Wow, you guys have me totally confused. When I first started at what mods to do I kept reading about 3" pipe and flowmaster mufflers. Once I get ready to install one, I read how it cuts low-end torque, no noticable difference in performance or MPG, etc.. Was thinking of going 3" in, 50 series muffler, single 3" out. Can someone shed some light on (1) What's the advantage of getting an aftermarket exhaulst (2) what size pipe and type of muffler to go with.

I have a 2002 Screw 4.6L, K&N drop-in.

Thanks for any and all help.

 

1 I can not answer.
2. Take the muffler of put a 2,5" pipe instaid save your self a lot of money and be happy with your truck.,,,

 

Get a SI/SO Flowmaster 40 or 50 series muffler. If you want to keep your backpressure, dont go with a straight pipe, get a muffler. And limit your pipe size to 2-1/4" going out of the muffler. The stock 2-1/2" pipe going in the muffler should be fine. Get 2-1/2" inlet, and a 2-1/4" outlet size on your muffler. I don't know if it should be off-set or centered on the inlet/outlet, so just ask a muffler shop or call Flomaster. Oh, you won't be disappointed.

 

Thanks for the help guys. Curiosity, So what's the hype with the 3" stuff all about? Trying to learn here! Thanks again.

 

Basically, 3" pipe gives your exhaust a deeper tone that's all. And it will free up some HP depending on engine size. Usually you will see 3" pipe on race cars with large high horsepower engines. It free's up alot of horsepower on these engines, but not on the factory engines Ford makes. But on smaller engines, with 3" pipe, you will lose backpressure. (lowend power) You might see 3" exhaust on a Lightning, but it's not really needed on the smaller engines like the 4.2 and the 4.6. Just my 2 cents.

 

Well today I finally did it. I was driving by the local muffler shop and they were not busy, and one bay was available. I wheeled in and had a 40 series, delta flow flowmaster muffler installed on my 2002 Lariat 5.4 litre. I kept all the stock stuff and ONLY replaced the muffler. I have to say that I am real pleased with the sound and I am not sure if it is my imagination, but the truck seems to have more power.

Can anyone comment as to whether I can expect better fuel economy and HP by just replacing the muffler and not messing with the stock pipe?