I have a 2003 f150 with the 4.6 and a 5 speed manual transmission. The previous owner put on a K&N intake and a Duel exhaust system (not true dual, 1 in 2 out muffler) I want to upgrade the exhaust system with a true dual exhaust system with a x-pipe before the mufflers. I don't know what type of mufflers to run. I love hearing my exhaust nice and loud but don't want it to be obnoxious. Any suggestions?

 

Had to replace the muffler in my 87 150 5.0 used a Cherry Bomb. Once I get the body restored. Plan on headers, X pipe with a pair of them. Has a nice tone.

 

I had a 99 lariat 5.4 i went with a 3inch stanless from the Y back into a dynomax muffler it sounded awsome.

 

I assume you already upgraded the exhaust and muffler. What did you end up going with?

 

I have a heartthrob 4" cat back on my 5.0 with an aFe powerflow muffler. You might want to do a little research on flow characteristics of specific size pipe. Don't be foolish enough to think that two 2" pipes flow as well as a single 4". In fact, two 2" don't flow as well as a single 3", and you don't need to run an x pipe to equalize exhaust pulses. Not to mention the extra cost of pipe, and routing issues. Either way, Heartthrob makes a variety of quality systems, from 3", 4" to duals.

 

It's not like your motor will explode without an X, but why would you give up healthier engine operation if you're doing things anyways? A crossover for duals is always a good idea. A 4" single system, even on the new 5.0 that makes decent power, is going to move the powerband up slightly and doesn't provide for optimal scavenging.

 

The purpose of an X pipe or an H pipe is to balance the exhaust pulses. With a single pipe, both cylinder banks run through one pipe, therefore negating the balance issue. Think about it; the problem with a dual exhaust is that the cyclinder banks are seperate. With a single exhaust, the cylinder banks aren't seperate. Exhaust pulses scavenge in a single exhaust system. If you run a dual system, by all means run an X or H pipe. Both have been proven to add power. My point is that you don't need duals. If you like spending money needlessly, and making simple tasks complex; with no additional benefit, then run duals.

 

lol Somebody didn't read the link in my sig. Could have saved some typing if you read my exhaust write up. I'd agree in most cases duals aren't necessary (I'd argue in a 500hp supercharged 5.4L should have 3" duals but that's another topic), I guess I took it the wrong way about not having a cross.

 

Being an engineer and working in the Automotive Industry; I have performed and read many tests on various sizes of tubing. In theory, a 2 1/4" true dual exhaust system would only flow 69 more cfm than a single 3" system.
2 1/4" straight tube flows 408 cfm x 2 = 816cfm
3" straight tube flows 747 cfm x 1 = 747cfm

The Hennessy velocipraptor is 800 hp twin turbo and runs a true 2 1/2" dual system from Magnaflow. How much power does your 5.4 "with mods" make?

 

You're the only one talking flow here, I agreed with you that a single system is better overall for scavenging, so I'm a little lost on what your point is? I was talking about scavenging and the power band the entire time, I mistook you talking about singles or duals but that was it. Most any system will flow more than enough CFMs, it's more about optimizing scavenging at the best points in the power band.
FWIW I worked in an SAE testing facility for years.

As I said above, most any system will flow enough CFMs. Hennessy chose dual 2 1/2" because that's what Magnaflow makes and that's fine on all accounts. It's about how you want things to perform.

I don't see how my daily driver truck gets involved in this, but I'll give my reasoning. The truck dynos at about 330hp at the crank. In the 04-08 3V 5.4L, Ford uses a 2.5" single system. When the stock power increased for the 3V 5.4L in 2009-10 to 320 hp, Ford increased the size of the stock exhaust to 2.75" to better balance how the exhaust scavenges across the power band. I use a single 3" system, as it gives decent low end scavenging and doesn't stack exhaust pulses at higher rpms.