Well I spent a few hours yesterday getting the 392 manifold installed on my 14' rt six speed. Got it all wired up and set into place. I used the msd window switch method as I like the instant adjustability. I don't have any dyno results yet but I can def notice a lot better low end grunt and the Rpms climb a lot faster especially when the runners kick the intake to short runner mode at 4600 Rpms. I used a few different write ups form various other lx and charger forums. This mod was by far worth it, and not difficult at all. Feel free to ask questions on how to do this
The Part Numbers
Used 392 intake manifold- $150
Intake Pigtail connector 1-68064996AA- $29.00
MSD Box: P/N 8969 $129.00
Cirkit Boss: 70213 $70.00
Roll of electrical friction tape to give it the oem look. $2.33 from ace hardware
Below you can see I used a circuit boss to power the msd and the runner solenoid.
Here's the spot where I chose to hide the msd box.
It sits in the pocket behind the passenger side strut tower quite nicely!
Here you can see some of the wiring. The orange wires are going to the connector that plugs into the intake manifold solenoid. The white wire is what sends the rpm signal from the cylinder 8 injector to the msd box.
Thanks for the write up i was going to buy that intake and install it.I just put the 392 cam in and im not happy with it and i think this intake will help but i need to buy headers first.Can you change the rpms when the runners kick in??
Got my speedlogix 392 intake today and got it installed turned out nice. Keep in mind you will have to buy an extension for the intake temp sensor harness. Leg maker intakes sells a 9 and 18in extension. You will probably need the 18in
I never did get mine on the dyno, but with using the TTDyno program, I gained 20 lb/ft torque from starting point at 2,000 rpm up to 3,500. The torque equaled out just above 4,000 rpm.
Definately made for nicer street driving. I like your hiding spot. I mounted my cirkit boss in the same spot, and hid my MSD box up front by the wiper reservoir.
I have been curious about this install since someone mentioned that the intake would perform better on a cammed engine. I could maybe see that on the top end but I would expect the same 20+ on the low end from the long runners regardless.
Have you tried any other rpm's to have the short runners to activate?
I have the same set up as far as intake goes. I also have SRT8 shorties and a comp cam 270 with ported heads. I am thinking of trying 4800 rpms to have it activate and maybe 5000 rpms. My torque keeps building until 4600 and then starts dropping. I may change it, do some data logging and butt dyno. Then get some dyno time .
The 6.4 manifold definately makes a difference. Lots more low end(20-25 ft/lbs). I never did get a date worked out with the local dyno, but ttdyno showed 20+ torque from start (2000rpms) to 3500, then tapering down to 0 at 4200-4300. I have a dyno sheet from another member that did the same mod with the same other mods I have and it was identical to what TTDyno showed on mine.
I used plastic wire concealing tubing from AutoZone and then wrapped it in cloth friction tape. Ran my harness along another factory harness and tied them together ever foot or so. I put my msd switch on the fire wall. Hard to see so it all looks stock. Gained alot of bottom end.
I have completed this mod on my 15RT A8, but based on my dyno graph, I cannot verify if my short runners are engaging at my 4800RPM set point. I have 6.4 shorties/mids, flowmaster cat back, 6.4 intake, hellcat airbox. I havent done a tune yet, nor unlocked my PCM (will do that in winter)
Secondly, as of right now, my cirkit boss (pink wire) is drawing constant power from my fuse box. I have both mouser pins and the fuse tap here...but not sure where exactly its supposed to plug in? I have it tapped into my horn fuse right now (20A is installed in the lower fuse tap). I cannot connect to Ignition as its a relay box...What have other people done?? I have power to the unit, but its constant power image.jpeg Photo by Snowkan15 | Photobucket