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Does added boost change peak RPM on motor ??

943 Views 19 Replies 6 Participants Last post by  Cosmic Blue
My Hellcat has a few mods done to it. It has a Liten Hellraiser 2.85 Supercharger pulley , AC Killer Chiller and has been dyno tuned. I didn't receive the dyno sheet. My question is does this added boost move the peak HP and Torque of the motor ?? I'm totally new to supercharged motors. Have only had this car since January. I don't want to damage my motor by over revs. Thanks for any input.
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Your pretend tuner wouldn’t answer that question?

[/QUOT Previous owner had everything done. He didn't keep any receipts or paperwork. Doc's Tuning and Performance in Nevada did all the work. Pulley , AC Killer Chiller and Dynatech headers and dyno tuned.
what do you want and what are you trying to pull ? Lol.
I was just wondering when going from a stock Hellcat pulley to a 2.85 Hellraiser if a person should still go off of the factory Hellcat redline ?? With added boost is it safe to spin it 6200 rpm's ??
I actually did talk to the tuner just a while ago. When they dyno cars they never go above 5200 rpms just for safety reasons. 725 WHP at 5200 rpm's. Said there really is no reason to rev it up over 6000 rpm because it makes so much power at lesser rpm's. He figures it would be about 770 WHP at 6200 rpm. He has done piles of Hellcats.
5200 RPMs is the redline for your tuner? That seems too low to say the least.

Ask your tuner what would it make at 6k RPMs. 750 ish. ?
Not the redline but that is all he takes them up to on the dyno. His tune makes great power every where so they don't press the limit on the dyno. Doc's Tuning and Performance in Nevada is the shop that did all the work to my car 3 years ago. I just bought this car in January so I'm trying to learn everything I can about it. He remembered working on my car and everything that was done to it. I had a very informative talk with them. He said it would be around 770 WHP at 6200 rpm.
Think what you want. Been wanting to find more out about my car. He did the same mods on my car that he has done to many other Hellcats. No need to piss pound each car on the dyno. This is their stage one install. Lots of power for the daily driver. Headers, unlocked ECU, AC Killer Chiller, and Litens Hellraiser 2.85 pulley. It has more power than I can completely handle at this moment. Call them on your own if you are doubtful.
So this is an interesting fast you CAN spin a HC is not the same as asking how fast you SHOULD spin a HC motor.

Strictly mechanically speaking, the valvetrain is not gonna like operation above 6750 or so. That's a LOT of RPM on a big 2-valve motor if you think about it.

On the other hand, without supporting mods and such there's not much to gain up higher either. So why go there?

Adding boost ONLY should move the HP curve straight up, not up or down the RPM range. However, it's virtually impossible to do that as you need more fuel with the boost unless you like running way lean and own stock in an aluminum piston foundry. :p

Not sure if that totally answers your question, but I hope it helps. Post back up as needed, and welcome to the forum!
The main reason I called them today was to question if I should put bigger injectors on my car. All the bigger injector and better fuel pump posts on here had me worrying. He told me there is nothing to worry about with starving for fuel with my car. Being there is 12,000 more miles on the car since all this work was done I really don't think there is anything I should be worrying about. I know the previous owner that had all this work done did not baby the car.
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It almost never hurts performance to upgrade the fuel system...but it does hurt the wallet! And you're right, it's not strictly necessary in all cases.

Do you know what your injector duty cycle is maxing out at right now?
I'm sorry but all the work on my car was done 3 years ago. And by the previous owner. There are no records of anything. Previous owner didn't save anything. But he told me where all the work was done so I tracked them down. Wish I had more answers for you and myself.
It’s super simple

You bought a car

Drive it like it is or take it apart, see whatcha got, and go from there with a build
Yep !! I'm not touching a thing on it. I'm still getting used to the power. I evidently don't drive it often enough lol !! Car is a handful for me even with the Mickey Thompson Drag Radials. And I'm being a little careful with it as it is my newest car. Replaced my 2010 SRT8 with 10,000 miles with this Hellcat. There is absolutely no comparison. I'm learning some things or two about the parts added to this car and just find it interesting what they do. I've never owned a supercharged car before. I had no idea what an AC Killer Chiller was and had no idea what a smaller pulley did until I started reading on here. Rookie here !!
Oh, you are wondering if you will overspeed your supercharger, yes?
Yes I don't want to damage my engine.
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