Hi, First off, I have a 2001 F250 with the 5.4L. What is the stock exhaust size inlet to the catylatic converter? It looks like 3" but Im not sure.

I want to go with a Magnaflow cat, Magnaflow muffler, and a tip to exit out right in front of the rear tire on the passenger side. So, Im basically gonna cut off the stock system right in front of the cat, and get some clamp on tubing and run the cat, then the muffler, then get some of that flexible tubing or a piece thats already bent to the right angle that I need and turn it to the side and hang a tip there. I was thinking since its only one pipe to go 3" all the way (except for the 4" tip). Is that the right size? And do any of you see a problem with the setup that I may encounter? From looking at it and thinking about it, it sounds good to me. But Im not an expert.

 

There is 4 cats on your truck.
Are you planing on adding another one? Or are you cutting 4 of and adding 2 Magnaflow high flow cats?
I think the stock size pipe is 2 and 1/4,,,might just be 2 and 1/2

If you going to run just 1 pipe then 3" would be good.
True duals,,your better with 2&1/2

 

my truck only has one huge cat and one huge muffler. its the gas 5.4L. im gonna put 1 universal cat on and 1 universal muffler and run basically how it is now with one pipe cause the muffler shop said that they cant do it out the sides behind the rear tires like i want it cause of the gas tank on one side. and i cant have it out the back strait cause i have to back into a ditch to get to my back yard and they would drag. broke em off my tundra that way.

 

Well since you have the same motor set up as I do(5.4) I just figured you would have the same exhaust set up too.
Never heard of a 5.4 having just one cat.
Looks like you'll save some money on a cat and muffler...lol Good for you.
Let me know how it turns out.

 

No, some of the 5.4L Super Duties had just one cat. No way will a Magnaflow weld in universal work for you, they can't handle the load of a 5.4 by themselves, regardless of what the manufacturer says. Their direct fit part for that application is no winner either, it is identical in performance and size and has the same tendency to fail as the OEM part. You may figure I'm just ripping on Magnaflow, but I just don't trust them. I see more Magnaflows bite the dust in my market than all other brands combined. You need a cat that is somewhat more substantial.

To answer some more of your questions, the stock size is 3", Flexible tubing is not meant to make bends, clamps leak, can trap corrosive materials, and weaken the system. Welding is much better. If you do clamp it, there are clamps out there that are designed to seal all the way around, I know Ford uses them for some of their OEM stuff.

 

All 99'-04' 5.4l and 6.8l SDs have one cat. 05' up SD 5.4l and 6.8l have 2 cats.

The entire exhaust is 3" from the Y-pipe back. Running 3" will be ok. I wouldn't use any flexible tubing. Use a 90deg mandrel bend or have an exhaust shop make a bend for you. Weld at much of the exhaust as you can, however my local exhaust shop clamps the muffler and the pipe behind behind the cat for easy removal later. Use good quality clamps and make shure they seal. I have a Dynatech cat on my truck and so far its working well. I have pics in my gallery of my SD.

 

who makes a good cat then?

 

I am proably gonna get flak for saying this, but we over at Bear River have cats that are ideal for your application. They are better that whatever else anyone else is selling. In anticipation on their objections I will prepare the advantages that no other brands offer.

1: completely stainless steel design, everyone else uses at least some aluminized or galvanized materials.

2: Heavy guage malleable materials. Other companies use brittle light guage metals that crack, split, are difficult to expand, and are easily burned through with an ordinary mig welder.

3: Advanced substrate that is free flowing and more efficient than other products, and lasts longer, which is why our product has twice the warranty of other brands.

I don't care what brand you are reffering to, all of them fall shy on all three of these points. And this is with price out of the equation, our prices are extremely competitive.

Again, I repeat I know am am gonna get flak from someone about making these statements, but if someone can disprove me, please come forward. As a sponsor I do have a right to make such statements, and I do have a right to promote my product and have a fair chance. It is the support of sponsors that makes this site possible.