6.4L Headers

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wrench04
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6.4L Headers

Post by wrench04 » Wed Aug 02, 2017 1:39 pm

Im looking into getting headers for my 6.4L
I think I'm set on the AFE long tube headers. They have 2 options, one with and one without high flow cats.
What is everyones thoughts on these? I will be getting tuning down the road but not sure if it is required to have the tuning on the race system without the cats.
Currently the only exhaust mod is a super 50 muffler.
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Re: 6.4L Headers

Post by Rodeoflyer » Wed Aug 02, 2017 3:02 pm

Have you looked into tuning options for the 2014+ 6.4l trucks? I did and eventually gave up knowing how expensive it would be with the tuning options (or OPTION being there is only one tuner I know of) and then needing to datalog to get everything right.

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Re: 6.4L Headers

Post by Colibri » Wed Aug 02, 2017 3:30 pm

Generally speaking, the type of high flow cats typically used are fairly likely to throw a check engine light periodically. Whether you go with or without you'll likely need to use post cat O2 sensor spacers to keep the readings in range and keep your CEL off.

Tuning will maximize your gains, but in the meantime perhaps do a hard reset and let the computer relearn fuel trim when you install the headers
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Re: 6.4L Headers

Post by Rodeoflyer » Wed Aug 02, 2017 3:40 pm

Spot on colibri. I used the spark plug/o2 spacers on my last set of longtubes with high-flow cats being in a smog county. I even had to double them up to clear the CEL. That took care of the CEL but I still think without tuning you'll be running rich. In a bang for buck sense you need tuning to maximize the gains of which there won't be much anyway with just slapping a set of headers on. Adding intake and cam/s with those headers it's another story. I just wanted to get the tuning figured out prior.

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Re: 6.4L Headers

Post by tds2957 » Wed Aug 02, 2017 8:15 pm

I'm running ARH long tube 1 3/4 high flo cat headers, with a magnaflo 19200 cat back exhaust on my 2015 PW. I went with the diablo I2 tuner and a new PCM, with a hemi fever tune. So far I'm loving this setup and haven't had any issues, except a bad case of hemi foot. I tow a toy hauler and was a little concerned about low end torq, but so far I'm very happy with towing performance. The truck definitely runs stronger mid range RPM's towing. Empty it's a beast. Even with traction control on, it will break the tires lose on anything slightly wet. Had a bit of a scare jumping on to the freeway got a bit sideways at 70 something, not a good feeling.
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Re: 6.4L Headers

Post by Rodeoflyer » Wed Aug 02, 2017 8:28 pm

I'm betting the tune had a lot to do with the outcome. How much was the diablosport handheld and new PCM?

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Re: 6.4L Headers

Post by wrench04 » Wed Aug 02, 2017 8:34 pm

So it'd may be wise to get a tuner first or save up and do it all at once.
Do we have any cam options for our trucks? Maybe I will save up and do everything at once.
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Re: 6.4L Headers

Post by tds2957 » Wed Aug 02, 2017 8:55 pm

Yes I'm sure the tuner had the most impact on the performance of my tuck. I think my new PCM and diablo cost me just under $1000. I'm sure anyone could argue how much or how little HP gain the headers would give you. I figure installing the headers before my factory header bolts snap preventive maintenance. The magnaflo cat back was my first mod, and well worth the money just to eliminate the stock resonator. Love the sound of the hemi with 4" pipe.
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Re: 6.4L Headers

Post by Rodeoflyer » Wed Aug 02, 2017 9:24 pm

Get the diablosport setup for $1000 first. That would be my recommendation if you plan to mod the engine. Any other engine mods will require it and diablosport assistance with datalogging for perfomrmance. We're probably less than 1% of diablosport business with the 'new' 6.4l truck hemi.

Its good they actually released something.

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Re: 6.4L Headers

Post by NickTF » Fri Aug 04, 2017 12:10 pm

Tunes are not witchcraft, these trucks would have to be awful rich with the oem programming or very short of optimal max power timing to notice big gains just from a tune. If these tunes are requiring 93 octane fuel I could see the tune providing lots of power through the use of increased timing and leaning things up. Don't underestimate the gains associated with long tube headers, especially on a large motor with the cylinder heads these 6.4s have flowing north of 320cfm and over 300cfm at moderate valve lift.

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Re: 6.4L Headers

Post by OffroadTreks » Fri Aug 04, 2017 1:49 pm

Dyno Tune it
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Re: 6.4L Headers

Post by Reloaderguy » Fri Aug 04, 2017 2:57 pm

NickTF wrote:Tunes are not witchcraft, these trucks would have to be awful rich with the oem programming or very short of optimal max power timing to notice big gains just from a tune. If these tunes are requiring 93 octane fuel I could see the tune providing lots of power through the use of increased timing and leaning things up. Don't underestimate the gains associated with long tube headers, especially on a large motor with the cylinder heads these 6.4s have flowing north of 320cfm and over 300cfm at moderate valve lift.
There is a guy on RF that dyno'd his truck with tune, long tubes, and full exhaust and reported +30hp. One of major benefits of the tune is the reduction torque management. The midrange should feel more stout because that is where TM is the most invasive.

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Re: 6.4L Headers

Post by NickTF » Fri Aug 04, 2017 3:09 pm

Sure, those gains are inline with ls1 stuff i've been involved with years ago, and those motors are smaller and don't have near the cylinder head these 6.4s do. Torque management is nothing more than throttle position and/or timing limitation so definitely power to be had by getting rid of it.

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Re: 6.4L Headers

Post by Rodeoflyer » Fri Aug 04, 2017 9:42 pm

30hp to the wheels I assume since it was dyno'd. That's probably 50 crank hp. Not bad actually...

I had murillo motorsports throw the Shelby on their mustang dyno and dyno tune it. A dyno tune is def the way to go but I kinda get a kick out of the whole high performance truck thing. I think of the wagon as a lumbering beast that crawls over things slowly. I may change my tune if those king shocks arrive :D .

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And yeah, tuning is in fact witchcraft.

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Re: 6.4L Headers

Post by wrench04 » Fri Jan 12, 2018 2:20 am

Pulled the trigger on a set of long tube AFE stainless headers with high flow cats.
Talked to Diablo today as well, they offer an exchange ECM program now on the hemis, unfortunatey all EXCEPT the 6.4L. Im going to go with a i3 Platnum tuner and send my PCM in to Diablo to get it unlocked for $200 then get custom tuning through hemi fever most likely.
Cant wait to get it all put together. I am currently running a flowmaster 50 series muffler. I purchased a Volant 3.5" resonator I am debating on throwing on when I redo the system. Im not sure if I should install the resonator and keep the muffler or have both. Im definitely cutting off the factory resonator. I tow a lot in the summer so don't want much drone. I wonder if the headers will eliminate some of the drone so I don't have to try and squeeze in the resonator into the system...
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Re: 6.4L Headers

Post by RustyPW » Fri Jan 12, 2018 4:17 am

In my experience. The headers will move the drone to a different rpm.
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