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Update on the 1000hp Forza Tuning Hellcat Challenger

The folks at Forza Tuning have rolled out the latest video showing their Dodge Challenger SRT Hellcat project car, complete with a stage 4 package that the company states will produce better than 1,000 horsepower at the crankshaft.

A few weeks back, we looked at the nasty 2015 Dodge Challenger SRT Hellcat being built by Forza Tuning in Georgetown, Indiana. The Forza team was working towards the 1,000 bulk horsepower mark and the company had produced a series of high quality videos showing the supercharged Challenger on the road and on the dyno during the various steps of the process. When we first talked about the Forza tuned Hellcat Challenger, the car was making 746 rear wheel horsepower with the stage 3 kit, but the last video back then ended by teasing stages 4 and 5.

Well, the team has completed the development of their in-house stage 4 kit for the 2015 Hellcat Challenger, and the results are impressive.

Forza Strives for 1,000hp
When we last checked out the Forza tuned Hellcat Challenger, it was making 746 rear wheel horsepower with the stage 3 kit, after stage 1 yielded 691 rear wheel horsepower and stage 2 made 733 rear wheel horsepower. Stage 1 added new spark plugs, a cooler thermostat, Amsoil 0W-40 Signature Series oil and a Forza in-house custom tune. Stage 2 added a 10% ATI overdrive crank pulley and Stage 3 adds headers and cat deletes, along with a new tune for each package.

Unfortunately, details are a little short at this point, but according to the Forza FB page, stage 4 includes “performance work on the blower” that I would expect was a porting or port-matching job – both of which would allow the supercharger to breathe a little easier. Stage 4 also includes a new pulley setup, but the company hasn’t elaborated on the stage 4 pulley changes.

With the Forza stage 4 package, this Dodge Challenger SRT Hellcat laid down an awesome 807 rear wheel horsepower and 740lb-ft of rear wheel torque. This same car made 654 horsepower and 609lb-ft of torque at the rear wheels on the Forza dyno when stock, so the stage 1-4 upgrade packages on the supercharger Hellcat Challenger have added 153 horsepower and 131lb-ft of torque at the wheels.

Big Power, Questionable Math
According to Forza Tuning, they are using an “industry standard” calculation of 20% drivetrain loss for the Hellcat Hemi, but if this exact car was losing 20% of the power between the engine and the wheels, the stock testing results of 654 rear wheel horsepower would convert to 815 stock horsepower at the crank. We know that the Hellcat Challenger is underrated at 707 horsepower, but 815hp seems like a real stretch.

In any case, Forza’s Hellcat Challenger upgrade packages with 807 wheel horsepower and a 20% drivetrain loss figure would be making around 1,000hp at the crankshaft. I dispute the choice to calculate crank horsepower by using the 20% factor and I imagine that many other people in the industry would agree, but that doesn’t take away from the fact that the folks at Forza have tuned up Hellcat Hemi to 807rwhp. Best of all, with fairly simple modifications that can be installed for $8,500 USD, the Forza Tuning Hellcat packages add big, safe power for a relatively low price out the door.


Rich Mark (not verified)    August 6, 2016 - 10:43PM

Interested in hellcat challenger stage 4 upgradeand how it differs from Hennessey twin turbo upgrade