I have never seen this setup mentioned here. I've found a Flowmaster SUV 50 series muffler with double 2.25" inlets and single 3" outlet. I plan to give this a try as the double inlet pipes will eliminate the restrictive factory Y-pipe and the need for X or H pipes used in traditional dual exhaust systems. The single 3" outlet is fine as the dual tailpipe setup is merely cosmetic anyway. Any suggestions on this one? Should I stick to the 2.5" exhaust pipes and neck up the inlets on the muffler or use 2.25" dual pipes from the cats to the muffler? My 2000 S/C has the 4.6, K&N, airbox mods, and Superchips program.

 

Magnaflow makes a SIDO that can be reversed as well. I'd look for a dual 2.5" to single 3" muffler instead, and you'll want a 90 degree 2.5" elbow when you cut the OEM y-pipe out.

 

I just put the american thunder kit on my truck. I love it. It comes with a SI/DO muffler.

From this forum, I was expecting a very loud and annoying drown, and it's far from. There is a drown, but you can easily talk over it. Guess I'm use to my 2 previous mustangs with dual flows.

I have a friend who has a 2003 durango with the 5.whatever engine in it. ANd she went with a custom dual flowmaster setup. SI/SO 40 series mufflers and 2.5 pipe. Here stock setup was like ours. quad cats into a Y and single pipe the rest of the way. Her truck sounds like complete ****. On rev up/acceleration it sounds really nice and mean, but on rev down/decerlation it pops/pings, sputters, babbles, backfires.

I say that anything that didn't come dual, should be true dual.

The american thunder kit I have, has dual tips out the rear, and they smoke equally, so it looks like true dual. I would just get that type of setup instead.

 

Thanks for the input. I've been a regular "reader" of this site since I bought the truck new 5 years ago. Tried a number of different things that I found interesting and useful. Just never saw anything about the DI/SO muffler setup I'm going to try. I know how true duals look and sound as I've had numerous vehicles over the years with them; 69 Chevelle, 69 Olds 442, Plymouth 440, Impala SS, Mustang 5.0, to name a few. The truck is a daily driver and is used for back road 4X4. The dual tailpipes seem to be a bit of overkill for my usage and the single 3" pipe seems to be my best bet. The double inlet on the muffler would give the truck some better exhaust flow by elimating the factory Y that goes into one singe 2 1/2" pipe. I have a SI/SO Flowmaster Delta 50 on it now that I put on 5 years ago. It's been fine, not too much cab or external noise. Need to free things up a bit!

 

FWIW, I just put that exact muffler on my Explorer. (I needed the dual in, single out because of the OEM header's design) I love the sound on the Ex.... I've been curious how it would sound on the F-150.

-Joe

 

I've ordered the muffler and it should be in early next week. I'll post my impressions of how it works as soon as I get the installation done.

 

Finally got the installation completed yesterday......the muffler took a little longer arriving due to shipping problems. It took my local Midas shop, that I've been dealing with for close to 20 years, about 1 1/2 hours to cut and fabricate the pipes. I notice just a slight increase in interior drone now compared to the SI/SO Flowmaster 50 I have had on the truck since new. Expected a bit more due to the larger volume size of the muffler itself and the extra pipes.
The installation went without problems, only a slight "crinkle" in one of the four bends in the 3" tailpipe. Won't affect anything though. As I have only driven the truck last night around town for an hour or so, I haven't noticed any gains or losses. Just that grin factor knowing what I have done. My teenage stepson says it sounds like it has more "bass". Gives a more pronounced deeper sound to the system. I'm happy with the results as it cleans up the restricted factory Y-pipe and gives me dual 2 1/2" pipes into the muffler then into a single 3" tailpipe in the factory location.
I took a close look at the factory Y-pipe after it was cut off. Wow. Even more restricted than I thought. The drivers side pipe butts into the side of the passenger pipe with a flange that gives maybe a 1 3/4" hole for the exhaust to pass through. Not a very good design.
I'm happy, and would recommend this setup to anyone else. The only thing I might suggest is getting a pre-fabricated mandrel bent tailpipe from one of the name brand suppliers. My installer advised me that sometimes as the pipes get larger, it is a hit and miss thing for getting a crinkle in the bend, depending on the supplier of the pipe itself and its thickness. On mine, some bends were fine but a section of "softer" metal created the crinkle.

Good luck.

 

Something I neglected to do and it appears my neglect caused some temporary problems. The engine was running rough, acceleration was "spotty" and when coming to a stop, a couple of times almost stalled. I usually disonnect the battery whenever I complete any modifications, but this time I didn't, as it was one of those ten minute jobs that I just never got around to doing. Spent the first week running lousy then did the battery disconnect and this past week has been fine. No sputtering or stumbling, runs normal again. Just enough change in the exhaust flow to confuse the computer. Other than that, all is fine, sounding good and running fine.