Petty's Garage Gains Over 126 RWHP With Mods to 2018 Demon

Bradley Sisson Mar 28 2018

The age old question in the hot rod world has always been: "Is there a such thing as enough horsepower?".  Quite frankly we believe the answer to that question is no, there will always be those that push the envelope and test the limits of what can be done under the hood.  This is not a curve we plan to stay behind, so naturally when Dodge released the 2018 Challenger Demon (which is basically a street legal drag car) we couldn't wait to get our hands on one and go to work.  

As you may have read in a previous blog post, The King was able to score #0043 off the line in a sinister all black paint scheme and once word got out we quickly found our first Demon owner turned Petty's Garage customer.  This Demon with a very clean look of White Knuckle sporting a matte black hood.  Before developing a build plan, we first put the stock Demon on our dyno to get a baseline rwhp number on pump gas.  

 After a few pulls, we saw an initial reading of a healthy 662.95 HP at the rear tires on pump gas, pretty unbelievable for a car coming straight off the showroom floor!  But as we all know, there is no such thing as enough power so our team got to work putting together a package that would improve airflow and fuel injection without having to change the stock supercharger or engine internals.

That package consists of an upgraded pulley kit, 72 lb injectors, Kooks Longtube Headers, Kooks 3" High-Flow Cats & Mid-pipes, Magnaflow Competition Series exhaust system, and unlocking the vehicle's PCM in order to write a custom tune making all of the new upgrades function properly with the car.  Our tuning department has become an industry leader with the ability to tune 2018 HEMIs, and has really pulled off a groundbreaking accomplishment with this Demon.

Back to the dyno!


After a number of pulls and tweaking of the tune, the Powered by Petty Demon put down 789.03 rwhp on pump gas.  A total gain of 126.08 HP!  This improvement is quite remarkable considering modification was little more than an upgraded pulley and exhaust with no changes to the stock supercharger or engine internals.  While many may see the Demon as a complete car ready for the strip, we say there is still plenty more to be desired.  Check out the video footage of the Demon's dyno run below.  If you are interested in upgraded horsepower to your Demon, or any modern muscle machine for that matter, give us a call at 336.495.6602 and let Petty's Garage make your automotive dreams a reality.


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