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Hello I am new to these boards. I currently have a 2015 Jeep Grand Cherokee Hemi 5.7 and Durango R/T with 5.7 Hemi.

I was looking at getting the Charger Hellcat next summer, however with the durango SRT8 coming I may trade in for that. I am just curious as to what the 6.4 SRT8 engine produces on the dyno stock on average and what it would do with basic intake, tune and exhaust. For the tune I would think Hemifever or dyno tune.

Currently my 2015 Durango R/T has a 93 octane hemifever tune and AFE intake and its makes 325 AWP. So around 420 crank roughly.

I jumped to dodge from Land Rover & BMW this summer and love them. Amazing vehicles.
 

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no dyno runs by me so just posting until someone who has does...several dynos show bone stock 380hp ish at wheels, have seen 1 aFe dyno showing 18hp gain at wheels, cat-back exhaust is generally net zero and may rob from low-end and have very small gains mid+ but sure makes the beast sound more beastly :), 93 tune all the "butt" dynos seem to say "pulls harder", etc but haven't seen a discreet dyno run to show gains solely from a 93 tune....the SRT team really does put out a very tight, hard to improve total vehicle performance package....bolt-ons like these are for personal enjoyment and tinkering more than for true gains....the only mentionable gain package I have seen is a complete opening up of in (CAI, throttle body) and out (header back full system) and then a custom tune to get everything out of the new higher breathing/flowing setup...FWIW, the 5.7l is more "wakeable" than the 6.4l without the obvious force-fed real power-adders and you really should forge the motor if you go that route by all accounts....

don't forget to get yourself an oil catch-can not only on your SRT but your 5.7's as well...it's good for a much cleaner top-end (cup of oil every 3k ish doesn't get atomized in the top end) which most would say is good for 5hp ish but not sure anyone has ever isolated an oi-catch can's impact on the dyno...it's a nit that I happen to believe is kinda important on these motors...
 

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My 300SRT 2012 threw down a 410/412 in 80 degree temps. I'm assuming the Jeep is probably just under 400 at the wheels, which really means these cars are closer to 500hp.

Now that tuning is available, I believe people have got another 30-40hp max on good fuel out of them at best with stock intake and with zero increase from exhaust work. The motors generally don't have a problem getting air. They don't get much from intake exhaust bolt-ons, nor adding those with the tune. I've read about good results from a cam and tune with exhaust, but that's not a simply bolt on.
 

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My 300 did 390 at the wheels at two different dyno's, I apparently got a red headed stepchild 300. I am going to try and get the Jeep on a dyno next before any work gets done, planning on intake first, then full headers/exhaust.
 

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...I'm assuming the Jeep is probably just under 400 at the wheels, which really means these cars are closer to 500hp...
consistent reports of 380hp at the wheels bone stock...these drivetrains rob lots.
 

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Wow nice #s. Ive seen stock ones dyno under 350 to the wheels. 365/350 is normal

2014 wk2 srt cat-less headers cat back exhaust cai installed by true street performance tuned by a.j.

420 rwhp
Any sound clips without the cats?

So is that 420awhp? Or was this a rwd dyno?
 

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Geneva, way other side!

Sent from my SAMSUNG-SM-G930A using Tapatalk
duh! geneva-on-the-lake rocks....knew that from asking u in other thread :wink2:

as he said check out his threads for his build, it's a stoutly forged SC motor after he popped the non-forged first try....he is "Demon-ized"...
 
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I found out on a 6.1/6.4 a cai and good dyno tune or after JerseyBoy worked 1 of his tunes over real good is werth about 30 hp over stock. Now a good well worked over RACE tune using vp109 should get you another 10/15 hp to the wheels from what I have seen. Most dyno tuners will use a 1 to 1 ratio 4th on a 5 speed and 6th on a 8 speed.
 
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