Quote from the Allpar story:
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.