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Discussion Starter #1 (Edited)
Head and Cam build results - less HP increase than expected

SO here are the results. I am disappointed.........

Now: 470 RWHP / 453 RWTq

Heads cleaned, port and polish
Custom Comp Cam (similar to 274; less aggressive)
Kooks LTH with Hi FLo Cats (not green cats)
Dyno tuned with Trinity
Dynomax Mini Race Bullet Resonators in place of factory resonators

Baseline: 435 / 435
Flowmaster Super 40 mid mufflers
Hellcat lower air box with inlet tube
 

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Discussion Starter #3
Petty’s Garage install and tune
 

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that's about right honestly.

I saw a 35 hp bump with a 392 cam swap in my little 5.7 with similar mods.
I'm not sure about scat pack heads, but stock eagles are good for up to 450 out of the box.
Did you upgrade the valve springs as well?

what does the curve look like? It may be making more power across the entire range just not that much more peak.
 

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was this cam supposed to make a lot more power, or were you thinking you would see improvements from the machine work on the heads?
For a cam swap and long tubes 35 is not unreasonable, but I would be interested in looking at your tune.
if you were using HP tuners I'd ask you to email it to me.
 

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Discussion Starter #8
Baseline was totally stock.....no tune

Picked it up today.
The shop did another run this morning after just warming up the car.

485 RWHP.

The run after the tune was completed heat soaked the engine causing a loss of some power.

485 RWHP is still not what I expected......but the car runs like a raped ape.
Feels like more that 50 RWHP increase. Definitiely feels like more than a 25 RWTq increase.

I guess the numbers are what they are.
 

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2015 RT 5.7 M6
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FYI

not exactly the same set-up but Arrington shows a 64hp increase at operating temp and 81hp increase best cold air run (scroll all the way to the bottom for the summary) on stock SRT exhaust.

Factory 392 6.4L HEMI Engine
Arrington Phase 6 Heads including CNC porting; Newen Epoc, Single Point, True Radius, CNC Valve Job; Hand Blended; PSI Springs; Viton Seals; hardened locators & retainers with stock SRT valves
Comp VVT 274 Cam: Intake Lift .619, Exhaust Lift .612, Intake Duration @ .050: 224. Exhaust Duration @ .050: 234
Comp Phase Limiter for VVT 6.4L HEMIs
API Chromoly push rods with .080 wall, and .210 radius tip
API Cold Air Intake
Stock exhaust from heads to tail-pipe

HEMI 6.4 and 5.7 Heads and Cam Package
 

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I agree that the numbers are what they are. That's a good way to look at it.

The way to see if it makes a certain number is to take it to the strip and see what it traps at. That's the best way to indicate that it's making power.

At least their tune is going the right way. How's the drivability with that cam?
 

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FYI

not exactly the same set-up but Arrington shows a 64hp increase at operating temp and 81hp increase best cold air run (scroll all the way to the bottom for the summary) on stock SRT exhaust.

Factory 392 6.4L HEMI Engine
Arrington Phase 6 Heads including CNC porting; Newen Epoc, Single Point, True Radius, CNC Valve Job; Hand Blended; PSI Springs; Viton Seals; hardened locators & retainers with stock SRT valves
Comp VVT 274 Cam: Intake Lift .619, Exhaust Lift .612, Intake Duration @ .050: 224. Exhaust Duration @ .050: 234
Comp Phase Limiter for VVT 6.4L HEMIs
API Chromoly push rods with .080 wall, and .210 radius tip
API Cold Air Intake
Stock exhaust from heads to tail-pipe

HEMI 6.4 and 5.7 Heads and Cam Package
Wonder why they didn’t raise the rev limiter and turn it a bit more?

Is there something in the 6.4 that comes apart above 6250 rpm?
 

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Discussion Starter #13
The rev limit is set at 6400 rpm now. The tuner told me that the dyno rpm and engine rpm don’t necessarily match up.

The cam is a 274 cam. It runs well. Idle at 800 rpm. Drive ability is great. Power comes on strong.

I will take pic of the new dyno later today.

The strange thing is that the new curve HP went up 15 and the Torque went down........that doesn’t seem right.
 

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The rev limit is set at 6400 rpm now. The tuner told me that the dyno rpm and engine rpm don’t necessarily match up.

The cam is a 274 cam. It runs well. Idle at 800 rpm. Drive ability is great. Power comes on strong.

I will take pic of the new dyno later today.

The strange thing is that the new curve HP went up 15 and the Torque went down........that doesn’t seem right.
it's the cam. Without VVT you get one or the other, but not both.
If you compare the curves on stock vs aftermarket cam, usually the curve shifts to the right unless you specify a low rpm high torque (towing) cam.
That's a really good idle speed for a fairly aggressive cam. I am wondering how mine will act in traffic with a similar cam setup, I doubt I'll be able to idle in first with the clutch out.

50 peak hp improvement for a cam swap and long tubes is average, the changes on the curve make more of a difference in driving experience/fun than the peak numbers.
 

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Discussion Starter #15
I get that the cam takes from one to give to the other.

But if I had 470/453 on Friday and the only difference is on Monday the car was run without heat soak then I got 485/430.......Why wold Hp go up in that case and Tq go down.....would both benefit from the engine being at a lower operating temp?
 

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I get that the cam takes from one to give to the other.

But if I had 470/453 on Friday and the only difference is on Monday the car was run without heat soak then I got 485/430.......Why wold Hp go up in that case and Tq go down.....would both benefit from the engine being at a lower operating temp?
in that case I'm not sure. unless the corrected value was skewed by and the atmospheric conditions (humidity, temp, etc).
Did he change anything in the tune between the runs?
I assume you are checking that there is zero KR during the pulls?
 

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Discussion Starter #17
No changes to the tune according to the tuner. Just hooked it up, let it warm up and run it.

No indications of KR.

I was told that this is a tune that does not pull out the most performance, but set for drivability and dependability.
 

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No changes to the tune according to the tuner. Just hooked it up, let it warm up and run it.

No indications of KR.

I was told that this is a tune that does not pull out the most performance, but set for drivability and dependability.
That's good. Unless it's a race car I sacrifice a few peak hp for a safety when tuning.
 

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The rev limit is set at 6400 rpm now. The tuner told me that the dyno rpm and engine rpm don’t necessarily match up.

The cam is a 274 cam. It runs well. Idle at 800 rpm. Drive ability is great. Power comes on strong.

I will take pic of the new dyno later today.

The strange thing is that the new curve HP went up 15 and the Torque went down........that doesn’t seem right.

They still have the rev limiter set to 6,400 rpms? I understand them wanting a safe tune, but any cam close to a 274 needs to spin. They are being to conservative.

The 6.4L is safe to 6,800 rpms, especially with upgraded springs.

If the limiter is set at 6,400, then they are only pulling it to 6,200 - 6,300. There is another 10-15 rwhp to be had at 6,500-6,600 rpms.

The idle can also be brought down a few rpms... maybe 725 or so. This is will enhance the lope for the cam.

At some point.... get someone else to tune it.
 

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Discussion Starter #20
I have gotten an email back from Brent. I would like to get him on the phone and pick his brain on what he thinks he can do for me.

He is tough to get a hold of.

Thanks for the input.

You get your car back yet? Or numbers?
 
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