General Motors Corp. 2.8L Turbocharged DOHC V-6
By Bill Visnic WardsAuto.com, Jan 4, 2006 11:35 AM

The dominant engine layout in the U.S. is the V-6.

Last year, about 44% of the vehicles produced in North America came so equipped, and V-6s beat every other engine layout in terms of total sales.

Strangely, though, there are few V-6s using forced induction to generate big performance. In the U.S., if you want a V-6 with better performance, you buy a V-8.

So it is a special day to see an all-new turbocharged V-6.

General Motors Corp.'s 2.8L turbocharged DOHC V-6 – for now used exclusively by its Saab Cars division – has such an engaging all-around performance profile, we wonder why more auto makers do not take a chance on this rare and satisfying format.

For those expecting the super-sized specific-output numbers to which we have become accustomed with forced-induction 4-cyl. engines, this new turbocharged V-6 might appear tame at 89 hp per liter.

But the number surpasses the new wave of high-powered normally aspirated V-6s (Lexus 3.5L V-6 makes 87 hp per liter) that are almost a full liter larger, and it whips most V-8s by a healthy margin.

The low-ish torque figure of 258 lb.-ft. (350 Nm) betrays this engine's comparatively diminutive displacement. But what it lacks in ultimate thrust is compensated for by the delectable torque curve typical of a turbo engine: Every pound-foot of twist is at your disposal from just 2,000 rpm.

On the road, that translates into flexibility normally aspirated V-6s and V-8s cannot replicate.

Hold a gear longer than usual (the standard 6-speed manual is the better choice over the 6-speed automatic, incidentally), and the low-inertia, twin-impeller turbocharger makes haste to dial up maximum torque.

For midrange needs, meanwhile, the combination of six cylinders and turbocharging generates explosive shove.

We would put the Saab 9-3 Aero's in-gear acceleration up against anything in its class, or against anything a class or two above. There are few V-8 sport sedans, for instance, that can run away when the full turbocharged fury of this 2.8L V-6 is deployed.

This engine, based on GM's new “global” V-6 architecture, drastically upgrades the rusty 3L turbocharged V-6 Saab recently dropped from its 9-5 lineup. That engine produced just 200 hp and 229 lb.-ft. (310 Nm) of torque.

Although the new and much more powerful 2.8L V-6 currently is available only for the 9-3 model line, it can be assumed the new turbocharged V-6 will be fitted in the all-new replacement for Saab's 9-5 flagship due in a couple of years.

The GM 2.8L turbocharged DOHC V-6 is a unique and compelling addition to the U.S. powertrain scene. It is a convincing luxury performance engine that reinforces Saab's heritage for leading-edge turbocharged mills.

Judges' Comments

Winter: Just love the smoothness of this engine.

Banks: Polite and well-mannered. A sophisticated driving experience. A poor man's BMW 330i.

Visnic: Hang on for dear life when running to redline in 3rd or 4th gear. Throw in direct injection, and let's really party!

Engine type: 2.8L turbocharged DOHC 60° V-6

Displacement (cc): 2,792

Block/head material: aluminum/aluminum

Bore x stroke (mm): 89 x 74.8

Horsepower (SAE net): 250 @ 5,500 rpm

Torque: 258 lb.-ft. (350 Nm) @ 2,000-4,800 rpm

Specific output: 89 hp/L

Compression ratio: 10:1

Fuel economy for tested vehicle (EPA city/highway mpg): 18/28

Application tested: Saab 9-3 Aero

bvisnic@primediabusiness.com