5.4 Dual in/ Dual out muffler

[IRONMAN]

You running the tuner still?

I was then took it off, same thing.
Put it back on and still same.
Now I just took it off again and am running full E85 with a bottle of injector cleaner to see if I can clean some shit out if it's in there.
As soon as this tank is empty I will go back to the 93 octane and see what I get again.
Mind you I've been doing all this in the past 3 to 4 months to test.

---------- Post added at 05:09 PM ---------- Previous post was at 05:08 PM ----------

Thing is AS SOON AS I got the exhaust installed MPG dropped 2-3 MPG.
Was not hammering it.
Talked to Mike a 5star and he said nothing on the tuner should have to be changed.

 

[pirate air]

Not uncommon to lose torque with less back pressure. The intake manifold and camshafts profile are most efficient around x amount of back pressure. The three (exhaust, intake manifold, camshafts) are designed to work together. Mess with the back pressure too much and you have cylinder scavenging problems. Its more prevalent in your case with the headers.

 

[Ruger]

Ironman, I had a similar problem years ago with a Nissan 2400cc 4x4 D21 truck. Installed a header and Flowmaster, and it sounded like the Space Shuttle launching. It was illegally loud. I called Flowmaster and described the problem, and they recommended the installation of a resonator upstream from the muffler. I said, "Wait a minute. You mean I have to buy a resonator from you just to make your muffler muffle?" The guy said, "No sir! I'm going to send you a resonator free of charge." And he did, too. It solved the problem and I had a rich, deep exhaust note from that little 4-banger that didn't drone.

 

[IRONMAN]

Not uncommon to lose torque with less back pressure. The intake manifold and camshafts profile are most efficient around x amount of back pressure. The three (exhaust, intake manifold, camshafts) are designed to work together. Mess with the back pressure too much and you have cylinder scavenging problems. Its more prevalent in your case with the headers.

Ironman, I had a similar problem years ago with a Nissan 2400cc 4x4 D21 truck. Installed a header and Flowmaster, and it sounded like the Space Shuttle launching. It was illegally loud. I called Flowmaster and described the problem, and they recommended the installation of a resonator upstream from the muffler. I said, "Wait a minute. You mean I have to buy a resonator from you just to make your muffler muffle?" The guy said, "No sir! I'm going to send you a resonator free of charge." And he did, too. It solved the problem and I had a rich, deep exhaust note from that little 4-banger that didn't drone.

I have 2 X pipes in-line now which I think made it worse. Muffler has internal X and then an X before it.
So what should I do? I just bought 2 magnaflow universal mufflers #11259 18x4x9 3"OD. The exhaust in now is 2.5".
Am I going the wrong way?
I was going to get a 3" X pipe to place before them.
Should I do the resonators?
I was trying to mimic SW set up with the 2 mufflers cause I figured the Magnaflows would be a bit quiter.

 

[Captain Awesome]

you will want the x pipe in place of you'r y ( right where the 2 pipes from you'r headers/manifolds meet. then mount your muffler as far back as possable. 2.5" is good for everything as you'll have dual pipes and is good enough for a na engine. no need for resonator as the mufflers you picked should be quit enough and if there not then you can always and some between the mufflers and x pipe later to tone it down.