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Does added boost change peak RPM on motor ??

944 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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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!
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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?
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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.
If you have or can get a good code reader with data logging you can see what the reported injector duty cycle is now without editing the tune or messing anything up. I use this one, and I've datalogged my HCWB with it before...

...and the included Android app and free Windows app both have data logging and fault code/check engine light code clearing capability. I don't remember what the PID is for injector duty cycle off the top of my head, but if there was ever a fault (even a "hidden" one that happened in the past but isn't active right now) this should display it for you.

Generally, a good OBD2 scanner is just a good tool to have in the tool box, and this one isn't a bazillion bucks.
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