Hey guys I'm new to the forum and would like some info. This may be a dumb question and I believe its already been answered but I just want to make sure. I have a 2004 F150 with the 5.4L, as you all know these trucks have 4 cats and I recently received a code that said bank 2 catylist below threshold. I was told this means that one of my cats has crapped out on me so I decided to remove all the factory cats and replace them with two magnaflow cats. If I understand correctly from scanning threw this thread I need to get two 94106 magnaflows and I shouldn't get any CELs, am I right? I just want to make sure before I order them and get my local exhaust shop to install them. Any info and help would be greatly appreciated!

Also my future plans are to run pace setter long tubes, true duels (2.5"), crossover pipe, straight through magnaflows(not sure what length) and both tips exiting before the rear passenger wheel(probably 3.5"). Any thoughts on this setup? good idea, bad idea? should I go with the X or H? and what length mufflers do yall suggest?

I know this is a lot of questions, I just don't know much about exhaust systems and if I do anything I want to do it right and go all out!

 

^^^Adding to this^^^...

On the Magnaflow website, they don't list any newer mod-motor Ford trucks as a fit for the 94106. Just Windsor-based motors. Do they really fit or not? Any CEL problems or not?

 

I'll answer for your 02 model,- not the 04.

Yes they fit.

Nope, no cell problems what so ever. That's only if the if your system doesn't leak, = cat forward.

 

Is 3" the best size for a single exhaust on the 4.6 (1997)? I don't want to lose torque under 2k rpm. And what about the Aero Turbine muffler? I don't think I saw it anywhere in this thread. Just looking on Youtube I kinda like the Aero and the single chamber mufflers (cant be as bad as 2 and 3 chamber right?).

 

4.6? 2.5".

You should replace the VERY restrictive factory 'Y' with a Maggie Y-pipe in 2.5" in/out. Crossover from the left bank via a nice mandrel-bent section of pipe into the 'Y'.

Aeroturbine = gimmicky and unremarkable.

Go Maggie or Borla.

MGD

 

Thanks MGD. Is the theory that 3" exhaust would give me too much flow for the factory tuning? I see magnaflow sells a 3" mandrel bent tail pipe for my truck (no 2.5" for single exit), that would probably be cheaper than having a shop do it. What if I went 3" magnaflow with a little more restrictive muffler?

 

Hi.

Wellsir - the theory is the 3" will slightly reduce flow velocity and hence, scavenging. You want o maintain both to preserve low-end torque.

You can get a tailpipe bent at a good shop in 2.5". Yer not really talking about a full catback here right? Not piecemealing components here & there?

You do not want to insert a restrictive muffler as it will undo what you are trying to achieve.

I think most will agree that a shop will usually beat a catback kit on price. Choose yer muffler and have them fab the pipes. Although full mandrel SS is kinda costly. Kits are usually high quality, too. Need to do some comparative pricing.

If you go with a catback and can't find one in 2.5", going to 3" will be slightly noticeable - depending upon the sensitivity of yer butt-dyno, or not.

Regardless - that 'Y' pipe needs to go - it's a killer.

Where TF are the reg'lar Exhaust Guru's? I'm just the janitor!


MGD

 

^^^ Very helpful, MGDfan. ^^^ Thanks.

I plan to go full 2.5" mandrel-bent Y-pipe with Magnaflow cats and Flowmaster Y piece into 2.5" single to the back. I might go 3", since mine's a 5.4L. I just have to pick a muffler. This is for an Expedition, so I want it pretty quiet. I'll probably try the stock muffler with the new cats first, just to see how loud it is.

Honestly, I really like the sound of stock Yukon exhaust, with a nice throaty burble under throttle, and hope to approximate that. I know, it's probably sacrilege to emulate a GM. But that's what I want it to sound like.

Thanks, again.

 

Ok stupid question. I just bought a set of stainless steel shorty headers. Do I need to use the same length bolts as The stock exhaust manifold or do they need to be different?

I've been seeing 25mm and 30mm long 8 x 1.25 bolts.

Any idea which I should use?

 

I'd go same length as stock. The difference in flange width from stock to header shouldn't be as big as 5mm. Otherwise, you'll have header bolts that are too long or short. So better they be a touch short of touch long versus way too long or short.

 

Hello,

4.6 Punisher stated that the Left Bank works harder then the Right Bank because the tubing is longer, & has more bends in it.

This is VERY TRUE! But can be easily overcome, or at least minimized.
All you have to do is Borrow GM's Fix for the same problem, & Cross the pipes where they would have come together at the Y-pipe. Doing this will swap the exiting points for the exhaust, Making the Right Bank go to the Left side & there for helping to equalize the load by adding tubing length & a couple bends to it.

The Next tyme I do one of these, I will try to remember to take a Picture!
Just do not bash me for installing a FartMaster! I do this for a living, so I install what my customers want, & where I live & do business FartMaster rules!

For Chambered Mufflers: I personally Like MAC & SpinTech.

For My truck: I will be using a 2.5" MagnaFlow & 2.5" Stainless Pipe SI/SO, as she has a 4.2L.

 

O.k. i'm planning on installing a magnaflow sido, will my engine run lean or will the computer need to be reprogram? I also have the K&N 77 series cai which i plan to install after the Magnaflow. I have a 2013 3.7 f150

 

The Exhaust should not cause any issues, But the CAI & Exhaust together might?
You may want to ask this Question in the 2009 - 2014 Forum.

 

you need tuning software to support changes for the intake

 

Do you really think the magnaflow is alot better than the stock 3"inlet and 3"outlet stock muffler? On the stocker you can see staigth tru big bore. On the magnaflow sido , it has chambers and seems like the exhaust has to transfer from the center pipe to the two outlet pipes.What do you all think?