I am looking for an inexpensive exhaust solution for my 2005 STX with the 4.6L. Probably just looking for a better performing muffler then stock and will probably use the stock pipes if possible. Anything out there that will help will gas mileage and sound? Anyone help is appreciated.

 

i added a flowmaster 40 series to my stock pipes and love the sound and performance. has a nice rumble to it and good sound inside the cab. muffler ran 60 bucks and another 45 to have it installed. a shop cut off the factory muffler added the new one and needed a 9 or 10 inch piece to add to the tailpipe. i also added a k&n air filter which i think helped the whole system.

 

What are the sizes of the muffler inlet and outlet for my STX 4.6???

 

2.25" = 2&1/4" I used a 2.5" on mine and it sounds much better. I also used the stock exhaust pipe on mine.

 

So if I want to use my stock pipes I need to find a muffler with 2.25 in and 2.25 out, or am I confused?

 

I have an 04 STX and was thinking of getting dual exhausts, I read somewhere that a series 40 from Flowmaster was loud. I was thinking of going with a 50 series Delta muffler. Did you think that the 40 series was too loud inside the cab? That is my only concern with that particular muffler.

 

Yeah, my brother just ook off his 2 month old 50 series delta and replaced it with the flowmaster 40 series on his Tahoe. Im thinkink the 50 series will be a perfect fit for me.

 

I used a 2.5" one that I had lying around from a mustang project. 2 small pieces of tubing were used and the original pipe/tubes was inserted into the new pipes/tubes. Then welded together. I reallly don't think the 40 series is that loud in the cab either.

I enjoy being able to hear the truck for once.

 

What ill affects, if any, will welding 2.25 pipes to a 2.5 muffler cause. Just doesnt sound right to me to have different size pipes than the outlet.

 

I am having my local Muffler Shop do up a custom True Dual Exhaust on my 04 F-150 STX SCAB 4.6L for $250. He suggested using 2.25" pipes because you "loose a lot of your low end torque by going up to the 2.5 and 3" pipes". That is with 2 Magnaflow mufflers and Chrome Tips. I am having them exit out, in front of the passenger side rear tire.

I thought that was a pretty good price considering the CAT Back systems cost around $400, and then you have to install it, or have it done, which cost even more money.

 

Why run true duals ?

 

Equalization, more flow, more horsepower. If I could, I would cut those converters off too! I suspect that is the reason Ford went with 2 Cat. Converters in 04, so we could run True Duals, or they feel that they were able to provide more exhaust flow using two instead of one. I'm not sure about that. Just a guess.

We would have to ask an expert this same question to make it all more clear. But, everything I have ever heard has led me to believe that, it is better to keep your exhaust sides seperated, and equal in length.

I will ask when I pick up my truck Tues. or maybe somebody else can chime in on this one in the mean time.

Think of it like this. On my truck, I have a 2.25" pipe from each ex. manifold, going to its on collector, then they merge into one with a "Y", then into the stock muffler. So right now your max air flow is restricted to what a single 2.25" pipe can provide. Even if you run dual outlets on your muffler you still have that 2.25" bottle kneck.

If you cut off the "Y" and take each pipe into it's own muffler then you have the ability to provide more air flow because you have twice the capacity.

It all makes perfect sense in my clowded understanding!!!

 

I think unless you running over 360 hp to rear wheels si/so would give you the most gains unless runing headers
then true duals just my 2cents

 

I respectfully disagree. IMO, there is no way a SI/SO, or even SI/DO can be better than running duals all the way back. Unless, you increase the diameter of the pipe from the "Y" on back, to say 3" or better, and I don't think that would even be as good.

It doesn't matter if you are running 360hp or 160 hp, twice the airflow will make any power plant run and breathe better.

In Pylda's situation he is looking for an "inexpensive exhaust solution" so...you would be correct, cutting off the stock muffler and replacing with a high flow muffler of his choice would be the ticket. It's cheap and you will reap some benefits in HP!

--
KBL

 

Ok...so that said, which muffler would you guys reccomend? Once again Im looking for performance over sound. Dont want anything that will wake up the neighbors, but something that will aid in mileage as well as horsepower, maybe.