Wednesday, November 25, 2015

Cadillac CTS


A handsome car with the chassis BMW should have put under the 5-series.
Cadillac’s CTS fended off multiple Audis, Benzes, and BMWs to win its 10Best berth. While we are (still) big fans of the twin-turbocharged, 420-hp V-6 that powers the Vsport model, it’s the handling that sets the CTS apart from the competition. To determine how GM sharpened the CTS’s reflexes to cuff the Germans, we returned to the scene with Cadillac’s executive chief engineer, Dave Leone.
Turns out that Leone and his development team know these byways—located only 30 miles from GM’s proving grounds—as well as we do. “We’re here every month to check our progress tuning new models and to assess competitors,” Leone explains. “The bends, bumps, and abrupt elevation changes challenge any car’s integrity, so this loop is an excellent ­supplement to our Milford Road Course and Nürburgring work.”



The third-generation CTS builds on the ATS’s Alpha foundation with larger wheelbase and track dimensions. “To optimize mass efficiency and to achieve a [near] 50-50 weight distribution, we created over 40,000 analysis models. We specified aluminum for most of the front components, positioned the battery at the rear of the car, and counted every gram to gain a 200- to 300-pound weight advantage,” Leone adds. “We targeted both the E90 [2006–2013] BMW 3-series and the current 5-series. When the 5 got heavier, our task became easier.”

Leone’s strategic weapon, the electronically controlled magnetorheological (MR) dampers that GM developed years ago, has seen use in several sporty European cars. As we sail over a crest, he notes: “Our goal is maintaining the car’s composure in the face of severe road inputs. The MR dampers help keep the body straight and level by sensing suspension travel and by responding rapidly with extra rebound control over rises like this one. The dampers collaborate with the springs and anti-roll bars to keep the body flat in sweepers and to quell waddle [GM’s funny word for head toss] over undulating pavement.”

Encountering a stretch of tortured asphalt, Leone switches the Driver Mode Control from sport to tour. “The softer tour setting enhances comfort over rough roads while still providing enough damping to meet our goal of limiting wheel motion to one up-down cycle per bump,” he explains.

2015 10Best Cars: Cadillac CTS The body control is astounding over roads like this, but if the steering were less faithful, there’s a good chance we wouldn’t enjoy driving the CTS as much as we do. Leone explains, “Thanks to compliance in the belt connecting the assist motor to the steering rack, there’s minimal interference with the feedback traveling from the road to the driver’s hands.”

To Leone, the whole goal of chassis development is to create that elusive special sauce: “After enjoying a delicious dinner, you might ask for the recipe. That will reveal the ingredients while telling you nothing about the chef’s subtle contributions. The car-world equivalent is what we call integration: applying the necessary small refinements to assure that the whole vastly exceeds the sum of the parts.” And it’s amazing how General Motors—long the corporate behemoth most associated with sloppy handling, inattention to detail, and a generalized malaise—has gotten so adept at turning the good into the great.