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Discussion Starter #1
So, i've been interested in knowing how much HP is truly lost at the wheels with these cars. I've read anywhere between 15 - 20%. Since these cars have the BHP and torque gauge readings as part of the SRT computer module, i figured i could strap it to a dyno, while sitting in the car and reading the HP gauge to get an accurate comparison.

This is what i got:
RWHP 439.2
BHP 545

That is roughly 19.4% HP lost at the wheels!!

This was done on a '14 300 SRT, Hennessey CAI/Corsa Extreme exhaust/custom Tune.

I'll post a screen shot of the 545 gauge reading, and the dyno sheet here shortly for you all to see.

Honestly, i did not expect these high readings with just the bolt-on mods, but i read somewhere that the quoted stock 470BHP is really understated due to the extreme conditions these motors are tested in.
 

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Wow, 19.4% is like AWD percentages of loss. And your 545 BHP is pretty incredible for those very basic mods. Either the tuner is a WIZARD like I have never seen or it's a bit fudged somewhere....
 

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Discussion Starter #3
wouldn't doubt there is some glitch somewhere that gives off these readings...i did do two separate dynos with similar readings. the second read 435rwhp / 537bhp.

Still trying to figure out how to upload these pics... :aargh4:
 

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The dash gauge is not measuring crank HP, it is just estimating it, and it can be off considerably. Once you start doing mods/tuning to the car, it is going to be off even more.

Many of the 6.4's are putting down 420-430 RWHP stock, which means that the 470 published number is probably low (as you stated). Once broken in, these cars are probably closer to 490-500 crank HP in normal conditions. The 470 rating is in the absolute worst conditions. I would go with about 15% loss for the 5 speed auto trans.

With your additional mods/tuning, it's possible you could be in the 505-510 range in ideal conditions.
 
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That's a big loss, but don't sweat it. It's pretty much useless to even compare dyno numbers as all dynos are different, not to mention the operators. Dynos are nothing more than a tuning tool. Put it on the dyno before and after mods and make comparisons, get the tuning parameters dialed in, etc. The comparisons "My car made this much power" and "his car made that much power" are not useful, unless they were on the same dyno with the same operator on the same day. I've got a buddy who spent a bunch of money on an old Mustang, and the shop that did all the work has a dyno. He got the "feel good about what you spent here" numbers from some dyno runs. It "supposedly" made 480 hp to the wheels, but it never felt that strong and the best he could do at the strip was a high 13 at 105 mph. Hardly what would be expected from a car that really had 480 hp. I trust your numbers are more accurate than what he was given, but this kind of thing is just something to keep in mind when comparing numbers.
 
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Diablosport intune is highly recommended by me, got it last week. Huge difference in mid to high range rpm power. Shifts are quicker and more solid and a lot more response in the gas petal. It even sounds different all for the better.
 

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Diablosport intune is highly recommended by me, got it last week. Huge difference in mid to high range rpm power. Shifts are quicker and more solid and a lot more response in the gas petal. It even sounds different all for the better.
what tune did you use? what settings? my gas mileage went up around 2 mpg with the 91 tune
 

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Going back to the op... 18% is about average on a 5spd auto for loss... 20% for an awd... so I have been told by some pretty reputable fellas!
 

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My story is the same as WalterWhites, I dyno'd 460rwhp with only diablo91 tune, muffler delete-welded active vales open, and cold air. This blew away everybody at the shop (was a dyno night with 30+guys)
And I recalled reading from here a year ago one member posted a bone stock dyno of 410rwhp and everybody bashed him. It makes sense that the actual crank output is 490-520hp.

I did not play with any custom settings on the tune, and I strictly use Shell91 Vpower. I get 400kms per tank avg.
 
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