Hey guys i just need to know what size my stock exhaust tubing is in my 1997 expedition with a 5.4. Im planning on gutting my pre-cats and replacing my cats with hi flow ones. Then im goin to put on a magnaflow cat back. How do you guys think that would sound?

 

stock size should be 2.5 inch.

 

ok thanks
how do u think that would soumd?

 

high flow cats and a magnaflow setup should sound nice. she will be breathing alot better.

 

instead of just gutting the precats, pull them out & replace them with regular 2.5" piping and them put in the high flow cats, will be mean, loud & more powerful.

 

I gutted my precats, and had a noticable sound increase. I personally dont like magna or flowmaster, just b.c they are so dang expensive, but i think it will sound good

 

Ok well if i go with replacing my precats with normal pipe what angle do you guys think that would be like a 45 degree? So i can just go to napa or someplace and buy a 45 degree piece of pipe and cut it to whatever length i need. That way i dont have to bend anything myself.

 

its probably closer to 40* but i cant say that for sure, just what i remember from a couple months ago when i did mine

 

ok thanks guys for all the help

 

shop by me tells customer to take a coat hanger and runalong side the cats -on ctr and include any bends and how long they want pipes made- he then bends a pipe -females the ends -this resembles the bend of the coat hanger the customer shows him- the customer then cuts the cat out- then loosens the y-pipe at the joint of the manifolds ,installs the fabbed pipes then all is good-phil

 

Ok guys i think i decided im just going to bend all the pipes myself. Ill be replacing all the stock piping from the headers back. What do you guys think about going to 3 inch piping. The stock is 2.5. Will i notice a difference? Are there any performance gains or does it make it any louder?

 

well wait are you not going to be running cats? or run the stock cats without pre-cats? If your keeping the stock main cats then from headers to cats the piping should be 2.5" for max torque, though it will be louder, you may lose power, & if your going to run true dual pipes 2.5" is most prefered for the most available power but 3" pipes just may sound a little louder

 

No im going to get rid of my precats and put normal pipe in place of them. Then im going to replace my normal cats with hi-flow cats. I was just thinking about replacing all the stock pipe and a new y connector into a magnaflow cat back. Whether it would be worth going to a 3 inch pipe or staying with the stock 2.5. Also if i end up replacing the stock pipe how could i thread in the 02 sensors?

 

oh ok, well the y pipe that connects the pipes to the mid way pipe should remain 2.5", the midway pipe you can keep 2.5" too or 3", theres not really a sound or power difference I have been told, but with high flow cats i'm unsure, a 3" pipe just might help it sound louder. I believe my F250s si/do kit is 3" in & 2.5" out so that might be the muffler inlet sizes you would want to look out for too.

 

ok thanks