Slideshow: Inside the 6.2-Liter Madness That is the Demon
Nearly everyone knows of the Demon but how many of us know just what is going on under the hood of one? Get the low down on the fire and brimstone that is bubbling inside of this hellish vehicle.
Air induction and boost
Let's start out with what sets the Demon apart from the run of the mill Hellcat. The Hellcat's got a 2.4 supercharger tacked onto it while the Demon comes in with a 2.7-liter twin-screw supercharger. The maximum amount of boost in the Hellcat is just 11.6 while the Demon turns up the oven to 14.5 psi of power. On top of that, during a quarter mile at full throttle, the Demon's engine will swallow 173 cubic feet of air coming from the Air Grabber hood scoop, the third inlet near the driver-side wheel liners and the driver side headlamp. The induction system combined can flow 1,150 cubic ft of air per minute into the Demon all while still passing pesky noise level requirements.
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Fuel needs
The Demon had the honor of being the very first production car that was designed to run on deliciously sweet 100-octane gasoline. However, the car can still knock the sense out of other vehicles when it is running on 91 octane as the engine will still make 808 horsepower and 717 lb-ft of torque. 100 octane has the effect of Popeye eating some spinach with the Demon unleashing 840 horsepower and 770 lb-ft of torque, which will get you down a quarter mile in 9.65 seconds.
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The rotating assembly
The Demon is more than just a higher output Hellcat with a larger supercharger hooked up to it. The Engineers at Dodge changed or upgraded over 65% of the engine's compartment. The crankshaft, connecting rods, and pistons are all stronger than that of the Hellcats. The engine block was beefed up to give a 50% greater volume of oil to the piston oil squirters, and the connecting rods are were reinforced around the pin bosses. The piston-ring clearances and main bearings were both optimized for potential higher speeds and greater amounts of boost. In addition to that, high-tensile rod and main cap bolts were used with the engine block being torque plated honed before assembly.
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Valvetrain choo choo
So what were the engineers to do with an engine that produced 6,500 rpms? Well, they got in there and threw redesigned valves with single-groove keepers for greater stability at higher rpms. The oiling system delivers 30% more oil to the springs and an increase in the valve spring rate to keep them nice and cool at sustained high rpm operation.
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No need to pick another
When you are looking to purchase a Demon just know that there will only be one option for the transmission, the 8HP90. There is a version of this transmission in the Hellcat but this demonic variant gets several improvements including a higher-stall torque converter and the inclusion of a transbrake feature in the programming. When that feature gets activated, the transbrake will hold the driveline in place while the torque converter loads, thus allowing the engine to build up boost. When let go, the Demon is slingshotted through each gear at a speed in just 400 milliseconds so as to leave as little as possible interruptions in the flow of power.
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Drive line
Everything after the transmission has been strengthened to deal with the tremendous load that comes from a vehicle that is 4,250 pounds and can generate nearly 2 Gs of force from a standing start. The driveshaft is made of high-strength steel and sees a 20% jump in wall thickness over that of the Hellcats. The 41 spline axle shafts are also thicket and incorporate eight ball CV joints, while the ring and pinion and differential housing are all made with heat-treated alloys.
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