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392 manifold and mids on 5.7

11K views 23 replies 9 participants last post by  BigDaddyWiz 
#1 ·
I have the opportunity to buy the stock shorties and mid pipes off of a 2014 super bee. I have a 2015 challenger R/T 5.7 6 speed. I was wanting to know if I'd be running into any obvious obstacles while trying to install such as ; CELS, O2 SENSORS wire lengths, etc. Looking for some help, thanks!
 
#4 · (Edited)
You'll need the mid-pipes (these have the cats) - the flange position is different from the 5.7 version.

Also, the O2 sensors require longer leads, since the position is different on the SRT shortys vs. the 5.7 CI manifolds.

The 392 intake manifold is active (runner flaps that moves from short-runner to long runner for better low-mid range torque) the 5.7s don't have that provision, nor is the PCM set up for it.
(the manifold would probably be in long-runner mode w/o powering the motor that operates the flaps).
 
#6 ·
Ive had no engine lights with my 14 model after 2 or 3k miles. Also, no O2 sensor extensions were needed on mine. The passenger side was just a little snug on slack but not bad.
 
#10 · (Edited)
I did this a few months ago. SRT8 short headers and catted mids onto my 5.7. There was nothing movable on my headers so I am unclear of the above comment about adjustable flap. They went on with the normal PITA that in car header swaps have but they fit into the car. The catted mids are also required as noted above, the flanges are different. The wires fit on my car though some say that you need to peal back the wire harness a little to get slack. My battery was disconnected for the work to be done so the computer resets to square one and learns the car all over again from scratch. In addition to the headers/mids, I have a 3 inch pipe and low restriction mufflers and no resonators. The stock computer settings handled it all with ease and there have been no codes or issues since the install about 3 to 4 months and at least 4K miles ago.
The oil dipstick tube will need to be altered to fit but it is possible to use the stock one, there is even a thread someplace that says that you can use a long stud and a nut to stand off the oil tube the correct amount without bending the tube.
I am sure that you might pick up a little better performance on a Dyno but I have doubts about a canned tune. I will be adding a blower very soon so it would have been foolish to spend $500 on a Dyno tune just to do it again less than 6 months later.

I only have a butt Dyno to go by but I am GUESSING at about 14 HP and Torque pickups for the swap. I did it in prep for adding the blower. I am not sure about the cost effectiveness of doing it without other mods due to the high cost and modest gains. On a second note, I have NO faith in CAI. I added one to the car and I also configured gauges to read inlet air temp and room temp. I found that at highway speed, both kept air temp to about plus 3 deg F to room temp air. At a stop on a 80f day, the "CAI" climbed to 160F (yes the "walls" were properly in place) while the factory box only hit about 130 F under the same conditions. The factory box also slowed the rise in temp swing so that there was cooler air available at nearly all times with the factory box. The factory box flows about 770 CFM while the CAI was rated to over 1K CFM but at the stock engine does not use everything that the stock box can provide, the CAI abilities to flow more air was a paper number only, not one that means anything in real life.
I will be using a in the fender CAI with the blower, much the same as the stock box does as the stock box has a foam gasket to seal the inlet to the fender well and it does not use any air from the engine compartment. YMMV!
 
#11 ·
I ran them for about a year and although I did not dyno to see the gains, it seemed to be about 15-20hp.
 
#12 ·
So it somewhat of a noticeable improvement on sound and performance? Btw, I did the CAI, with the headlight mod for more air along with a resonator delete. The mufflers are pretty straight through being that they're the bottle mufflers.
 
#13 ·
Sound wise yeah it changes a little bit. You will notice a slightly different tone or sound from the exhaust. Performance wise, no it's not very noticeable. You will be a lot quicker learning exactly how your car likes to launch vs doing this mod and having mediocre launches. If you are already good at launching your car from a stop, then yes there is a slight improvement. If you have the cash I recommend getting long tube headers from the get go. These gave me 20 horsepower over the SRT8 manifolds I had on, but the motor was not stock.
 
#14 · (Edited)
i did this this past May and the only problems was wrestling with the headers themselves....its a super tight fit but luckily, i had the help of my friend who is a tech and we had it on his lift with all the swivel tools in the world (those will be your best friend during the install). i also ended up using the SRT mids and bought the MBRP cat back (SRT sized) to mate up with the mids no problem. you may also want to get some extended o2 sensors just in case. i bought a few off rockauto. i'm sure if you search you can find the part number. i dont have it handy unfortunately.

also, as mentioned above you can either modify the stock tube or buy an SRT tube (which is what i did). the only thing i had to do was notch the stick once i had it in because the SRT dipstick is longer than the stock R/T one.

i had zero issues with codes. in fact when i took it to get dyno tuned it was still safe enough that it wasnt too lean. this may be due to the fact that i was running a custom email tune from OST, but after i had him do his thing, he said i was making about 50 less peak HP than the average stock 392 that he sees on his dyno and said it was the strongest mildly modded 5.7 he's done (and he does a lot). i also gained across the entire RPM range compared to the email tune. butt dyno agrees. it feels really good and the SRT headers are good up to 800hp from what i read. no wonder they are the same ones used on the hellcat :)

the key is getting the car tuned for the headers after the install. if you just slap them on and expect a major power boost you will be sorry. honestly, with my mild mods, longtubes wouldnt have been worth the extra money and pain the ass.
 
#15 ·
FYI I was surprised but the long tubes I put on we're actually easier than the SRT8 manifolds.
 
#17 ·
Ive done 1 set of Borla headers, and 2 sets of BFE long headers and they are a lot easier than jacking with the SRT manifolds. The claim shell really takes away from extra room for your hands.
 
#18 ·
I'm having a Chrysler technician do it so I'm not too worried about the tools or lift. I was just really interested in what kind of gains and extra parts I'd need when I took it to the shop. Y'all have been extremely helpful. I was just looking to get a little more out of this car. This car has no trouble chirping 4th so I figured I'd get more air in and out then leave it stock till warranty goes completely out.
 
#23 ·
My mods are in my sig. I will PM later though.
 
#24 ·
ok, i see them now. thanks buddy.
 
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