Dodge Challenger: Mopar's Modern Muscle Car
What you get when you combine a modern rear-drive sedan with reruns of That '70s Show.
Work on the Challenger began at Chrysler's recently closed Pacifica Design facility in California in 2004, just as Ford was introducing the current generation Mustang. Fresh off the success of the Chrysler 300, the LX base was modified to accept a very 1970s-esque two-door body as part of a "top hat" strategy that places new sheetmetal over a lightly revised lower structure. However, this process saddled the Challenger with the very thing that makes the LX a fine four-door sedan: size and bulk. As a result, Dodge,s modern muscle car has a 116-in. wheelbase, is 197.7-in. long overall, sits 57.1-in. high, and is 75.7-in. wide. Compared to Ford,s Mustang (107.1-in. wheelbase, 187.6-in. overall, 55.4-in. tall, and 73.9-in. wide), the Challenger is a big car, and-except for the 4.0-in. shorter wheelbase and 1.4-in. lower height-it is even bigger than the 300. Also, at 3,720 lb., the Challenger is approximately 600 lb. heavier than the Mustang.
Forget the anemic 2.7-liter V6 that powers the base Chrysler 300. The Challenger SE is powered by a 3.5-liter, single overhead cam, 24-valve V6 mated to a very 1980s four-speed overdrive automatic transmission (a manual is not offered on the SE). Power output is 250 hp @ 6,400 rpm and 250 lb-ft @ 3,800 rpm, and this combo propels the car from 0 to 60 mph in 7.8 seconds while returning 18 mpg city/25 mph highway. The Challenger R/T is powered by a revised 5.7-liter Hemi V8 capable of 372 hp @ 5,200 rpm and 401 lb-ft @ 4,400 rpm when mated to Chrysler,s very 1990s A580 five-speed overdrive automatic. Choose the Tremec TR6060 six-speed manual, however, and this rises to 376 hp @ 5,150 and 410 lb-ft @ 4,300 rpm. "We added variable valve timing to the 5.7-liter, increased the compression ratio from 9.6:1 to 10.5:1, and extended the range of the MDS [multi-displacement system] on the automatic-equipped cars," says Chris Nowak, lead engineer on the Challenger. These changes increased fuel economy by an average of four percent (it's rated 16 city/23 highway with the automatic, and 15/23 with the manual), added 30 hp, and increased torque across the engine speed range by up to 20 lb-ft. "But the big news is the manual gearbox," says Nowak. "It's the first time one,s been hooked up to the new generation Hemi."
The TR-6060 is a variant of the transmission found on the Dodge Viper. It uses a 250-mm Sachs dual-disc clutch to reduce inertia and engagement force, triple-cone synchronizers on the first two gears, dual-cone synchronizers on the other four, and revised gear ratios to meet both fuel economy and performance targets. Hill Start Assist, though not technically part of the transmission, holds brake pressure for three seconds to allow a clean clutch engagement on inclines. The TR-6060 is shared with the most powerful Challenger, the SRT8, which debuted with an automatic in 2008. Its 6.1-liter Hemi puts out 425 hp @ 6,200 rpm and 420 lb-ft @ 4,800 rpm, and has a deep-skirt cast-iron block with cross-bolted main bearing caps, aluminum heads, and no variable valve timing. Standard issue is a 226-mm Getrag-supplied limited-slip differential in a lightweight aluminum die-cast housing that features three carbon clutch packs on either side of the differential to send torque where it's needed. In the future this could be upgraded to include torque vectoring.
Like the Chrysler 300 from which they came, each Challenger has a short-long arm front suspension with a high upper A-arm, gas-charged coil-over shock units, an anti-roll bar, and lateral and diagonal lower links. The very 21st century independent rear suspension is a five-link design with coil springs, a link-type anti-roll bar, and gas-charged twin-tube shocks mounted on an isolated cradle. However, the SRT8 replaces the standard shocks with Bilstein monotube units, adds different bushings, and is not as harsh as expected. "If you place the 300 SRT8 on one end of a line and the Charger SRT8 on the other," says Tom McCarthy, senior manager, SRT Engineering, "the Challenger would be near the Charger, but not as extreme." That,s because customers felt the Charger was unforgiving, a feel that would have been easy to replicate with the Challenger SRT8,s standard low-profile tires (P245/45ZR20 front and P255/45ZR20 rear on fully-forged Alcoa aluminum wheels). McCarthy admits he and his team "have looked at Delphi,s magnetorheological damper units" to mitigate harshness while increasing performance, but are sticking with the Bilstein units for now.
Each version has four-wheel disc brakes, and ABS, traction control with brake assist, and stability control are standard on all but the SE. It also has the smallest brakes, 12.6-in. vented front and solid rear discs with single-piston sliding aluminum calipers. R/Ts have 13.6-in. front and 12.6-in. rear vented discs with dual-piston sliding aluminum front calipers, and the SRT8 get 14.2-in. front and 13.8-in. rear vented discs clamped by four-piston Brembo calipers with fixed aluminum housings. In addition, the SRT8,s brakes have pad knockback mitigation software that, according to Kip Owen, director, SRT Engineering, "was developed from the pad-wiping software that dries off the brake pads when they get wet." New code keeps the brake pads from being knocked back into the caliper under hard cornering. That, in turn, not only gives a faster response and shorter braking distances, but also better brake feel in hard use. Given the car's capabilities-0-100-0 mph in 16.8 seconds and a top speed of 170 mph-it's a useful addition.
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