2015 Dodge Challenger SRT Hellcat is most powerful muscle car ever
The 2015 Dodge Challenger SRT Hellcat, the most powerful muscle car ever, now boasts a fuel-economy rating as compelling as the 707 horses hurrying from its 6.2-liter supercharged HEMI® Hellcat V-8.
Equipped with Chrysler Group’s segment-exclusive TorqueFlite eight-speed automatic transmission, the new Challenger SRT Hellcat has earned a highway fuel-economy rating of 22 miles per gallon (mpg) from the U.S. Environmental Protection Agency (EPA).
The Challenger SRT Hellcat carves a unique place for itself in the lofty world of high-performance driving. Consider the price, output and 2015 EPA highway fuel-economy ratings of the following:
• Lamborghini Aventador Roadster – $425,845; 700 horsepower; 18 mpg
• Aston Marton Vanquish – $287,820; 576 horsepower; 18 mpg
• Mercedes-Benz SLS AMG GT – $221,580; 583 horsepower; 19 mpg
The supercharged 6.2-liter HEMI Hellcat benefits from content that is 91 percent new, compared with its 6.4-liter SRT cousin, better known as the 392 HEMI.
Engineered in-house, the Hellcat engine is designed for optimum durability in the face of the enormous loads that accompany its prodigious power. Its forged-steel crankshaft has induction-hardened bearing surfaces that contribute to its capacity to withstand firing pressures of 1,595 psi (110 bar) – the equivalent of five sedans standing on each piston, every two revolutions.
The HEMI Hellcat further benefits from premium-grade, heat-treated aluminum-alloy cylinder heads that are optimized for thermal conductivity. These are topped by a twin-screw 2,380-cc/rev supercharger that features integral charge coolers and an integrated electronic bypass to regulate boost pressure to a maximum of 80 kPa (11.6 psi).
A separate low-temperature cooling circuit with two air/coolant heat exchangers integrated into the supercharger housing keeps air temperatures below 140 degrees Fahrenheit (60 degrees Celsius), while enabling air flow of up to 30,000 liters per minute.
So effective is this feature that engine power will not be de-rated due to cooling demands, even after 20 minutes of hard driving on a road course at an ambient temperature of 100 degrees Fahrenheit (37 degrees Celsius).
The HEMI Hellcat does not lack for style, either. Its die-cast aluminum rocker covers echo the block’s Street HEMI Orange motif.
The car’s new TorqueFlite eight-speed automatic transmission boasts maximum engine-torque capacity that is 30 percent greater than any eight-speed previously offered by Chrysler Group. To ensure its responsiveness matches the demanding expectations of SRT customers, the transmission features one additional pinion gear in each of the 1st and 3rd gear sets, and five more clutch-pack disks – two in clutch E and one each in clutches A, C and D.
The defining benefit of the gearbox is its 7.03 ratio spread, which enables the powerful HEMI Hellcat to operate in its most efficient mode, more frequently.
Not to be outdone, the Challenger SRT Hellcat earns an EPA highway fuel-economy 21 mpg when equipped with its new-for-2015 six-speed manual transmission. The sporty gearbox boasts an internal cooling pump and external, vehicle-mounted oil cooler and its beefier 258-mm heavy-duty clutch affords easy access to HEMI Hellcat’s prodigious power.
Source: Dodge & Chrysler Group.
