Thought the Dodge Hellcat models had an impressive engine? The Challenger SRT Demon turns it up to the max.
When Dodge revealed the Challenger SRT Demon in 2017 ahead of its launch for the following model year, it was every drag racer’s dream crammed into a production car.
Fitted with a wider body, street-legal drag tires, the first transbrake fitted to a production car, a line-lock system, and even more beyond that, it’s one mean drag strip-ready machine.
While there’s a lot to talk about with the Demon, it’s the big engine lurking under its scooped hood that we wanted to take a look at and let you know everything about it.
A derivative of the Hellcat Hemi V8, it’s unsurprisingly a total powerhouse, but with it offering upwards of 100 hp more, there are plenty of changes to talk about.
So, strap yourself in as we run you through everything you need to know about the Dodge Demon engine – from its technical specifications and the performance it delivers, to any reliability and maintenance concerns you may have if you’re looking to add to your garage one of the 3,300 examples of the Demon that were produced.
Dodge Demon: Technical Specifications
The 6.2-liter supercharged V8 found in the Dodge Demon features the same basic block design as the engine found in the SRT Hellcat, Trackhawk, and TRX models.
An overhead valve (OHV) engine like all Chrysler Hemi V8s, this SRT-specific version features the 4.09 in bore of the larger 6.4-liter version, but the shorter 3.58 in stroke of the 5.7-liter variant, equating to 376 cu in (6,166cc). The block itself is made of cast iron while the cylinder heads are aluminum alloy, and the engine has a 9.5:1 compression ratio and a redline of 6,500 rpm.
Numerous unique changes were made to the Demon engine to help it deliver an even higher level of performance, however.
A larger 2.7-liter IHI twin-screw supercharger that produces 14.5 psi of boost is one of the most notable performance upgrades, while many of the engine internals such as the forged pistons, connecting rods, and crankshaft have been upgraded to handle the extra power.
As with all modern third-generation Chrysler Hemi engines, its combustion chamber is no longer truly hemispherical as it was in earlier units, with it not only being a flatter design but a more complex one as well.
To reduce emissions and allow for more consistent combustion, it features a coil-on-plug dual ignition system that utilizes two spark plugs per cylinder. Multiport fuel injection is still utilized, rather than direct injection, but variable camshaft timing does play an important part.
Dodge Demon: Performance Figures
When it comes to the Demon engine, the numbers are undoubtedly the most impressive thing. Running on Premium 91 octane gas, it produces 808 hp @ 6,300 rpm and 717 lb.-ft. @ 4,500 rpm – enough power to ensure its place as the most powerful engine fitted to an American production car.
However, if a mere 808 hp wasn’t enough for you, you could always install the new ECU that was included with the “Demon Crate” and given to all buyers of a 2018 Challenger SRT Demon when new – it also included tools and various other specialized performance parts.
The extra boost really unlocks this engine’s full potential. Now, allowing it to run on 100 octane fuel, like running it on race gas, turns those numbers up to a hefty 840 hp and 770 lb.-ft.
With this much power – combined with all the other drag-focused performance upgrades – it made the Demon capable of some truly impressive numbers. Dodge claims a 0-60 mph time of a mere 2.3 seconds. As a reference to how close the claim is to reality, Road & Track was able to achieve a verified 2.6-second sprint.
Its massive power was enough to get the Demon banned from competition by the National Hot Rod Association due to the lack of a roll cage in a sub-10 second car.
It’s also worth mentioning that similar versions of this engine – with slightly lower power outputs and without 100 octane fuel compatibility – are still currently fitted to Challenger and Charger SRT Hellcat Redeye (797 hp), and the Challenger SRT Super Stock (807 hp).
Dodge Demon: Reliability & Maintenance
Thanks to a long-term ownership report by Kelley Blue Book, the reliability and durability of the Demon has been well-proven. Over the course of a year and 4,000 miles – which included 60 quarter-mile passes – KBB had no reliability issues with the Demon’s engine, with the only unscheduled dealership visit being due to the new powertrain control module (PCM) included in the Demon Crate which allows the full 840 hp to be unleashed not being installed correctly, although it should be noted that it was originally fitted by the publication’s staff, rather than a dealership as recommended.
The only other engine-related expenses KBB encountered were oil changes, which cost the publication $110 each. The Demon is fitted with an oil change indicator light that will alert the owner of when an engine oil change is required, but Dodge does note in the Challenger SRT owners manual that the service interval should not exceed six months or 6,000 miles, whichever comes first.
Pennzoil Ultra Platinum 0W-40 is the factory-recommended oil for all 6.2-liter supercharged engines including the Demon engine, and both the oil pan and oil cooler must be drained when performing an oil change on this engine. This engine uses full-flow disposable oil filters, with a Mopar filter being recommended.
While few issues with the Demon engine itself have been reported beyond the odd forum post, some engine electrical issues have been reported and recalls were issued in 2018 for the PCM due to issues with the cruise control system not canceling, and voltage regulator potentially causing the vehicle to stall.
Crate Engine Availability
The Demon may have been the only production model to have ever received this engine (with 808/840 hp maximum outputs on 91 and 100 octane fuel respectively), the version of this engine fitted to the 2021 Challenger SRT Super Stock that develops 807 hp on 91 octane fuel is available as a crate engine from Mopar as the Hellcrate Redeye for the princely sum of $21,807, and is designed specifically to be fitted to pre-1976 Dodge models.
Dodge Demon Engine: A Muscle Car Icon
Firmly cementing its place as the most powerful V8 engine ever fitted not just to a muscle car but indeed any American car, the 808 hp-plus Demon engine is a truly iconic piece of machinery that will no doubt go down as one of the greatest V8s in history.
Powerful and reliable, it’s clearly a very good unit that delivers truly staggering performance figures in the 2018 Challenger SRT Demon it was exclusively fitted to. If you’re looking at picking up one of the 3,300 examples of this read-legal drag racer for yourself, make sure you run a VIN check first for peace of mind to ensure any required recall work has been done and that there’s no undisclosed accident history as well.
Photos: Deposit Photos
