2015 Chevrolet SS

The SS is the car Chevrolet wants NASCAR fans to cheer for on Sunday, then buy on Monday. Look closely at the Chevrolet-powered NASCAR entries and you’ll find the faux headlamp, tail lamp and grille stickers on the car resemble the SS.

It requires a certain suspension of disbelief to buy into the notion that the car has any OEM Chevrolet parts in it, but that’s essentially what NASCAR racing has become.

If those fans show up on Monday to test drive an SS, any disbelief flies out the window because the 2015 SS is convincing in street trim and a great American interpretation of a sport sedan. Well, an Americanized Australian-built interpretation of a sport sedan.

Manufactured in Elizabeth, South Australia, the SS is sold down under as the Holden Commodore, which V8 Supercar fans will recognize from that racing series. The difference between NASCAR and V8 Supercars is that the Aussie cars more closely resemble those in the showroom, but there is still relatively little in common with production models.

“The SS reinforces Chevrolet’s position as America’s performance-car brand, and affirms what we’ve believed all along – enthusiasts want the driving experience that only a rear-drive sedan can provide,” said Brian Sweeney, U.S. vice president, Chevrolet. “And by the way: BMW is the top non-GM-brand trade-in from SS customers.”

In production trim, the Chevrolet SS is available with either a six-speed Tremec TR6060 manual transmission or a six-speed automatic. For good or ill, the test vehicle at the Motor Press Guild’s Track Days program was fitted with the automatic. The nice thing about the SS, compared with other cars available for testing that day, was how easy it was to turn off all the nannies. Just push and hold the mode select button on the center console.

Either way, you get a 6.2-liter LS3 Vortec V8 that produces 415 horsepower at 5,900 rpm and 415 pound-feet of torque at 4,600 rpm. The nice thing about this engine is that it’s naturally aspirated, so the intense heat-soak of a supercharger is blissfully absent. That means the car won’t go into limp mode if you decide to take the SS out for a day of HPDE.

If you opt for the automatic, the rear axle ratio is 3.27:1. For manual cars, the rear axle ratio bumps up to 3.70:1. Whether you get the manual or automatic, fifth and sixth gears are overdriven, which helps explain 21-mpg highway EPA fuel economy rating for a 415-horsepower car. The SS is rated for 14 mpg city, but accelerator pedal makes the car so fun and responsive you’d be hard-pressed to get decent mileage around town.

The block and heads are cast aluminum, with cast iron cylinder bore liners. The 6.2-liter is fitted with two valves per cylinder, 10.7:1 compression, sequential fuel injection and “coil near” not “coil on” plug ignition. The engine revs smoothly and easily all the way to 6,600 rpm all while running on regular fuel. No pricey 91 octane required. All that power is good for a zero-to-60 mph time of 4.7 seconds. That’s quick for any car, let alone one that weighs 3,975 pounds.

If you do decide to take it to the track, the magnetic ride control provides more precise body motion control. According to Chevrolet, “The system uses electromagnetic coils that continually adjust damper fluid consistency every 10-15 milliseconds.” The SS’s new dual-coil damper system reacts 40 percent faster than last year’s system. It is standard equipment on the SS and it features driver-selectable tour, sport and performance modes.

Stopping power comes courtesy of standard Brembo bakes, with four-piston calipers, ventilated 14-inch discs up front and 14.2-inch rotors in the rear.

The handling of the SS is due in no small part to a nearly 50/50 weight distribution and low center of gravity. Chevrolet went so far as to use aluminum construction for the hood and rear deck lid to achieve that balance.

“This may be the sleeper car of the whole event,” said NASA Director of Business Development Jeremy Croiset, who drove the SS at Willow Springs International Raceway. “It’s got great balance toward understeer and still can hang the tail out on throttle. It’s also got good brakes, power and grip. The seats need more support and side bolstering, but I really liked this car for an HPDE/family ride.”