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What performance mods are needed for a stock regular Hellcat to be as fast as the Demon and C7 ZR1 Corvette?

1769 Views 10 Replies 4 Participants Last post by  Bhdau1
Curious to know what performance mods a stock regular Hellcat needs to be as fast as those two cars?

Is a tune, 2.85 pulley, and injectors sufficient or is there a little more performance modifications needed to get to that fast level that those two cars are at?
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C7ZR1 is faster from a Roll than a Demon. So the answer is different for each car .

To beat a ZR1 from a roll- you’ll likely need upper, lower and E85. Cat deletes for sure , but maybe some headers for good measure .

To best a Demon in the 1/4mile you’ll need , gears, radials, some traction work (control arms, bushings, trailing arms) driveshaft,upper/lower and corn.

maybe it can be done with less - but that should do it

Very good thank you. So it seems like the power mods I'd need would be both an upper/lower plus e-85.

What upper /lower combo would you recommend? 2.85 upper and 10% ATI OD lower?

Let's just say I started with the mods I mentioned which is the 2.85 upper, upgraded injectors, and tune but don't want to run with e-85 or any other race fuels.

What additional mod would I need to compete? Maybe just a 10% lower?

Would just a 10% lower pulley combined with a 2.85 pulley, 1050X injectors, PCM/TCM tune be good enough?
I’m actually not the guy to answer that one man. I know there’s a limit to what you can do with upper and lower pulley on pump .

Gearhead Fabrications did an upper/lower Hellcat with big HX and intake and did 10.00 in Florida heat with it @ 137mph ….it made 820whp that was on 93- but if you’re running against a ZR1 on the street you’d better hook up and even still you’ll be fighting for an edge .

maybe you could do upper and lower on pump in a regular Hellcat and still run on 93 ….but some cooling mods would be in order and maybe some headers to help with the breathing - but I’m no expert in that .
I doubt you’d have full timing and I’d bet you’d be running on the rich side to keep it safe . C7ZR1s trap high 13X- on pump you’ll be hard pressed against one with a full weight charger - they have a major weight advantage and aero to boot.

Good points you brought up, appreciate it. I think that ZR1 is gunna be some good hefty mods to compete with… probably like an upper/lower e-85 type of deal like you mentioned. Like a dog chasing a rabbit lol.

The minor mods I mentioned like the tune, upper pulley, and injectors will probably be faster than a Redeye and C7 Z06 but for the other two cars I might need a little more sauce for probably.

I heard good things about Gear Heads as well as American Muscle Performance in Pompano beach. Have you heard of AMP? If so, which of the two shops would you choose to get your car worked on?
I would suggest you contact High Horse Performance in Delaware. Not sure where you are located but I was able to ship my car to them from Lexington Ky. which is more than 10 hours away for $2000 bucks round trip on a single car trailer. The car never gets touched except to take it on and off the trailer at the shop and my house. It could have been shipped for a lot less if I wanted it on a multi car trailer. I told them about all the modifications I had already done myself, my horsepower goals, and what budget I would like to stick with and they did a phenomenal job. After they got the car I even added some AAD suspension parts to the list of things I wanted and told them that they could add anything they needed to essentially and they did not up-sell me on a single solitary thing. Most places would have pushed me to add parts I didn't really need to make more money. I even suggested a few things that I had read about to add to the build and they talked me out of them, explaining why they would not help performance or how they would hurt the daily drivability of the car. The long and short of it is I spent about $25k with them and I have a bulletproof Redeye with two tunes and 2 different upper pulleys that are easy to switch out. One is for "high" boost on E85 making 945 wheel horsepower and one is "low" boost (slightly more than stock) for 93 octane that makes 830 wheel horsepower. They dyno tested it and give you the results and video of your car on the dyno to boot. I have been under the car and all through it and all of their work appears to be top-notch, no loose bolts or shortcuts. I would contact them and tell them your budget and ask them to come up with a build plan that will maximize power for your money yet stay as reliable as possible. I should mention I also contacted Forza Performance Tuning in Florida (Brenton Brown) and National Speed in Wilmington, NC and got quotes from both of them. While all three places used some of the same parts, there were differences between them all. I felt HHP's build sheet was the best and their reputation as THE BEST Hemi guys in the U.S. made me choose them. It wasn't exactly super easy letting go of the factory warranty only 13k miles into it on a car that stickered $92K, so I wanted the guys that would do things the best way using the best parts so the car would still be a reliable daily driver if I wanted to.

Thank you for sharing. I live in South Florida so HHP is pretty far from me. I've spoke with shops down here and like Gear Heads Fabrications the best and there pretty good. You did bring up a good point about HHP and I've heard a lot of good things about them as well.

I'll give them a ring and see what they have to say. Sometimes you may want your car in the best hands possible even if it costs the inconvenience of having to get way out of your way.
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