

Large-displacement engines have dominated past 10 Best Engines. Half of this year's winners displace 3L or less, and only two are larger than 3.5L. Four of the 10 winners use forced induction.

In accordance with the average lower displacement of winning engines comes a broad trend toward increased fitment of efficiency-enhancing technology in addition to forced induction, such as direct-injection gasoline (DIG) fueling, cylinder deactivation and more sophisticated variants of variable valve timing.

The landscape of powertrain development may be transforming, but rules governing the competition remain the same.

Nominated engines — 31 this year — must be available in series-production, U.S.-specification vehicles that go on sale no later than the first quarter of 2007.

Eligible engines must be available in vehicles with a base price of no more than $54,000 (adjusted regularly as an index to the average price of a new vehicle). Engines in more expensive and exotic vehicles should, by nature, be superior.

The head-to-head format generates a list of true winners, with no artificially constructed segments or sub-categories to diminish the results. All nominated engines must compete against all others.

A panel of six Ward's editors evaluated each engine using a variety of objective and subjective measures.

Heavily influencing judges' voting are fuel economy; noise, vibration and harshness (NVH) attributes; technical innovation; and power and performance — particularly specific output, or the power generated in relation to the engine's size.

For judges' lively columns on their engine impressions, go to www.WardsAuto.com.

Better than Bigger Engines: Audi AG FSI 2L Turbocharged DOHC I-4

Seems like there suddenly is a lot of small-displacement 4-cyls. pushing silly horsepower. Audi AG's turbocharged, direct-injection gasoline (DIG) 2L DOHC I-4 isn't even the most powerful among them.

But in taking its second consecutive 10 Best Engines award, the Audi powerplant demonstrates that in the new class of power-dense, forced-induction fours, all-around versatility and refinement is at least as important as big numbers.

Engineers used to look at 100 hp per liter as a moonshot number, but these new-generation boosted 4-cyls. blow right past that benchmark.

Audi wins the day with superb drivability and wicked-fun throttle response that leaves its competition, not to mention a lot of larger V-6s, feeling flat. The full whack of its 207-lb.-ft. torque peak being on hand from 1,800 rpm all the way to 5,000 rpm certainly helps.

ENGINE SPECS

Engine type: 2L Turbocharged DOHC I-4

Displacement (cc): 1,984

Block/head material: iron/aluminum

Bore × stroke (mm): 82.5 × 92.8

Horsepower (SAE net): 200 @ 5,100-6,000 rpm

Torque: 207 lb.-ft. (281 Nm) @ 1,800-5,000 rpm

Specific output: 100 hp/L

Compression ratio: 10.3:1

Assembly site: Gyor, Hungary

Application tested: Audi A3

EPA fuel economy, city/highway (mpg): 24/32

Powerful, Efficient, Magnificent : BMW AG 3L DOHC I-6

BMW AG has been scrambling lately to maintain its prime position atop the sport-sedan pecking order, as new and revitalized Japanese and U.S. competitors chip away at its brand equity.

The cornerstone of that is BMW's famous and smooth inline 6-cyl. engine.

Shackled somewhat by the sensibilities of a European-market base that demands mainstream engines remain snugly sized, BMW watched in recent years as larger-displacement V-6s worked walloping horsepower advantages of as much as 70 hp over its 3L straight-six in sport sedans. Something had to be done.

The answer is this magnificent engine, the 12th generation of the hallowed inline 6-cyl. Using a raft of new power- and efficiency-enhancing tweaks, BMW narrowed the power gap with the half-liter-larger premium V-6s to the point where the engine's intrinsic design advantages aren't overshadowed by horsepower comparisons, alone.

ENGINE SPECS

Engine type: 3L DOHC I-6

Displacement (cc): 2,996

Block/head material: magnesium-aluminum/aluminum

Bore × stroke (mm): 85 × 88

Horsepower (SAE net): 255 @ 6,600 rpm

Torque: 220 lb.-ft. (298 Nm) @ 2,750 rpm

Specific output: 85 hp/L

Compression ratio: 10.7:1

Assembly site: Munich, Germany; Steyr, Austria

Application tested: Z4 3.0si

EPA fuel economy, city/highway (mpg): 20/30

So Sweet, Smooth, Willing: BMW AG 3L Turbocharged DOHC I-6

Yeah, auto makers and their powertrain engineers have claimed for years some latest pairings of engines and turbochargers have “eliminated” turbo lag, the wait-to-accelerate feeling that has been the bane of turbocharged automotive powerplants. Well, BMW AG's actually done it.

So sweet, so smooth, so willing, so immediate is BMW's all-new turbocharged 3L DOHC I-6.

We're convinced enthusiasts won't know BMW's hallmark inline 6-cyl. engine has forced induction.

BMW, in fact, had quickly tired of its “standard” 3L DOHC I-6 taking a back seat to larger V-6s dealing out in excess of 300 hp. It called in forced-induction boffins from turbocharger expert Mitsubishi Heavy Industries Ltd., which helped engineer the new N54 twin-turbo setup, making the first BMW turbocharged gasoline engine since 1981.

ENGINE SPECS

Engine type: 3L Turbocharged DOHC I-6

Displacement (cc): 2,979

Block/head material: aluminum/aluminum

Bore × stroke (mm): 84 × 89

Horsepower (SAE net): 300 @ 5,800 rpm

Torque: 300 lb.-ft. (407 Nm) @ 1,400-5,000 rpm

Specific output: 100 hp/L

Compression ratio: 10.2:1

Assembly site: Steyr, Austria

Application tested: 335i

EPA fuel economy, city/highway (mpg): 19/29

A Diesel to Die For: DaimlerChrysler AG 3L DOHC V-6 Turbodiesel

Two identical cars. One has a gasoline 3.5L V-6, the other, a 3.2L V-6 diesel.

The gasoline car runs from 0-60 mph in 6.5 seconds. The diesel car takes a tenth of a second longer to get there but makes up for it with 35% better fuel economy.

With $3.50-per-gallon gasoline anything but a distant memory, you'd take that diesel, wouldn't you? We sure would.

“A game changer” is the summation of one 10 Best Engines judge of the DaimlerChrysler AG 3L DOHC V-6 turbodiesel, an all-new, 72-degree vee architecture developed by DC's Mercedes-Benz unit to replace its inline 6-cyl. turbodiesel.

It gets 27 mpg city and 37 mpg highway, and has noise-, vibration- and harshness- quality levels comparable to gasoline engines. Goodbye to that nagging perception issue. Just as important, the new V-6 wields a hefty performance hammer.

ENGINE SPECS

Engine type: 3L DOHC 72° V-6 Turbodiesel

Displacement (cc): 2,987

Block/head material: aluminum/aluminum

Bore × stroke (mm): 83 × 92

Horsepower (SAE net): 208 @ 3,800 rpm

Torque: 400 lb.-ft. (542 Nm) @ 1,600-2,400 rpm

Specific output: 69 hp/L

Compression ratio: 18:1

Assembly site: Stuttgart, Germany

Application tested: Mercedes E320 Bluetec

EPA fuel economy, city/highway (mpg): 27/37

Hemi Five Times a Winner: DaimlerChrysler AG Hemi Magnum 5.7L OHV V-8

Those who thought DaimlerChrysler AG's hulking Hemi 5.7L OHV V-8 this year would be “politically corrected” from the Ward's 10 Best Engines list probably don't know the Hemi very well.

It takes more than $3-per-gallon gasoline to change our minds about the Hemi.

Returning for its fifth consecutive 10 Best Engines win, the Hemi's intrinsic goodness and legitimate effort to improve efficiency transcend this year's fuel-price scare, in the minds of the competition's judges.

The Hemi waltzed its way on to this year's list, mostly because there's still plenty of need for traditional V-8 power, and right now, nothing's serving that need better than the Hemi.

“After several years in the market, the Hemi still feels fresh and invigorating — and sounds great,” says one editor.

ENGINE SPECS

Engine type: 5.7L 90° OHV V-8

Displacement (cc): 5,654

Block/head material: iron/aluminum

Bore × stroke (mm): 99.5 × 90.9

Horsepower (SAE net): 340 @ 5,000 rpm

Torque: 390 lb.-ft. (529 Nm) @ 4,000 rpm

Specific output: 60 hp/L

Compression ratio: 9.6:1

Assembly site: Saltillo, Mexico

Application tested: Chrysler 300C

EPA fuel economy, city/highway (mpg): 17/25

One of the Silkiest of the Sixes: Ford Motor Co. Duratec 35 3.5L DOHC V-6

Ford Motor Co.'s Duratec 35 is thrusty and refined and demonstrates decent, if not necessarily game-changing, fuel-economy (we've yet to see a “performance” V-6 sip fuel).

We can't answer for reduced emissions other than to report we absolutely didn't see any.

The Duratec 35 is particularly delightful in the mid-range, where it revs viciously with even light throttle applications. In fact, revving all over the place is one of this new engine's strong suits.

Often, larger-displacement V-6s can be slow to start revving with gusto, but the Duratec 35 delivers some of the crispest throttle response we can recall.

It scores with class-leading refinement. All sorts of low-friction detail engineering and big-ticket items, such as the deep-skirt block and weight-optimized DOHC valvetrain, make this one of the silkiest sixes.

ENGINE SPECS

Engine type: 3.5L DOHC 60° V-6

Displacement (cc): 3,496

Block/head material: aluminum/aluminum

Bore × stroke (mm): 92.5 × 86.7

Horsepower (SAE net): 265 @ 6,250 rpm

Torque: 250 lb.-ft. (339 Nm) @ 4,500 rpm

Specific output: 72 hp/L

Compression ratio: 10.3:1

Assembly site: Lima, Ohio

Application tested: Lincoln MKX (AWD); MKZ Sedan

EPA Fuel economy, city/highway (mpg): 17/24

Music To One's Ears: Ford Motor Co. 4.6L SOHC V-8

A funny thing happened while Ward's 10 Best Engines judges were pondering the expanding list of Mustang variants in search of the best way to sample the auto maker's modular 4.6L SOHC V-8: Ford's on-the-ball press-fleet coordinators hustled over one of the first examples of the Shelby GT.

Most of us didn't get out of the parking garage before scrambling for a pen to wax eloquent about this seemingly innocuous tweak to the 4.6L V-8, the brawny and vocal new generation of Ford's excellent modular V-8 family that scorched its way to a 10 Best Engines win when launched two years ago.

But really, the Mustang Shelby GT — 325 hp, 330 lb.-ft. and 0-60 mph (97 km/h) in about 5 seconds, all for about $35,000. We see more 10 Best Engines awards in the future with numbers like those.

ENGINE SPECS

Engine type: 4.6L SOHC 90° V-8

Displacement (cc): 4,604

Block/head material: aluminum/aluminum

Bore × stroke (mm): 90.2 × 90

Horsepower (SAE net): 325 @ 5,750 rpm

Torque: 330 lb.-ft. (447 Nm) @ 4,500 rpm

Specific output: 71 hp/L

Compression ratio: 9.8:1

Assembly site: Romeo, Michigan

Application tested: Ford Mustang Shelby GT

EPA fuel economy, city/highway (mpg): 17/25

Pull Pin on this Grenade: Mazda Motor Corp. DISI 2.3L Turbocharged DOHC I-4

You've seen those percussion grenades thrown in action films: Pull the pin, toss it in the room, there's a big bang and blinding flash, and everyone in the room is rendered senseless.

Imagine the analogue in the engine world, and you've got Mazda Motor Corp.'s DISI 2.3L turbocharged DOHC I-4 all but blasting its way past the competition for its second consecutive 10 Best Engines award.

Total sensory overload is how we'd describe testing Mazda's ultra-power-dense 4-cyl. in the new Mazdaspeed3 application. Turning the key and lighting off this big-boost variant of the Mazda-developed MZR 4-cyl. architecture is the equivalent of pulling the pin.

From there, 119 hp per liter in a car that weighs 3,180 lbs. That's 12 lbs. per horsepower, spittin' distance from high-dollar hardware such as Porsche Cayman.

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): 19/25

When 13 Is a Lucky Number: Nissan Motor Co. Ltd. 3.5L DOHC V-6

We wondered where Nissan Motor Co. Ltd. possibly could go with its VQ-series 3.5L DOHC V-6 after winning a 10 Best Engines award for a dozen consecutive years. After all, most contemporary engine families don't last this long, much less last this long at the top.

So where is Nissan going? To the podium for its 13th award.

The modular DOHC V-6 that launched in 1995 in the U.S. at 3L and 190 hp gradually had grown to 3.5L and as much as 298 hp — a 50%-plus hike in power from just a 17% increase in size.

But for the fourth-gen '07 variant, the VQ35HR, there's a critical new structural ladder frame, an enlarged crankpin and crank journal diameter, a new cylinder-head design, a trick new asymmetric piston skirt and longer connecting rods, in addition to a raft of friction-reducing updates.

ENGINE SPECS

Engine type: 3.5L DOHC 60× V-6

Displacement (cc): 3,456

Block/head material: aluminum/aluminum

Bore × stroke (mm): 95.5 × 81.4

Horsepower (SAE net): 306 @ 6,800 rpm

Torque: 268 lb.-ft. (363 Nm) @ 5,200 rpm

Specific output: 87 hp/L

Compression ratio: 10.6:1

Assembly site: Iwaki, Japan

Application tested: Infiniti G35 6MT (6-speed manual)

EPA mileage, city/highway (mpg): 19/27

Eye-Opening Performance: Toyota Motor Corp. 3.5L DOHC V-6

Winning its second consecutive 10 Best Engines award with the 3.5L DOHC V-6 used in the Lexus IS 350 sport sedan, Toyota Motor Corp. has no difficulty scoring top marks in the realm of special technical effort.

Direct-injection gasoline technology can be found on numerous engines powering vehicles in a wide range of prices. But Toyota, with the 2GR-FSE V-6, adds an intriguing extra layer by blending a more-conventional port-injection system with DIG to optimize the advantages of both fueling designs.

In low- and part-load conditions, each cylinder's direct- and indirect-injection fuel injectors are used according to the desired performance: emissions reduction, low-speed torque enhancement and reduced fuel consumption.

The 2GR-FSE also delivers superb drivability and eye-opening performance.

The 3.5L DOHC V-6 is a thrilling sport-sedan engine that compromises nothing in terms of refinement and fuel economy.

ENGINE SPECS

Engine type: 3.5L DOHC 60° V-6

Displacement (cc): 3,456

Block/head material: aluminum/aluminum

Bore × stroke (mm): 94 × 83

Horsepower (SAE net): 306 @ 6,400 rpm

Torque: 277 lb.-ft. (376 Nm) @ 4,800 rpm

Specific output: 87 hp/L

Compression ratio: 11.8:1

Assembly site: Kamiga, Japan

Application tested: Lexus IS 350

EPA fuel economy, city/highway (mpg): 21/28