Inside the 707HP Hellcat Hemi

Inside the 707HP Hellcat Hemi


Producing the highest horsepower production vehicle in automotive history can often times be a challenging prospect. And in achieving their goal, Dodge not only stole the thunder from their Detroit counterparts but reestablished themselves in the performance market. The all new Hellcat Hemi is a testament to this fact and it’s made a statement to the tune of 700 horsepower.

While most of the muscle car crowd eagerly anticipated the all-new 2015 Ford Mustang sport coupe or the new 2016 Chevy Camaro, were instead stunned with the Hellcat. Dodge truly has upped the ante at the table of high horsepower performance in factory form.

2015 Dodge Challenger SRT Hellcat


At the heart of the new Dodge Challenger is a few different HEMI enginees, starting with the 305hp 3.6L Pentastar V6, with an extremely impressive 30mpg EPA fuel rating. The 6.4L HEMI V8 is the next step up in power, with 485hp and 475 ft lbs on tap between a choice of six speed manual transmission or eight speed automatic.

Of course the true prize of the group is the Hellcat HEMI engine, a 6.2 liter supercharged monstrosity that bludgeons the opposition with a iron fist. This engine defies conventional marketing and defies logic as Dodge truly has created a engine that can both pound the pavement and outstanding reliability.

6.4-liter HEMI V-8 engine cutaway for Jeep Grand Cherokee SRT8

Dodge didn’t just slap a combination of parts together to build a haphazard horsepower machine, instead building from the oil pan up. The forged crankshaft uses a 3.58 stroke to produce the displacement of 370 cubic inches, and the 2.4 liter supercharger produces pressures close to 1,600 psi within the cylinder combustion chamber.


The shortblock is based on the 90 degree truck block found in the HD Ram pickup trucks. Dodge incorporated the new crankshaft and strengthened the bottom end to endure the high cylinder pressures the Hellcat would produce. According to chief engineer Gregg Black, an aluminum block was initially planned but scrapped due to excessive cylinder pressures.

“Were not saying aluminum was an impossibility,” explains Black “but the iron gives us the stiffness that helps prevent distortion under the high cylinder pressures.”

The Hellcat HEMI crank is held in place with induction hardened bearing surfaces, a first for any Chrysler production engine. Forged aluminum pistons and connecting rods deliver a forced induction friendly 9.5:1 compression ratio. The pistons have been graphite coated to prevent piston skirt issues and increasing durability.


The IHI based supercharger unit pushes 12 psi through the it’s twin screw helical rotors, compressing the incoming air charge. Feeding the engine through a gigantic 92mm throttle body, the Hellcat HEMI engine is built to withstand the punishment the supercharger can deliver. Air is drawn through the eight liter air ram intake system that is incorporated into the grille mounted air box.

Dodge also turned it’s attention to the fit and finish of the trim components as well as inside the cabin. Often criticized for the spartan interior and rowboat like exterior dimensions, Dodge has redeveloped the car with a new eye on style. The centerpiece of the interior redesign is the industry leading 8.4inch touchscreen monitor and Uconnect integrated media center.

Dodge’s 7-inch thin-film transistor (TFT) customizable driver information center, a redesigned electronic shifter, and over 70 new safety and security features including the push button starter, Forward Collision Warning, Adaptive Cruise Control, Blind-Spot Monitoring and Rear Cross Path Detection.

Check out the video from Power Automedia takes us inside the Hellcat with this Youtube video on a demonstration model of the Dodge powerplant.

Whether or not Dodge’s Hellcat Hemi succeeds in becoming the new gold standard for performance vehicles remains to be seen. But one thing is certain, the manufacturer horsepower wars are definitely back and we couldn’t be happier.

Happy boosting!