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New Hellraiser 3.17 pulley adds power to your Hellcat or Demon without a tune

by Patrick Rall on

The Dodge cars (and Jeep SUV) powered by the supercharged 6.2-liter Hemi are among the most powerful production cars in the world, with output varying from 707 horsepower in the original Hellcat cars and SUVs to 840 in the Demon, with the Redeye delivering 797 horsepower while newer Hellcat models pack 717 horsepower. In stock form, these are some of the strongest street-legal engines in the world, but what makes them all really special is how easily owners can add gobs more power. Hellcat Hemis have been built to well over a thousand horsepower by many owners, but while it is relatively simple to add some people to your supercharged Hemi, it is not cheap.

Like many other companies, Dodge uses an encrypted engine computer system, so before you can apply an aftermarket tune, you have to either pay to have your PCM unlocked, or you need to buy an unlocked PCM and have it programmed to work in your car. Depending on how you go about getting an unlocked PCM, it can cost you upwards of $1,000, then you have to pay for the tuning device and the custom tune itself.

For example, if you bought the Hellraiser decoupling pulley that we talked about last October, you can gain over 130 horsepower at the rear wheels, but in addition to buying the $666 pulley, you also have to buy the unlocked PCM, the tuning device and the tune, so installing that $666 pulley ends up costing over $2,000 in the parts needed to make it all work.

However, with the new Hellraiser 3.17 pulley, Litens has come up with a way to add boost and power to your Hellcat, Redeye, Demon and Trackhawk without the unlocked PCM or even a tune. That’s right – if you have a Hellcat Hemi-powered Dodge or Jeep, you can bolt up the new Litens Hellraiser 3.17 pulley and pick up at least 25 wheel horsepower on 93 octane pump gas without touching the engine computer.

How It Works

In every modern engine, the computerized engine control system is constantly adjusting the parameters to optimize output. This allows the vehicle to offer comparable performance in all types of weather conditions and with varying quality of fuel, but the folks at Litens found out that the stock engine computer for the Hellcat Hemi will adapt to slightly more boost. The stock Hellcat pulley is 3.35 inches, so when swapping to a smaller pulley, such as the Litens 2.72 or 2.85 Hellraiser, you get more boost and more power, but the boost levels of those two pulleys requires an engine tune. On the other hand, the 3.17 pulley only adds between 1 and 2 pounds of boost, and the stock Hellcat Hemi engine computer can adjust enough to make use of that without an aftermarket tune.

Basically, if you install this 3.17 pulley from Litens, your Hellcat Challenger, Hellcat Charger, Redeye, Demon or Trackhawk will literally tune itself to accommodate for the extra boost and it will do so without touching the engine computer, the injectors or anything else under the hood.

Of course, like the other Litens Hellraiser pulleys, this 3.17 unit features the same stock-style decoupling system as the pulley that comes on the Hellcat Hemi, which reduces wear and tear on the supercharger.

Power Gains

While all of the testing on every model hasn’t been completed, there has been extensive testing done on a Demon with impressive results. When running on 93 octane pump gas, a 2018 Challenger Demon with this Litens 3.17 pulley picked up around 45 wheel horsepower and when that same Demon was running on MS109 race gas, it gained 70 rear wheel horsepower. On a standard Hellcat, the testing has shown gains upwards of 25 rear wheel horsepower on 93 octane pump gas, and those numbers should be relatively similar for the Challenger and Charger, while the all-wheel-drive Jeep Trackhawk may see slightly lower gains since it is spinning all four wheels. As for the Redeye, we don’t have official numbers just yet, but they should be similar to the Demon on pump gas, perhaps slightly lower.

In other words, if you drive a Hellcat Challenger, Hellcat Charger or Jeep Trackhawk, the Litens 3.17 Hellraiser pulley can add around 25 wheel horsepower without a tune or the cost of an unlocked PCM. In a Challenger Redeye or Demon, expect closer to 45 rear wheel horsepower on pump gas and Demon owners can pick up 70 at the wheels when running on race gas – again, all of this without an aftermarket tune.

So, if you want to add between 25 and 70 rear wheel horsepower in your supercharged Dodge or Jeep and you want to avoid the cost of an unlocked PCM and aftermarket tune, the Litens 3.17 Hellraiser might be the perfect winter upgrade for your Mopar machine.


The 3.17 Hellraiser isn’t available yet on the Litens website, but with a belt, the install tool and the end cap, this pulley has an MSRP of $899, with prices varying a bit from those aftermarket retailers who are currently offering this easy upgrade package.

Patrick Rall was raised a Mopar boy, spending years racing a Dodge Mirada while working his way through college. After spending a few years post-college in the tax accounting field, Patrick made the jump to the world of journalism and his work has been published in magazines and websites around the world.

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