Dodge debuted the new 2015 Charger with refreshed sheet metal, updated cabin, and revised chassis, with a new top-of-the-range SRT Hellcat model serving as the new flagship of the line. The new sheet metal is significantly slipperier than before, with the new car embracing a more contemporary version of the snub-nosed blunt appearance of the outgoing Charger.
All 2015 Chargers benefit from a variety of upgrades, such as the eight-speed ZF automatic transmission, which is now standard across the line. The car also features new electric power steering with three driver-selectable effort levels and a cast aluminum rear axle housing and aluminum hood to trim weight.
There are LED taillights and front parking lights, while the inside sees the installation of more premium materials, a standard 7-in driver information display and new thick-rimmed steering wheels.
Three-mode Bilstein adaptive shock absorbers let drivers choose among auto, sport, and track settings on the Charger SRT models, the 392, the R/T Scat Pack, and the Hellcat.
The Charger SRT line for 2015 starts with the 392 and its 6.4-L Hemi V8. For this year the engine’s ratings grow to 485 hp (362 kW) and 475 lb·ft (644 N·m), increases of 15 hp (11 kW) and 5 lb·ft (7 N·m) from last year’s car. It rolls on new 20 x 9.5-in aluminum wheels that surround 15.4-in (391-mm) front brake rotors and six-piston Brembo front calipers. The rears are 13.8-in (351-mm) rotors and four-piston Brembos. Tires are Pirelli P Zeros, either all-season or three-season versions.
The Hellcat employs the same engine as covered previously here from the Challenger launch (http://articles.sae.org/13227/), but in the longer Charger, less drag permits an eye-opening top speed of 204 mph (328 km/h), while more advantageous weight distribution contributes to a quarter-mile acceleration time of 11.0 s. That means that, although the Hellcat has a unique speedometer that reads to 200 mph (322 km/h), the car is capable of running out of numbers on the gauge.
The Charger Hellcat eliminates the fog lights that are standard equipment on other Chargers, using those openings in its bumper fascia to duct air to an oil cooler and to a secondary heat exchanger for the supercharger’s intercooler. Additionally, the Hellcat’s aluminum hood is stamped with deep heat extractor vents on either side of the central NACA air intake duct.
These keep intake air temperature below 60°C (140°F) even during extreme ambient conditions and, as a result, the Hellcat’s power need not be dialed back even after 30 minutes of hard road-race course driving in 37°C (99°F) ambient temperatures.
Meanwhile, the Hellcat’s supercharged engine’s power meant that the ZF eight-speed automatic had to be upgraded to withstand the engine’s torque. This was accomplished by adding pinion gears to the first and third gear sets and by adding five more clutch pack discs. Each Hellcat transmission also sees an additional layer of quality testing after assembly. In the Track drive mode, the transmission executes 160-ms gear shifts.
Similarly, the differential is reinforced with welded ring gears, shot-peened gears, hardened shims, and then bolted in with a new four-bolt attachment. It drives through asymmetric axle shafts that are designed to minimize axle hop under acceleration.
In addition to drivetrain bolstering, Chrysler’s dynamometers also needed upgrading to handle the engine’s power during development, according to the company. During that development work, the engine ran the equivalent of nearly 2 million customer hours on the dyno, and one of the cars endured 100 consecutive quarter-mile drag strip runs. Furthermore, every new Hellcat engine runs for 42 min on a dyno before it is installed in a car to confirm all is well with the engine.
The Hellcat’s exhaust is appropriately industrial-strength, as befits such a powerful engine, with dual 2.75-in (70-mm) pipes feeding ceramic catalysts that are able to tolerate temperatures of 1050°C (1922°F). Bypass valves in the mufflers open the exhaust when the drive-mode system is set to Track, giving the Hellcat a suitably loud character when driven aggressively.Continue reading »