Ward's 10 Best Engines 2008

Now in its 14th year, the Ward's 10 Best Engines list recognizes not only great powertrains but those who create them.

Powertrain engineers toil in obscurity, getting their hands dirty building components that will be cut from solid chunks of metal and pieced together on the assembly line.

If all goes according to plan, the finished product achieves internal-combustion harmonic balance - and lures new buyers.

A mediocre effort leads to middling performance, recalls and angry consumers. A truly bad engine can tarnish an OEM's reputation for a generation.

No auto maker wants such a fate, so the power, quality and reliability of today's engines are constantly improving.

That's what makes selecting the best engines so hard. Yes, some of the least engaging entries easily are bumped from contention. But every year, we test a superb lot of powertrains that dazzle and beguile us. Reaching agreement on the final 10 is draining.

Not to mention thrilling, and educational. For those of us with gasoline in our veins, the 10 Best Engines is better than the 12 days of Christmas.

This year, we tested 37 engines, with six editors experiencing each vehicle in their routine, daily driving cycles. The 37 nominated engines include the 10 winners from 2007, plus all new or heavily revised engines for '08.

All regular-production test vehicles must be available in U.S. showrooms during the first quarter of 2008 and must have a base price not exceeding $54,000.

There aren't segments for 4-cyl. engines or V-8s. Each stands on its own, and editors award points based on how they perceive that engine competing against others like it. Points are earned for technology, power, fuel economy, etc.

This year's list is broadly indicative of the type of engines U.S. consumers prefer: Six are of the 6-cyl. variety, while two are V-8s and two are I-4s. Direct injection is employed by six of the winners, reflecting the trend toward smaller engines.

For the third time since the Toyota Prius made the list in 2001, a hybrid-electric vehicle earned a spot - this time the GMC Yukon Hybrid.

Likewise, for each year a hybrid has made the list, so has a new-generation turbodiesel. This year's winning oil-burner is the Mercedes E320 Bluetec. The arrival of several new diesels for the U.S. in 2008 will make for an exciting competition next fall.

And the new federal mandate for U.S. light vehicles to achieve 35 mpg (6.7 L/100 km) by 2020 surely will produce some fascinating new concepts to evaluate for 10 Best Engines in the coming years.

That's because behind every great engine is a team of dedicated engineers and smart management willing to focus their energies on even the most daunting tasks.
— Tom Murphy

Audi AG

FSI 2.0L Turbocharged DOHC I-4

Longtime admirers of Audi AG's engineering expertise, we've always said Audi, more than any other auto maker of the last 20 years, has been the avatar of advanced engine technologies later adopted for mainstream application.

No better case makes the point than the FSI 2.0L DOHC I-4, winning a 10 Best Engines award for the third consecutive year since its launch in 2006. The power-dense, fuel-sipping FSI 2.0L - which Audi has had in production since 2004 and couldn't be righter for the times - is the engine many auto makers only now say they're gearing up to emulate.

Audi says it was the first to combine gasoline direct-injection technology (Fuel Straight Injection, or FSI, to Audi and parent Volkswagen AG) with turbocharging for a volume-production engine.

The power- and efficiency-enhancing qualities of GDI fueling are becoming legendary, and almost every major auto maker has in production engines using GDI or plan to do so, using the technology as a cornerstone in their strategies to improve fuel economy in light of new corporate average fuel economy laws.

That sounds good to the geeks in lab coats, but those with octane in their veins are equally pleased with what Audi's wrought here. The GDI system righteously pumps up torque, particularly at low engine speeds, the only time when turbochargers aren't earning their keep.

Throttle response is horsewhip sharp and satisfying even off idle, a characteristic nobody led us to believe was going to be common with “downsized” engines.

A 4-cyl. with a power peak at 5,100 rpm might be cause to worry, but thanks to dual balance shafts and the old-school iron engine block that keeps sound from the combustion bangs where they belong, we'd put this seamless engine's noise, vibration and harshness signature up against just about any V-6.

In almost any driving situation, the FSI 2.0 acts more like a midsize V-6, and the 200 hp output is 10 hp better, for example, than the first-generation Nissan VQ 3.0L V-6 that was a slayer motor if ever there was one.

“One hundred horsepower per liter, GDI and good fuel economy - no brainer,” sums up Best Engines judge Byron Pope.

If downsizing is the future and this is downsizing, then we're “down” with it, Audi.

ENGINE SPECS

Engine type: 2.0L 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): 22/28

BMW AG

3.0L Turbocharged DOHC I-6

For the superlative counters out there, sharpen your pencils. We may set a new record here.

BMW AG's 3.0L turbocharged DOHC I-6 couldn't be more delicious if its internals were cast from solid Noka chocolate.

The seminal BMW inline 6-cyl. format is the best of the best on just about any day, but when its engineers strapped on a couple of the quickest-acting turbochargers we've ever experienced, the result is pure engineering bliss.

By today's standards, the absolute figure of 300 hp isn't necessarily that big a deal. But the 300 lb.-ft. (407 Nm) of torque is what makes the blown BMW six stand head and shoulders above the sea of V-6s that dominate the market - most sporting at least another half-liter of displacement.

And we said it last year when this engine won a 10 Best Engines award in its first year of eligibility: Over the years, many engine developers and turbocharger manufacturers insisted they eradicated turbo “lag.”

BMW, with help from turbo maker Mitsubishi Heavy Industries Ltd., finally delivers. With BMW's magnificent 3.0L turbocharged straight-6, there absolutely is no waiting.

Don't take our word for it - scan the spec box. Max torque is available at just 1,400 rpm and hangs in there, almost denying thermodynamic law or any other law you care to name, until 5,000 rpm. That's called getting the job done.

This all is overlaid, of course, on what arguably is the world's best engine architecture. BMW has brought it all together in one vicious but ultra-refined punch that combines the peerless inline 6-cyl. smoothness, the superb twin turbochargers, direct injection and dual-cam variable valve timing.

The only thing that might be lacking is the efficiency-stretching Valvetronic variable valve-lift hardware. We're told Valvetronic isn't out of the question - nudge, nudge.

The N54's Homeric torque and white-hot throttle response is all the convincing anyone needs. Stomp it and go, whenever, wherever.

And you don't necessarily have to feel like an eco-wrecker, either. Several 10 Best Engines judges reported surprise and delight at the roughly 22-mpg (10.7 L/100 km) economy during heaping helpings of heavy-boot driving.

There has been so much goodness coming from BMW's engine department over the years, it's difficult to pick an absolute winner. But the 3.0L turbocharged DOHC I-6 is the ultimate expression of BMW's famed I-6 architecture.

And just maybe - start composing your letters and e-mails now - the best BMW engine ever.

ENGINE SPECS

Engine type: 3.0L 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): 17/26

JUDGE'S PERSPECTIVE: Let's Get Small

America, the time has come to downsize.

With oil threatening to shatter the $100-per-barrel threshold and resulting gasoline pump prices locked above $3 per gallon, plus a Washington that's mandated a new 35 mpg (6.7 L/100 km) fuel-economy law, U.S. consumers will have to, at the very least, consider buying smaller cars with smaller engines.

It's true there's no substitute for a high-powered V-8 in many cases. A Mustang powered by a V-6 isn't really a Mustang in our book. A Corvette without a V-8 is unthinkable.

Certainly, it is easy to justify the need for high-torque, big-displacement V-8s in pickups - at least those legitimately used for work purposes.

But with environmental pressures building and the world's oil supply rapidly diminishing as China and India put more people behind the wheel, the time is now to bury the Me Generation once and for all and do the right thing for the common good.

Speed freaks needn't worry. If some of the cars tested in this year's 10 Best Engines competition are any indication, shrinking displacements might not be as painful as you think.

Nearly a third of the nominated engines Ward's put through the wringer were 4-cyls., with 19 of the remaining 26 V- and straight-6s.

Most offer pretty amazing performance, with engineers squeezing out 90 hp-plus per liter in five of the 11 4-cyls. tested, including the whopping 130 hp/L from the Chevrolet HHR SS 2.0L. Four of the 6-cyl. engines broke the 90 hp/L barrier.

That compares with less than 70 hp/L for Chrysler's vaunted Hemi V-8 and the Mustang and Corvette engines.

True, these iconic engines are uniquely American and push all the right buttons, but they also are the least efficient powertrain option in a market that desperately needs to change.

Meanwhile, most of the non-V-8s Ward's tested land solidly in the mid-20 mpg (11.7 L/100 km) range or better in highway fuel economy - a number even the most advanced V-8s struggle to achieve.

No one is saying we need to bury all engines with displacement above 3.0L just yet.

But the time has come - and technology and know-how available - for Americans to buy into conservation, rather than perpetuating the cycle of conspicuous consumption.

For many, smaller engines easily will do the job - and they won't leave people smacking their foreheads and exclaiming, “I coulda had a V-8.”
— David E. Zoia

Daimler AG

3.0L DOHC V-6 Turbodiesel

Every year, there is one engine, more than any other, we wish we could just bring to your house to let you try.

Daimler AG's Mercedes-Benz 3.0L V-6 turbodiesel is that engine.

See, if you haven't yet been fortunate enough to experience what we call “new age” diesel, there's only so much we can do to verbally translate how the inexorable turbine surge of 400 lb.-ft. (540 Nm) of torque at a stupefyingly low 1,600 rpm can absolutely change your stinkin' life.

You push the throttle, this engine just shoves and shoves - it's how warp drive will feel in a few hundred years.

Mercedes has more than a little history with diesel, and currently is casting some of the world's best examples.

This tidy-displacement, 72-degree V-6 is the perfect example of why contemporary high-tech diesels are so right for the times. The monstrous torque delivers all the on-the-road performance you could reasonably desire. How can you argue with torque that trashes any V-8 that comes down the road?

And hybrid-shaming efficiency means you won't feel like an environmental cad every time you put your foot down.

Yes, there's only 3.0L here, and Mercedes' own mighty gasoline-fueled AMG 6.3L DOHC V-8 out-torques this half-displacement diesel counterpart by a mere 65 lb.-ft. (88 Nm).

Correlating that torque with the 23 mpg (10.2 L/100 km) city and mind-blowing 32 mpg (7.4 L/100 km) highway fuel economy delivered by the Mercedes E320 Bluetec test vehicle almost defies logic.

And as some engineers have wistfully mentioned, diesels should appeal to the techno-buyer.

This new-age diesel checks off all the boxes when it comes to cutting-edge components: high-pressure, common-rail direct injection, piezohydraulic injectors, a variable-nozzle turbocharger. And it has an aluminum block - no engineering trifle for an engine generating such outsized combustion pressures.

Perhaps best of all, the sophisticated hardware has all but eradicated “dieselness.” Yes, you'll hear some faint clatter if you insist on hearing it - but only at idle, and essentially only outside the vehicle.

Diesels continue to fight an uphill emissions battle. Currently, Mercedes sells this diesel in 42 states (and has a rather convoluted lease arrangement in California).

The long-awaited AdBlue urea-injection system, which will reduce oxides of nitrogen emissions to federal Tier 2, Bin 5 levels, will allow vehicles powered by this superb diesel to be sold in all 50 states.

The AdBlue system will be introduced for '09 Mercedes diesel SUVs later this year and will appear on the next-generation E-Class in 2009.

Based on our impressions of the excellent Mercedes 3.0L V-6 turbodiesel, we expect it to be at the vanguard of a diesel revolution for the U.S.

ENGINE SPECS

Engine type: 3.0L DOHC 72° V-6 Turbodiesel

Displacement (cc): 2,987

Block/head material: aluminum/aluminum

Bore × stroke (mm): 83 × 92

Horsepower (SAE net): 210 @ 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): 23/32

Ford Motor Co.

4.6L SOHC V-8

We see Ford Motor Co. has drawn some criticism for its strategy of feeding buyers a steady diet of sometimes minor variations of its popular Mustang ponycar. Some don't really qualify as a “new” model or even can be designated a trimline.

But criticize? Who cares if Ford's big Mustang news for the year is a glass-roof option, or it orchestrates releases of a new “Bullitt” or a dozen other versions, as long as there's a Mustang that moves you?

That's how we feel about the dazzling 4.6L SOHC V-8 that is the signature - and seminal - Mustang engine.

There's been a sudden proliferation of variants of the chesty modular V-8. But that's OK with us. Although the differences in the recipe are comparatively minor, we definitely aren't going to argue about too many choices for the industry's most emotive-for-the-money V-8.

Returning for a fourth consecutive 10 Best Engines win, the 4.6L is beginning to construct the kind of legend that will make aficionados finally forget the long-loved 4.9L OHV V-8 of the previous-generation 'Stang.

If those two illustrate the ages-old argument about whether the overhead-valve or the overhead-cam is better, we'll take the 4.6L OHC job every time.

We did feel slightly fleeced in '07 when Ford peeled back the spec on the Shelby GT's 4.6L from the 325 hp we were led to believe it produced to the 319-hp spec on which Ford finally settled.

We're not trying to suggest we can discern 6 hp one way or the other. We're merely saying it doesn't instill faith in the “system” when such things aren't nailed down from the beginning.

Further splitting hairs is the latest variant of the 4.6L V-8, this for the '08 Mustang Bullitt and purportedly making 315 hp and 325 lb.-ft. (441 Nm) of torque.

That means we've got the “standard” (and still quite special) Mustang 4.6L at 300 hp, the new Bullitt variant at 315 hp and the Shelby GT making 319 hp. Never mind the subtle differences in torque ratings, too.

All this might be cause for criticism if it wasn't such good, wholesome fun. This is exactly the same game Detroit used to play with muscle-car buyers back in the day.

But in the 1960s, the propagation was far grander: The '68 Mustang, for example, offered five different V-8s and six distinct power ratings. Cool!

So the measly three variants of today's 4.6L SOHC V-8 are marketing child's play. We love them all, because you get the same delectable exhaust note, the startlingly effortless revs and enough refinement to make you forget all about the days of those iron-block, overhead-valve V-8s.

Editor Drew Winter says the current 4.6L SOHC V-8 “defines the Mustang. Without it, you don't have a car.”

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): 319 @ 5,750 rpm

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

Specific output: 69 hp/L

Compression ratio: 9.8:1

Assembly site: Romeo, Michigan

Application tested: Ford Mustang Shelby GT/Bullitt

EPA fuel economy, city/highway (mpg): 15/23

JUDGE'S PERSPECTIVE: GM Small Block an Old Dog With New Tricks

In the time since the first sports cars' wheels were turned in anger, few engines have made a greater contribution to vehicle performance than General Motors Corp.'s small-block OHV V-8.

Introduced in 1955 for the then-new Chevrolet Corvette and Bel Air sedan, the compact and tunable 265-cu.-in. (4.3L) “mouse” quickly outpaced Ford Motor Co.'s flat-head V-8 of the day, becoming one of the preferred means of laying down rubber in a hot rod or muscle car.

Millions of these lumps of iron and aluminum have been built over the years, with family sedans, pickup trucks and NASCAR- and Le Mans-winning racecars all having made the characteristic small-block rumble.

Now in its fourth generation, GM's OHV V-8 enters the 21st century true to the original cam-in-block formula, yet is vastly superior to its ancestors.

Modern tire-screeching variants, such as the 7.0L LS7 in the Corvette Z06, have 505 hp on tap and sport electronic throttles, plastic intakes and dry-sump oiling systems.

Others, such as the 2008 Ward's 10 Best Engines-winning 6.0L Vortec LFA in the GMC Yukon Hybrid SUV, bring the small block into the digital age with sophisticated valvetrains, cylinder deactivation and assistance from advanced hybrid-electric transmissions.

Ultimately, it was the Vortec's integration with the new 2-Mode gearbox and the polish of the overall package that won over the Ward's judges this year. However, none could refute the corruptive power of GM's other new V-8 entry: the 6.2L LS3 in the '08 Corvette.

With the optional butterfly exhaust clearing its throat under a heavy foot, the LS3 churns out 436 hp and a hard-hitting 428 lb.-ft. (580 Nm) of torque. In the lightweight Corvette, the result is a startling amount of thrust, along with impressive refinement and fuel economy, for less than $50,000.

The technical achievement of the hybridized LFA is notable in this modern era of energy conservation. But the LS3 also deserves its recognition for the world-class performance it gives America's sports car, as well as for continuing the lineage of GM's most legendary powertrain.
— Mike Sutton

General Motors Corp.

3.6L DOHC V-6

Not that we didn't like General Motors Corp.'s “high-feature” 3.6L DOHC V-6 when it launched in the Cadillac CTS for the '05 model year.

Its initial output was 255 hp and 255 lb.-ft. (346 Nm) of torque, and there were several competing similar-displacement V-6s already making in the neighborhood of 300 hp.

Although we sometimes find ourselves wishing everyone would dial back a bit on premium V-6 output, 300 hp is the new 250 hp, just like 60 years old is the new 40.

Thanks to a decade of horsepower wars, 300-hp V-6s now are the price of entry in the premium market.

To get fully in the game for the critical new '08 Cadillac CTS (and to upgrade the larger standard engine on the STS), GM powertrain engineers looked to gasoline direct injection, a technology quickly sweeping through powertrain-development departments on several continents.

Strap on the high-pressure (1,740-psi/120-bar) GDI hardware and fair-to-middlin' 255 hp becomes 304 horses. And just as important, torque also is boosted by about 8%.

Just like that, the new, direct-injected variant (internal code LLT) solves probably the most noticeable shortcoming of the original variable-valve-timing 3.6L DOHC V-6: the fizzy low- and midrange torque and resultant soft throttle response. The new GDI-equipped 3.6L V-6 has torque that gets your attention at any engine speed, and the throttle pedal no longer thinks rapidly increasing its proximity to the floor is a request that should be pondered at length.

“Solid mid-range pull,” says Associate Editor Mike Sutton. “Just pulls and pulls,” echoes Best Engines judge Byron Pope.

And the 3.6L DOHC V-6 likes to pull to the redline, too, and running to the 6,400-rpm power peak is a pleasure to be repeated, underscoring how essentially right GM Powertrain engineers got the noise, vibration and harshness.

We did note - and others have mentioned it, too - a boomy, low-frequency thrum at low rpm. We hear engineers were aware of the matter and are working out a fix that already may be penciled in by the time you read this.

And as we've noted with the latest crop of high-performance V-6s, fuel economy is not a strong suit. Despite the fact GM says GDI improves brake-specific fuel consumption by 3%, the rated 17 mpg (13.8 L/100 km) city and 26 mpg (9 L/100 km) highway figures aren't going to get anybody too far down the road toward the new 35-mpg (6.7 L/100 km) standard in 2020. A huge points-winner with us, however: The big power can be had using regular unleaded gasoline.

But we're talking the here and now, and GM's latest 3.6L DOHC V-6 is a world-class engine we'd stack up against any V-6 - and it adds serious credibility to Cadillac's goal of reclaiming its reputation for technology leadership.

ENGINE SPECS

Engine type: 3.6L DOHC 60° V-6

Displacement (cc): 3,564

Block/head material: aluminum/aluminum

Bore × stroke (mm): 94.0 × 85.6

Horsepower (SAE net): 304 @ 6,400 rpm

Torque: 273 lb.-ft. (370 Nm) @ 5,200 rpm

Specific output: 84 hp/L

Compression ratio: 11.3:1

Assembly site: Flint, Michigan

Application tested: Cadillac CTS

EPA fuel economy, city/highway (mpg): 17/26

General Motors Corp.

6.0L OHV V-8 Hybrid

Look out the window and check to see if pigs are flying. That's what we figured would happen before any 3-ton GMC Yukon SUV achieved 20 mpg (11.8 L/100 km) in city driving.

Yet that's the powertrain near-miracle delivered by General Motors Corp.'s all-new 2-Mode hybrid-electric system, essentially an electronic continuously variable transmission (CVT) augmented by two electric motors, fixed-gear capability and a highly optimized, 6.0L variant of GM's small-block V-8. The breakthrough, of course, is that city economy of 20 mpg - 21 mpg (11.2 L/100 km) for 2-wheel- drive models - is a 50% leap over the same vehicle powered only by a 5.3L V-8.

GM boasts the Yukon Hybrid is as efficient in city driving as a 4-cyl. Toyota Camry. The company long has said it believes hybrid-electric vehicle technology, initially at least, is best suited for the industry's thirstiest vehicles, where the efficiency enhancement makes the most impact. The 2-Mode design, in fact, is an extension of the system first developed for mass-transit buses.

The automotive 2-Mode system was developed in cooperation with the former DaimlerChrysler AG and BMW AG. Chrysler LLC, Daimler and BMW also plan soon to release hybrid models using the 2-Mode design.

But it's GM that gets to market first with the GMC Yukon Hybrid, along with the same setup for Chevrolet's Tahoe fullsize SUV.

And this is no mere feel-good public-relations effort: The 2-Mode system is the first to bring hybridization to the fullsize utility-vehicle segment, and the technology has big implications for smaller, unibody platforms, too.

And for those who want to make the hybrid statement but still need the option to tow as much as 6,200 lbs. (2,812 kg), there is no other vehicle in the market.

The Yukon Hybrid's fuel-economy figures seem realistic, too - a problem prior hybrid technology has been forced to overcome.

Several Ward's 10 Best Engines testers achieved mixed-driving averages of 19 mpg (12.4 L/100 km) or so. That's pretty impressive for such a heavy vehicle being hauled by a 332-hp V-8. And everyone praises the fine integration of the 6.0L V-8 and the CVT 2-Mode.

“None of the annoying jerk-and-pull of typical hybrid transitions,” says one editor. “Enough electronic sophistication for a mission to Mars,” says another. And every judge awarded maximum points for technical relevance, saying this easily is the most technically significant powertrain introduced this year.

OK, we're not blown away by the roughly 10% fuel-economy improvement in highway driving. Early information had hyped the 2-Mode's advantages over “conventional” HEVs that deliver virtually no improvement in highway-driving efficiency. We frankly were hoping for more.

And no matter how you spin it, this system isn't cheap: The buy-in point is an eye-popping $50,490 for a 2WD Chevy Tahoe and tops out at $53,755 base price for a 4-wheel-drive Yukon Hybrid.

Even so, insiders say the company isn't recovering the full cost of 2-Mode.

Caveats aside, GM's 2-Mode system is a significant engineering achievement that has potential to propel hybrid technology to a new level of public and industry acceptance.

ENGINE SPECS

Engine type: 6.0L OHV 90° V-8

Displacement (cc): 5,967

Block/head material: aluminum/aluminum

Bore × stroke (mm): 101.6 × 92.0

Horsepower (SAE net): 332 @ 5,100 rpm

Torque: 367 lb.-ft. (498 Nm) @ 4,100 rpm

Specific output: 55 hp/L

Compression ratio: 10.8:1

Electric motor/transmission: (2) 60-kW electric motors/ 300-volt NiMH battery pack (30 hp electric boost)

Assembly site (engine/transmission): Silao, Mexico/ Baltimore, Maryland

Application tested: GMC Yukon Hybrid 4WD

Fuel economy, city/highway (mpg): 20/20

JUDGE'S PERSPECTIVE: It's a Gut Feeling

Purist engineers cast a skeptical gaze at the process we editors apply to the Ward's 10 Best Engines competition - unless, of course, their teams leave our awards event with a sparkling new showpiece for the office.

They ask questions such as, “How do you validate the horsepower number?” and “How do you separate the engine from the rest of the drivetrain?”

Those are valid questions, and our answers befuddle engineers who need to quantify everything they know and why they know it. They expect our 10 Best Engines testing data to fit conveniently in some matrix that makes perfect sense to Mr. Spock.

Truth is, our idea of a “matrix” consists of a large grid that ranks each engine based on score sheets for every vehicle evaluated.

And those evaluations are more subjective than objective because they are not done on dynamometers or in anechoic chambers with microphones positioned to capture the slightest errant noise.

No, 10 Best Engines judges experience the test vehicles in their routine daily driving cycles, and there's a good reason for that: Drive the same roads to and from work every day, and a great engine will make an impression at predictable times - on a long on-ramp to a metropolitan interstate, or on a 2-lane road with little traffic, where the only noise comes from combustion events under the hood.

A 10 Best Engines winner begs to be flogged in these situations, and occasionally we oblige. Of course, we do our best to pay heed to speed limits and practice safe driving.

It isn't necessary to run a vehicle at Autobahn speeds to decide if an engine is great. Take a vehicle to 45 mph (72 km/h) in second gear (with a manual transmission or an automatic with manual shift mode), and the flaws of a weak engine become apparent as it wheezes for breath, screeches in protest and fails to motivate.

Likewise, exploring third gear on the highway uncorks a broad power band in a great engine and exposes the limitations of the pretenders.

And don't underestimate the importance of a smooth idle. Sound damping today is so extensive that just about every vehicle sounds like a bank vault inside. And sometimes today's ultra quiet cars can unwittingly showcase flaws under the hood.

Every sound from the engine bay falls under the microscope of the human ear - from the passage of air through the induction system to the gentle ticking of the valvetrain to the steady rotational rhythm of the crankcase.

A poorly packaged engine allows vibrations to be felt through the gear shifter at idle or through the accelerator pedal when tipping in to the throttle.

We award points for power and torque and NVH (noise, vibration and harshness) - as we perceive them in our daily driving cycle. Yes, we look at specs, but what appears on paper does not always push our buttons.

An engine might make hellacious power, but if it's unbridled and rude, it won't make the list.

Likewise, if an engine that feels more powerful than the numbers on the spec sheet and illustrates superb powertrain integration (such as the normally aspirated 3.0L I-6 in the BMW Z4), it gets a closer look.

It doesn't take that long for each editor to decide whether an engine has the makings of a winner. It's a feeling in the gut, and you'd be shocked at how many engines have made our list year after year based on consensus.

Oh sure, we sit in a conference room and duke it out over which of the top 15 make it into the final 10, but every year there is much more agreement than discord.

People don't buy vehicles based solely on horsepower numbers and torque charts and the composition of an engine block. We take the same approach in crafting our 10 Best Engines list.
— Tom Murphy

Honda Motor Co. Ltd.

3.5L SOHC V-6

As much as everyone respects Honda Motor Co. Ltd.'s engine-development abilities, the company hasn't won that many 10 Best Engines awards.

We figure it's due to Honda's overwhelmingly conservative philosophy. While it's always stretching the boundaries of engineering, its production engines tend to be comparatively unassuming in specification.

Translated more directly: For a decade or more, Honda has deployed some of the most intelligent powertrain technology in the business, while resisting the horsepower and displacement escalation that is so much a part of the U.S. market.

It is the only one of Japan's three major auto makers that has refused to develop a V-8 for production. Thus, where a competitor uses a V-8, Honda has a V-6; often, it pits a 4-cyl. against a sea of competitors running V-6s, even in highly competitive segments.

So the latest 3.5L SOHC V-6, winning a 10 Best Engines award for the first time, goes somewhat against Honda's grain. The jump for the all-new '08 Accord is from the longstanding 3.0L V-6 to an extra half-liter of displacement. It is the largest engine ever fitted in a Honda passenger car.

But the uncharacteristic displacement bloat doesn't affect Honda's signature refinement. “No unpleasant vibration or noise,” says Executive Editor Tom Murphy. “I think Nissan's VQ (V-6, a perennial 10 Best Engines winner) has met its match.”

And several judges comment on the new 3.5L V-6's smoothness, also a Honda watchword.

Along with the refinement there's a stout 268-hp rating that's backed by outstanding flexibility in almost all speed ranges. The power is about what was expected of premium-vehicle V-6s just a couple of years ago.

This engine also gets a boost in efficiency when coupled with the 5-speed automatic transmission: Honda's Variable Cylinder Management (VCM) cylinder-deactivation system enables the V-6 to operate on three, four or six cylinders, depending on engine load.

This is combined with the expected VTEC (Variable valve Timing and Lift Electronic Control) wizardry fitted to all Honda engines. The VCM system also is abetted by active engine mounts and a unique active noise cancellation system that helps to mask the hiccups and transitions of 3- and 4-cyl. operation.

Accord coupes fitted with the new 3.5L SOHC V-6 and the 6-speed manual dispense with the VCM and the accompanying noise- and vibration-cancelling hardware and run with the more-conventional 2-phase VTEC that delivers that same unmistakable and luscious howl when the valvetrain switches to high-rpm mode.

This new 3.5L V-6 is the embodiment of Honda virtues: refinement and efficiency combined with performance that exceeds the hard numbers. Honda's new V-6 now challenges Nissan's stellar VQ as the best volume-market V-6.

ENGINE SPECS

Engine type: 3.5L SOHC 60° V-6

Displacement (cc): 3,471

Block/head material: aluminum/aluminum

Bore × stroke (mm): 89.0 × 93.0

Horsepower (SAE net): 268 @ 6,200 rpm

Torque: 248 lb.-ft. (336 Nm) @ 5,000 rpm

Specific output: 77 hp/L

Compression ratio: 10.0:1

Assembly site: Anna, Ohio

Application tested: Honda Accord EX-L Coupe (6-speed manual)

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

Mazda Motor Corp.

DISI 2.3L Turbocharged DOHC I-4

It's hard for us to believe 2008 marks the third 10 Best Engines appearance for Mazda Motor Corp.'s sparkling DISI 2.3L 4-cyl.

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.

We think this engine is the poster child for how affordable horsepower has become. Three years ago, there wasn't really anything even close to generating 114 hp per liter at the Mazdaspeed3's price point of $22,935.

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 fresh 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.

Best Engines testers still consider Mazda's DISI 4-cyl. the best of the breed, however. Like the GM 4-cyl., it has gasoline direct injection (GDI to us, Direct Injection Spark Ignition, or DISI, to Mazda), which is a supreme advantage for small-displacement turbocharged engines.

GDI is a low-rpm torque enhancer, the perfect companion for turbochargers, which need a few seconds at low rpm to really start generating their power-hiking huff.

And with twin balance shafts and beefed-up internals, this power-dense version of the Mazda-developed global MZR 4-cyl. architecture (also used by one-third owner Ford Motor Co.) is more refined than either of its direct competitors.

We were disturbed to see the Mazdaspeed6, the company's other performance model to use this engine, dropped for '08.

But if the front-drive Mazdaspeed3 is too much edgy overload (specially developed engine-management software does a so-so job of quelling torque steer), this engine does stellar duty in the CX-7 crossover, which uses all-wheel-drive to take torque steer to the woodshed.

Mazda's DISI 2.3L turbocharged DOHC I-4 is a whole lotta power, a whole lotta technology and a whole lotta fun at a fantastic price - a formula for success that makes Mazda one of the best little powertrain developers in the world.

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

JUDGE'S PERSPECTIVE: Mercedes Bluetec Blends Performance, Fuel Economy

Hybrid-electric vehicles are the poster children for environmental stewardship, but in reality, there are much better choices out there.

Take the Mercedes-Benz E320 Bluetec - a car with an engine that allows you to have your cake and eat it, too.

Yes, HEVs get decent fuel economy, but real-world numbers generally have failed to match those advertised. And let's face it, HEVs aren't all that much fun to drive.

The remarkable 3.0L V-6 turbodiesel in the E320 produces a staggering 400 lb.-ft. (542 Nm) of torque with silky smooth delivery.

Admittedly, the Bluetec's 210 hp won't impress many, but output numbers can be deceiving. When the rubber grabs the pavement, the gobs of torque clearly show this engine is no softy.

Diesel chatter is nearly imperceptible. And during mixed city and highway driving, we averaged more than 30 mpg (7.8 L/100 km), which is much better than the mileage achieved in the Lexus GS 450h hybrid luxury sedan. A tender-footed test drive of that vehicle yielded a mere 24.4 mpg (9.6 L/100 km).

Mercedes-Benz says the engine provides the “powerful torque of a large V-8 engine with the low fuel consumption of a 4-cyl. compact.” That may sound like a trite sales pitch, but in this rare case it's true.

Perhaps the greatest attribute of the Bluetec engine is its price - only $1,000 over the equivalent gasoline-engine E350. Compared with HEVs, where the premium is often in the thousands of dollars, the price vs. performance equation is overwhelmingly in favor of the Bluetec.

Its greatest contribution to the automotive world may be its potential to sway attitudes of U.S. drivers about diesels. No longer are they smelly, smoky and obnoxiously loud. Thanks to some thoroughly impressive technical breakthroughs, diesels such as the Bluetec are odorless, clean and quiet.

The Bluetec returns to the 10 Best Engines list after winning over last year's judges.

Next year, we expect to evaluate several new light-duty diesel applications slated for the U.S. For the first time ever, the 10 Best Engines list in 2009 could include more than one diesel.

Even so, I'll be rooting for the Bluetec.
— Byron Pope

Nissan Motor Co. Ltd.

3.7L DOHC “VQ” V-6

By now, Nissan Motor Co. Ltd.'s all-conquering VQ V-6 architecture needs no introduction.

The 3.7L variant's 2008 10 Best Engines award marks the 14th consecutive win for the VQ, and it is the only engine to win every year of the competition's history.

The VQ “brand” was established in 1995 on the pillars of landmark refinement and ultra-low noise, vibration and harshness levels.

Like many rivals, however, Nissan has not resisted the temptation to increase displacement, and over the years it grew into three distinct iterations: the original and oh-so-smooth 3.0L, the 3.5L introduced in 2002 (and still powering the majority of models from Nissan and its premium Infiniti brand) and the new 3.7L DOHC V-6 (VQ37VHR), which wins the 10 Best Engines award for 2008 and for now is available exclusively in the '08 Infiniti G37 Coupe.

In the quest for punchier power and torque numbers, the move to 3.5L was, to our senses, a tradeoff that peeled back on the VQ's signature refinement. But when the company's engineers unleashed the HR (High Rev) generation last year, many of the design changes - a structural ladder frame in the block, larger crank journals and asymmetric piston skirts, to name a few - had the tertiary effect of improving NVH while enabling higher, more satisfying engine speeds.

Now the stroked 3.7L variant of the VQ's HR design enjoys the same, only moreso. Our favorite: the sweet sting of 330 hp, a power improvement of almost 10% compared with the VQ35HR.

A little perspective helps, too. The latest VQ V-6's 330 hp is 30 horses stronger than Ford Motor Co.'s standard 4.6L Mustang V-8.

A prime goal was permitting engine speeds even higher than the 3.5L HR variant. Here, Nissan's octane-crazed engineers didn't mess around. The hair-raising new redline of 7,500 rpm is effortlessly and smartly accessed with almost no adverse auditory or tactile sensations.

Nissan says about 35% of the parts are unique to the 3.7L VQ, and the major new addition is the electronically adjusted variable valve lift (Variable Valve Event and Lift), imparting a “throttleless” effect not unlike BMW AG's Valvetronic, which also markedly reduces pumping losses by essentially throttling the engine with the intake valves.

Even with the efficiency claims for VVEL, we believe fuel economy, at 17 mpg (13.8 L/100 km) in the city and 26 mpg (9 L/100 km) on the highway, is hardly encouraging, and is one of our few complaints about the 3.7L DOHC V-6.

But this latest 3.7L variant of Nissan's special VQ V-6 may be the best in 14 years and is a magnificently focused engineering effort.

ENGINE SPECS

Engine type: 3.7L DOHC 60° V-6

Displacement (cc): 3,696

Block/head material: aluminum/aluminum

Bore × stroke (mm): 95.5 × 86.0

Horsepower (SAE net): 330 @ 7,000 rpm

Torque: 270 lb.-ft. (366 Nm) @ 5,200 rpm

Specific output: 89 hp/L

Compression ratio: 11.0:1

Assembly site: Iwaki, Japan

Application tested: Infiniti G37 Sport (6-speed manual)

EPA Fuel economy, city/highway (mpg): 17/26

Toyota Motor Corp.

3.5L DOHC V-6

All right: V-8 challenging power and torque. Supreme refinement delivered the old-time Toyota Motor Corp. way. And an innovative fuel-injection layout that still has some competitors asking why they didn't think of it.

Or, perhaps, “How could we ever afford that?”

This, too, is part of the Lexus mystique - how Toyota's premium division can continue to deliver top-shelf engineering and manufacturing for virtually every component, from hood release to fuel injector to trunk latch, yet remain price competitive.

All these aspects, and many more, make Toyota's 3.5L DOHC V-6 a unique and singularly satisfying engine experience.

We continue to call it the thinking man's V-6.

As it earns its third consecutive 10 Best Engines award, Associate Editor Byron Pope sums up the Lexus-exclusive engine's execution: “Good luck beating this in any category.”

In the titillating IS 350 sport sedan, the 306 hp and 277 lb.-ft. (376 Nm) say “V-8,” yet there are just six cylinders.

The signature design feat is the world's first fuel-injection system that uses both direct (in-cylinder) injection and conventional port injection. (The new Lexus IS-F V-8 also has it.)

Toyota claims choosing between the two - or blending their actions - generates optimum power, torque, emissions and fuel economy.

That all happens (well, we'd argue a bit about fuel economy), and Lexus assumes you already know about its legendary refinement.

But where the IS 350 application really nudges the needle is that engineers seem to have deliberately let a little more emotion edge out the near-clinical refinement.

“Sounds fabulous when pushed,” says Editor Drew Winter, and all judges agree this unquestionably is Lexus' most emotive engine.

That may be the most important marker set by Lexus' scintillating 3.5L DOHC V-6 as the company experiments with the formula.

If Lexus is able to combine its laboratory-grade levels of noise, vibration and harshness with the correct proportions of emotion that excite car junkies, even BMW needs to take heed.

Sure, there's still a vague, paint-by-the-numbers feel during casual driving - as if somehow robots had more to do with it than humans.

But smash the throttle one time and rollick to 60 mph (97 km/h) in 5.6 seconds, and you won't find anything digital in the experience.

As we're beginning to see more and more with Lexus, digital they've got down; understanding of the joys of analog is quickly being acquired.

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): 18/25

JUDGE'S PERSPECTIVE: Dear SRT4: It's not you. It's me.

Being a WARD'S 10 Best Engines judge is like being that guy on ABC's “The Bachelor.”

(Yes, I admit watching a few episodes. My daughter hid the remote, OK?)

On the show, this mimbo dates a different woman every night, gushes to each how he could spend his life with her and then gives roses to his favorites.

When he runs out of roses, he stands there like a dork - face to tear-streaked face with the women he spurned (usually toothy kindergarten teachers to whom he professed undying love 24 hours earlier).

Substitute the women for cars and you know how it feels to be a 10 Best Engines judge.

Too many engines, not enough roses.

For me, one of the toughest goodbyes was reserved for the Dodge Caliber SRT4's turbocharged I-4. I mean, what's not to adore about 285 hp that can inflict nearly 1G of lateral force for less than $23,000?

With its hair-trigger throttle and buzz-bomb exhaust note, this lively engine not only enhances the car - a key judging criterion - it delivers on the promise of Chrysler's World Engine.

Developed with Mitsubishi Motors Corp. and Hyundai Motor Co. Ltd., this high-volume architecture boasts advanced features such as variable valve timing for both intake and exhaust valves. But its tepid acceleration and lack of refinement left judges wanting last year.

Enter the engineers at Chrysler LLC's Street and Racing Technology division, who performed a masterful makeover with an emphasis on heat management. They devised a specially machined aluminum block and cross-drilled cylinder head to optimize flow, while stuffing iron cylinder liners with unique cast pistons cooled by oil squirters.

Tack on the Mitsubishi TD04 turbocharger and huge 11-row intercooler, and the SRT4's I-4 is a shining example of creative design.

So, why didn't it get a rose? I just couldn't see myself in a meaningful relationship with something so, forgive me, thrashy.

Flamboyant, over-the-top behavior is part of this engine's charm, for sure. But if I have to spend time in a high-revving turbocharged 4-banger, I prefer the company of the Mazdaspeed3's mill.

It's all about degrees of refinement. But that's just me.
— Eric Mayne

Ward's 10 Best Engines Nominees: Callin' It Like We See It

AUDI AG

BMW AG

CHRYSLER LLC

DAIMLER AG

FORD MOTOR CO.

GENERAL MOTORS CORP.

HONDA MOTOR CO. LTD.

MAZDA MOTOR CORP.

MITSUBISHI MOTORS CORP.

NISSAN MOTOR CO. LTD.

PORSCHE AG

FUJI HEAVY INDUSTRIES LTD.

TOYOTA MOTOR CORP.

VOLVO CARS

VOLKSWAGEN AG