2015 Dodge Challenger SRT: muscle cars with Hellcat supercharged V8s
On May 20, 2014, Dodge officially unveiled its supercharged Hellcat engine and the 2015 Dodge Challenger SRT twins — one with the 392, the other with the supercharged 6.2 Hemi. Either V-8 engine can be mated with a six-speed manual transmission or a beefy new TorqueFlite eight-speed automatic.
On July 1, 2014, the 100th anniversary of the founding of Dodge Brothers, the horsepower and torque ratings of the new Hemi engine were released: 707 hp and 650 lb-ft, the latter near the upper limits of the eight-speed automatic transmission.
On July 11, Dodge released official NHRA quarter-mile times of 11.2 @ 125 mph on stock tires, and 10.8 @ 126 mph on drag slicks.
The 392 engine power has been upgraded from 470 to 485 horsepower, with torque climbing from 470 to 475 lb-ft. Fuel economy is 14/23 for the manual, 15/23 for the automatic — a mere 1 mpg gain (city only) for the automatic, over the 2014 models with their five-speed automatics.
The Hellcat’s stunning 707 horsepower, 650 lb-ft of torque, roughly matches Allpar predictions, though we believed the horsepower rating would “approach” 700 and that torque would be around 640 lb-ft.
The supercharged engine uses a forged-steel crankshaft with induction-hardened bearing surfaces, which can withstand firing pressures of 110 bar (1,595 psi) – the equivalent of five family sedans standing on each piston, every two revolutions. Its unique crank damper has been tested to 13,000 rpm. Sodium-cooled exhaust valves use hollow-stem construction and steel-alloy heads that stand up to temperatures as high as 1,472° Fahrenheit (800° Celsius). Cam profiles afford 14.25-mm inlet and 14.0 mm of exhaust lift.
High-strength, forged-alloy pistons, developed using telemetry measurement, are coupled to powder-forged connecting rods with diamond-like-carbon-coated piston pins. The supercharged 6.2-liter Hemi V-8 has heat-treated aluminum-alloy cylinder heads optimized for thermal conductivity, with Hemi Orange die-cast aluminum rocker covers.
Hellcat-equipped cars will come with two key fobs, red and black; the red key fob unlocks the full horsepower and torque of the Challenger SRT Hellcat engine, while the black fob limits engine output to 500 horsepower (as predicted by Allpar a month before the announcement).
Valet Mode, standard with both Challenger SRT engines, makes the following changes:
- Power output is cut, and engine speed is limited to 4,000 rpm
- Access to first gear is locked out, and the transmission upshifts early; it treats the “manual override” position as “Drive”
- Paddle shifters are disabled
- Drive Mode is set to “Street” with no override
- Electronic Stability Control (ESC) is enabled to Full-on
- Launch Control is disabled
Drive Modes control horsepower, transmission shift speeds, steering (Challenger SRT only — not Hellcat), paddle shifters, traction, and suspension. Drive Modes are pre-configured for Sport, Track and Default settings, with a Custom setting as well. Sport provides better performance; Track provides maximum performance on smooth, dry surfaces.
The Drive Mode feature is controlled through the Uconnect system and may be accessed by pushing the SRT button on the instrument panel, from the “SRT & Apps” menu on the touch screen, or from the Performance Pages.
The 2015 Dodge Challenger SRT rides on new, SRT-exclusive “77” eight-spoke 20 x 9-inch forged-aluminum black wheels. Standard 245/45ZR20 Goodyear RSA2 All-Season or available Goodyear F1 Supercar Three-Season tires deliver serious grip and handling.
Standard wheels on the Challenger SRT with the Hellcat engine are new “Slingshot” split-seven spoke 20 x 9.5-inch, lightweight forged-aluminum wheels with a matte black finish (also used on the SRT 392 as part of the SRT Track Pack). Available on the Challenger SRT Hellcat are 20 x 9.5-inch, lightweight forged-aluminum wheels with a Brass Monkey/dark bronze finish.
New P275/40ZR20 Pirelli P Zero Nero tires (front and rear) provide all-season traction, while Pirelli P Zero tires are available for three-season performance driving.
The SRT with Hellcat has the largest front-brake package ever offered in an SRT vehicle, with 390-mm (15.4-inch) Brembo two-piece rotors with six-piston calipers; this is also available on the 392 HEMI® SRT model as part of the SRT Track Pack. New anti-lock braking system (ABS), ESC and traction control systems are configurable for specific tire and powertrain configurations.
A larger, power-bulge aluminum hood features a dedicated “cold-air” intake – a visual styling cue from the first Viper coupe built in 1996. The Hellcat hood includes dual air extractors to remove heat and cut air turbulence in the engine bay; it is standard in body color and is available in Satin Black. Both Challenger SRTs have aluminum hoods to reduce weight. The Challenger SRT Hellcat also has an Air Catcher inlet port, which rams air directly into the engine air box through the driver-side parking lamp.
Integrated projector fog lamps on the Challenger 392 SRT are pushed to the lower corners to help accentuate the car’s width. A new duck-bill fascia splitter helps improve aerodynamics. The Hellcat has a larger front splitter for optimal downforce, and “SUPERCHARGED” fender badges. Black sills were tuned in the wind tunnel. A unique, taller rear spoiler on the SRT Hellcat features a raised SRT logo.
Many of the most memorable paint colors in automotive history have been found on the Challenger. Both SRT Challengers will be available in B5 Blue, Billet Silver Metallic, Bright White, Granite Crystal Metallic Pearl, Ivory White Tri-Coat Pearl, Jazz Blue Pearl, Phantom Black Tri-Coat Pearl, Pitch Black, Redline Tri-Coat Pearl, Sublime Metallic Pearl, and TorRed. Twin, full-body stripes are available in black gloss and silver gloss on the SRT 392.
Much of the 2015 Dodge Challenger SRT’s interior is shared with the standard models; designer Ryan Nagode wrote, “Challenger SRT's uniqueness is found in our color and material palletes including Laguna leather, unique cluster appearances and 7" TFT imagery, SRT Drive Mode control screens, and ‘Engine Turn’ stamped-aluminum instrument panel and console bezels.”
The new instrument panel has a stamped aluminum bezel; a 7-inch configurable display is centered in the gauge cluster, with new analog gauges on either side, drawn from the “tic-toc-tach” 1971 designs. With the Hellcat, the gauges and graphics are both finished in a dark Radar Red tone. New for 2015, drivers can select a background for the 8.4 inch touch-screen.
The aluminum trim gets one of two finishes, “Hectic Mesh” for the Challenger 392 SRT and “Dark Engine Turn” for the Challenger SRT Hellcat. The center console houses redundant button and knob controls for the audio and climate system; a new media hub with an SD card slot, USB outlet, and audio jack is inside the center console’s armrest.
The TorqueFlite eight-speed automatic transmission has a new electronic shifter with a driver-oriented T-handle for intuitive gear selection, and an Auto Stick selector gate. The track-proven Tremec TR6060 six-speed manual transmission has a throwback ball shifter.
A redesigned SRT-branded heated steering wheel has a flat bottom and available paddle shifters (with automatic transmission). This new tilt-telescoping steering wheel also has a 360-degree heat element. Seat comfort has also been improved, and ventilated/heated front seats are standard. The passenger seat has an easy exit/entry system for rear seat access. Seats are covered in Nappa leather/Alcantara material with embroidered SRT logo, with Laguna leather, either sepia or black with embossed SRT logos, available as part of an equipment package.
Production is scheduled to begin in the third quarter of 2014, with ordering to begin in the summer.
A new M-gate shifter and steering-wheel-mounted paddles better connect driver and transmission; there are nearly 200 possible drive-mode combinations from the distinct settings (default, sport, track, valet, and custom). Launch Control is standard, and enhanced by stiffer, asymmetric half-shafts that minimize “power hop” under hard acceleration, and a new driveshaft with high-strength CV joints; both driveshafts and half-shafts have new lubricants for higher-speed operation.
The Tremec TR-6060 manual transmission has a 240 mm twin-disc ZF-Sachs clutch with the 392, a 258 mm version of the same clutch with the Hellcat. Both have a triple cone (1, 2)/double cone (3-6) synchronizer design, with 1-4 skip-shift and reverse-inhibit solenoids and a 5:1 remote shifter. The differential is asymmetric-limited slip on all Challenger SRTs.
A new, 230-mm rear axle was needed for the higher torque; the new axle is more efficient, with a lightweight aluminum housing, cooling fins, high efficiency bearings, and low-viscosity fluid. Durability measures include welded ring gears, shot-peened gear material, hardened shims, four-opinion differential, and four-point mounting.
An asymmetric limited-slip differential allows for unique bias-ratio tuning for on- and off-throttle behavior. This enhances grip, stability, and steering response, for hard acceleration on corner exits. When trail-braking, the differential further tightens to stabilize the car and prevent oversteer.
SRT powertrain chief Chris Cowland wrote that they specified “the ability to complete 20 minutes of full-speed track driving in extreme ambient temperatures without the need for cooling-system-driven derate. This places significant burden on the cooling capacity of the vehicle.”
Supercharger and engine details
The exhaust note was custom-engineered using an electronically controlled exhaust valve; the first time a 2015 Dodge Challenger SRT Hellcat was fired up on the assembly line in Ontario, workers came running to investigate. The 2.75-inch, straight-through, twin-exhaust system includes durable, double-walled exhaust manifolds and ceramic catalysts capable of withstanding temperatures up to 1,922° Fahrenheit (1,050° Celsius).
Real-time performance information is shown on the customizable gauge screen or the 8.4-inch touchscreen; it can now also be saved to a USB or uploaded online to the Mopar’s Owner Connect page.
Drivers using their voice to launch the app will be greeted with the Dodge SRT Performance Pages. When they push the Timer button on the touchscreen, they’re connected to the “reaction time” feature, which gives the driver a 2.5-second countdown. From there, they can access screens with:
- Timers: Top speed, 0-60 mph acceleration, 0-100 mph acceleration, elapsed times for one-eighth mile and one-quarter mile distances, reaction time for launching against a simulated drag strip timer, and lap time (a new timer that allows drivers to record lap times on the gauge cluster). The system can also show braking distance in feet or from the speed at which brakes were applied. All timers can be shown with current, best, or last.
- Gauges: Two pages of gauges show oil temperature, oil pressure, battery voltage output, coolant temperature, intake air temperature, and transmission oil temperature.
- G-Force: Real-time lateral G-force measures left and right (turning) force, while longitudinal G-force shows the acceleration and braking force; peak shows the maximum g-forces that have been achieved.
- Engine: Speed, real-time horsepower and torque, oil pressure, boost (Hellcat only), and gear-selector position (automatic transmission cars only).
|Electrical||220 amp alternator; 730 CCA, H7 type battery|
|Suspension||Front: Independent short-long-arm, coil spring over ADS Bilstein shocks and hollow stabilizer bar and lateral and diagonal lower links. Rear: Five-link with coil springs, link-type hollow stabilizer bar, ADS Bilstein shocks, and isolated suspension cradle.|
|Brake assist||8 + 9 (203 + 209) tandem-diaphragm vacuum booster; brake knockback mitigation included|
|Hellcat 6.2||6.4 (392) Hemi|
|Turning diameter||38.5 feet||37.5 feet|
|Front stabilizer bar||34 mm||32 mm|
|Rear stabilizer bar||22 mm||19 mm|
|Track||64.0 front, 63.7 rear||63.4 front, 63.1 rear|
|Frontal area||25.9 square feet||25.6|
|Hellcat 6.2||6.4 (392) Hemi|
|Weight (lb)||4,439 automatic, 4,449 manual; 57/43 front/rear||4,251 auto, 4,240 manual; 55/45 F/R|
|Front rotors||15.4 x 1.34 two-piece aluminum hat, vented, slotted||14.2 x 1.26 vented, slotted|
|Front calipers||1.42 (36 mm) Brembo six-piston fixed monoblock, 424 square inches swept area||1.73 (44 mm) Brembo four-piston fixed, with 351 sq inch swept area|
|Rear brakes||13.8 x 1.10 vented and slotted rotors, 1.26” (32 m) four-piston fixed calipers, 316 sq-in swept area|
For interior specifications, see 2015 Dodge Challenger.
Allpar first reported on a supercharged 6.2 Hemi coming down the line on June 18, 2012. At that time our sources were predicting 700 horsepower, and based on experience with such predictions, we assumed it would end up at around 580-600. Eventually, as more news came in, we bumped that estimate up to 640-680 horsepower, but since it will be paired with an eight-speed automatic (in Dodge Charger and as an option in Dodge Challenger SRT), we also assumed torque would be limited to 640 lb-ft of torque.
Allpar’s predictions of the Hellcat logo and dual power levels have both been shown to be correct. Thank you, oh2o and other sources!
Challengers by year
|1970-74 • 2008-10 • 2011-14 • 2011-14 SRT • 2015 Challenger • 2015 SRT • Specs/Models • 2015 Pricing|
|Special Challengers • Police cars • V10 Drag Pack • Super Stock Pack • 2013 R/T Redline • Scat Pack • Mopar ’14 and Shaker|
|426 Hemi • 318, 340, 360 • 383, 440 • New Hemi • SRT V8 • 3.6 V6 • 5-spd • 8-spd|
|2010 R/T Stick • 2009 Challenger SE • 2009 SRT8 stick-shift • 2008 SRT8 automatic|
|Midnight Club game car • Vintage Challenger Forum • New Challenger Forum • 2016 Barracuda? • 2015 Videos|
Books: Barracuda and Challenger: 1964-74 Barracudas and 1970-74 Challengers, with production figures by model. Good visuals, vague text. ... Challenger & Barracuda Restoration Guide, 1967-1974 by Paul A. Herd (1997).