2006 Cadillac STS in Joliet

Ann Arbor- Push the starter button to the right of the Cadillac STS-V's steering wheel, and the supercharged V-8 leaps to life while the driver-information LED display briefly illuminates the greeting, "Ready for STS-V?" After spending a week with the most powerful Cadillac ever produced, we'd like to throw that question back at Cadillac, and at GM: Are you ready for STS-V? Is Cadillac, which has been scratching and clawing its way back to respectability, really prepared to go head-to-head with AMG-tuned Mercedes-Benzes and M-badged BMWs? Or is the STS-V, like the CTS-V, a noble, competent, and entertaining effort that ultimately is compromised by unattended details?

If it is, it's certainly not for a lack of V-series enthusiasm among GM engineers, who giddily describe the modifications they've made to the base STS to arrive at the STS-V. The most important of these changes, of course, is the new, supercharged, 4.4-liter version of the Northstar V-8, which produces 469 hp and 439 lb-ft of torque, increases of 149 hp and 124 lb-ft over the normally aspirated 4.6-liter V-8.

Development of Cadillac's first supercharged production engine extended beyond simply nestling the Roots-type blower between the V-8's 90-degree cylinder banks. To fortify the Northstar for this assignment, the cylinder bores were reduced from 93 to 91 millimeters, which resulted in the smaller displacement, and the engine block is sand-cast rather than die-cast, for a 40 percent improvement in fatigue strength. New cylinder heads, heavy-duty pistons, revised connecting rods, and a lower compression ratio-9.1:1 versus 10.5:1-also help accommodate the additional output.... Read full article