BY LARRY WEBSTER, PHOTOGRAPHY BY JEFFREY G. RUSSELL
A six that runs like an eight.
With its revamped V-6 engine now making 302 horsepower, Cadillac seems to be making the case that the optional V-8 is no longer necessary.
This latest V-6 is indeed a gem. Significant among its attributes is direct fuel injection, which squirts the fuel into the combustion chamber rather than the intake track. That’s not new technology, but direct injection is gaining in popularity because when the fuel is introduced into the cylinder, there’s a cooling effect that increases charge density and reduces the tendency for harmful detonation. This allows designers to raise the compression ratio for better efficiency and more power.
The compression ratio for this GM V-6, which is only in the 2008 STS for now, is 11.3:1 (compared with 10.2:1 in last year’s V-6). With variable intake- and exhaust-valve timing, power surges to 302 horsepower from 254 and the torque is 272 pound-feet, up from 252. Huge gains, considering the V-6’s displacement remains at 3.6 liters.
It’ll take a finely calibrated backside to feel the difference between the new STS V-6 and the optional 320-hp V-8 model, which last year came bundled with several features and as a result cost about $9500 more. The two now share the same six-speed automatic transmission, and the acceleration times are within a few ticks of each other. The V-6 scoots to 60 mph in 6.2 seconds, behind the V-8 by only 0.2 second.
With this punchier V-6, Cadillac has seen fit to offer the performance handling package that used to be available only with the V-8. It includes a stiffer suspension, Brembo brakes, special wheels with summer tires, and retuned steering gear. The handling package should cost about $1600. Unless you want the four-wheel-drive STS, which doesn’t offer the handling package, don’t skip this option”equipped with it, the STS absorbs potholes and frost heaves with the right level of firmness, and if the stability-control system is shut off, the car will drift its tail on request.
Cadillac has made detail improvements that include a shifter which no longer feels as though it belonged in a Cavalier. Pricing was not set at press time, but figure $43,500 for a base V-6, and think hard about spending extra for the V-8.
2008 Cadillac STS V-6 Spec
VEHICLE TYPE: front-engine, rear-wheel-drive, 5-passenger, 4-door sedan
ESTIMATED PRICE AS TESTED: $56,000 (estimated base price: $43,500)
ENGINE TYPE: DOHC 24-valve V-6, aluminum block and heads, direct fuel injection
Displacement: 217 cu in, 3564cc
Power (SAE net): 302 bhp @ 6300 rpm
Torque (SAE net): 272 lb-ft @ 5200 rpm
TRANSMISSION: 6-speed automatic with manumatic shifting
DIMENSIONS:
Wheelbase: 116.4 in
Length: 196.3 in
Width: 72.6 in
Height: 57.6 in
Curb weight: 4100 lb
C/D TEST RESULTS:
Zero to 60 mph: 6.2 sec
Zero to 100 mph: 15.7 sec
Zero to 130 mph: 31.1 sec
Street start, 5“60 mph: 6.7 sec
Standing ¼-mile: 14.7 sec @ 97 mph
Top speed (governor limited): 141 mph
Braking, 70“0 mph: 159 ft
Roadholding, 300-ft-dia skidpad: 0.86 g
FUEL ECONOMY:
2008 EPA city driving (C/D est): 16 mpg
C/D-observed: 16 mpg
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