GMC 4.5L V8 Duramax Diesel

Mark your calendars, because we're calling today a watershed moment for the advancement of diesel's acceptance in the U.S. General Motors has just announced a new 4.5L V8 Duramax turbo-diesel powerplant it plans to use in the Chevy Silverado and GMC Sierra half-ton pickups, as well as the HUMMER H2. The new oil burner is expected to produce at least 310 horsepower and 520 ft-lbs. of torque. It features dual-overhead cams, four valves per cylinder, a variable-vane turbocharger and aluminum cylinder heads with integrated manifolding that helps keep the overall package small enough to fit in the same space as the automaker's small-block gas V8s.

That's right, just imagine the possibilities. Wherever GM uses a small-block V8 gas engine, it could potentially use the 4.5L V8 Duramax diesel. In a few years we could be driving diesel Impalas, diesel Camaros, maybe even a diesel Corvette! To quote GM's press release, the engine's small size gives it "the flexibility to introduce this engine in a wide variety of vehicle applications should there be future market demand." Indeed.

GM estimates that the engine will improve fuel efficiency by 25%, reduce CO2 emissions by 13% and decrease particulate and NOx emissions by at least 90% in its GMT900 pickups and the HUMMER H2. Whoever said the HUMMER H2 was on its way out will likely be proven incorrect after this engine debuts. Scheduled to be built at the GM Tonawanda engine plant outside Buffalo, NY, the 4.5L V8 Duramax diesel will be 50-state emissions compliant and meet 2010 diesel emissions standards, as well. GM claims its new diesel will also have NVH (Noise, Vibration and Harshness) levels approaching those of today's current gas V8s, though we'll have to wait and see if that wish comes true. That wait should end in a couple of years, as the automaker states the engine will be available in Silverado, Sierra and H2 models built after 2009.

2007 Chevrolet Impala Review

The Chevrolet Impala is a comfortable and convenient car, practical and enjoyable to drive. We find its neat, clean lines pleasing to the eye. Its styling looks fresh and it is. The Chevrolet Impala benefits from its recent redesign for 2006.

Several upgrades and refinements for 2007 make for a better car: The available 3.9-liter V6 gets GM's Active Fuel Management system, which idles cylinders at certain times for improved fuel economy. A tire-pressure monitor comes standard. OnStar comes standard and has been upgraded for 2007, offering the new Turn-by-Turn navigation service. And OnStar will automatically communicate the nature and severity of a crash as well as its location to the 911 centers.

The Chevrolet Impala is a big car. It's generally classified as a mid-size sedan, though it's large for that class, and nearly a full-size. The front and back seats are roomy, though not inordinately so given the size of this car, and getting in and out of the car is easy. and it has a healthy cargo capacity. It has a huge trunk and flip-and-fold back seats that present holding wells for groceries or a flat cargo floor that expands the trunk for long items.

It's very stable on the open road, a nice cruiser. There's lots of low-end torque from the larger of the two available V6 engines, the 3.9-liter V6. Step on the gas and it goes. And it handles well, in fact surprisingly well given its size.

Several models are available, ranging from strong, reliable, fuel-efficient family sedan to sleek and powerful performance car. The mid-level Chevrolet Impala LT probably best exemplifies the model line. We like the LT with the optional 3.9-liter V6 engine, which gets GM's Active Fuel Management system for 2007, which improves real-world fuel economy. The LTZ adds leather and other convenience features. The SS comes with a small-block 5.3-liter V8 engine that sounds great and delivers strong acceleration performance.

For its low price alone, the Chevrolet Impala will be on many family-sedan shopping lists, where it competes against the Ford Five Hundred, Chrysler 300, Dodge Charger, Honda Accord, Toyota Camry, and Nissan Altima.

2007 Vortech Corvette Z06

The Corvette C6 Z06 clubs nearly everything in its path. With 505 horsepower produced from a hand-assembled 7.0-liter LS7 V-8, the Z06 easily outpaces the mighty 8.3-liter Viper SRT-10 Coupe-which has made the Dodge boys quite angry. In response, SRT will soon release its super-strength 2008 Viper shod with a new 8.4-liter V-10 that cranks out 600 hellspawned horses. The gloves are off and the fight is on.

Rather than being outgunned by Mopar, Corvette Z06 owners can now gear up with more power thanks to a booster shot of bolt-on performance from Vortech Engineering. Known for making big top-end power, Vortech produces a variety of centrifugal superchargers that cram heaping helpings of added oxygen into an engine for impressive power gains. In the case of the new Corvette Z06, Vortech has just put the final touches on a kit featuring its latest V-2 SQ T-trim centrifugal supercharger, which delivers 6 psi of boost to the LS7 V-8. The SQ design stands for "Super Quiet." Gone is the obnoxiously loud gear whine associated with most centrifugal superchargers. Rather, at idle and cruise speeds, the blower is nearly silent-so as not to give away your forced-induction secret.

The Vortech kit ($6695, satin finish; $6995, polished finish) offers everything needed for installation, including a T-trim supercharger, air-to-air aluminum intercooler, compressor bypass valve, aluminum mounting brackets and hardware, high-flow fuel pump, oversize fuel injectors, and even a specially programmed Diablo Sports handheld programmer to reflash the factory computer with the proper spark/fuel calibrations. The result is an LS7 engine that cranks out a dyno-proven 635 horses (35 more than the upcoming 8.4-liter Viper's), while sipping 91-octane pump fuel. In addition, the 50-state smog-legal kit is optionally available with a three-year/36,000-mile powertrain warranty through Vortech's network of top-tier installers and new-car dealers.

Enough tech talk, how does the Vortech kit perform? The answer is simple: too well. Fit to a bone-stock Corvette Z06 (tires, exhaust, suspension, etc.), the output is so substantial the car has a hard time taking off. Laughable amounts of rear tirespin occur in first gear, even with part throttle application. In fact, our best quarter-mile launch resulted when bogging the V-8 off the line at 1400 rpm and then short-shifting the 1-2 shift at 4400 rpm-before big boost hit. In second gear, the stock Goodyear Eagle F1 325/30ZR19 tires puts down thick black stripes on the tarmac as the Corvette Z06 fishtails wildly. By third gear, you can apply full throttle, wind to the 7000-rpm redline, then watch the speedometer digits count up faster than a Chinese mathematician working a nitrous-fed abacus.

At the end of the quarter mile, the Vortech Z06 runs just a few tenths quicker than a stock Corvette Z06 (due to wild tirespin), but delivers a nearly 10 mph more trap speed (a more accurate indicator of the power increase). With stickier tires, a Vortech-blown Z06 should run in the 10s. Rejoice knowing a Vortech Z06, even with copious tirespin, will still go 0 to 100 to 0 mph in a scant 11.7 seconds. Take that, Mr. 8.4-liter Viper.

Chevrolet Camaro Convertible Concept

Of course! A convertible! It's as obvious as the response General Motors expected last year when it posed the question, "Should we build a new Camaro?" in three glorious, 1:1-scale Detroit-show dimensions.

Look at the Camaro coupe concept's top, or the original 1969 Camaro to which it pays homage, and you'll see it's easy to slice it off without compensating for too fast a fastback. It's easy if you picture it or photoshop it as we did months ago. It wasn't as easy for Tom Peters, director of rear-drive design and chief of design for the Camaro convertible, last year's coupe, and, not coincidentally, for the C6 Corvette.

"It's amazing how many people think that's all you do," Peters says. "Probably every surface is changed, say, two or three inches down from the door-cut back all around. Even the spoiler looks like the one on the coupe, but it's not."

Rear fenderlines drop off from the horizontal surface to the vertical surface a couple inches farther out than on the coupe to keep proportions good. If showing a Camaro convertible concept at the 2007 Detroit show seems obvious, that's only from your armchair.

It may not be so obvious as it is necessary. Chevy will launch the Camaro coupe in late 2008 as a 2009 model; then to battle the other Ford Mustang body style, it'll launch the Camaro convertible about spring of 2009. We're still awaiting official word from Chrysler on a ragtop version of the 2009 Dodge Challenger, but that's another no-brainer.

"The overall car statement is," Peters says, "whereas the last one was pure, design-statement, performance-oriented, this one has more of a fun, sporty, kind of personality to it. And that's appropriate. That's what Camaro's been in the past; that's what these types of cars have been in the past. Sporty, fun, and all the way to the serious performance."

As the concept makes the rounds of car shows following its Detroit debut, GM Australia is hard at work on the production car. Expect thicker sills and tunnels and added cross-bracing to give the convertible's unibody coupelike stiffness.

Doing another Camaro concept also gave Peters's crew the chance to work on different colors and textures. The convertible concept has charcoal SS stripes over a lustrous Hugger orange paint job-the stripes are so dark they appear black under certain light. You might think of the 1969 Camaro RS/SS Indy 500 official pace car, which has orange stripes on a white body.