8.1l Muffler

[Ezrider_92356]

im looking at putting a new muffler on my truck right now its bone stock, i dont want anything loud but i would like it to sound like i have a v8 under the hood insted of sounding like a hybrid...lol but like i said i dont want loud just a little rumble while standing outside the truck i defently dont want it to drone when towing. i it would be nice to free up a mpg or two as well, is it better to dual it out from the cats back, its already dual 3 inch to the muffler and then single 3 inch out the back. is it best to keep this setup or run dual 3 inch out the back

[04JJHD]

Most people like flowmAster 50, magnaflow, borla, or flo pro. I have a flo pro hd big oval #2505 on my 6.0 that is dumped right after the muffler. Because it is dumped it drones slighty from 1700-1900 rpm's. I had it hooked up to the stock tailpipe but it needed more sound. On the highway you can't even hear it, if it helps any I have 4.10 gears

[Ezrider_92356]

yeah i would prefer not to hear it on the highway, i want it to sound like a truck insted of being dang near silent like it is now. would like to be able to roll the windows down and have it sound like a truck instead of a hybrid. and certainly don't want a drone when pulling i can spend 3 days on the road sometimes driving 800-1000 miles a day pulling a trailer.

 

besides having some tone i would like good flow. also if i install test pipes in place of my cats will it throw a CEL?

 

did your system drone at all before you dumped it?

[04JJHD]

it did drone i tiny bit but this is with the windows up, but with the windows down it didn't phase me at all. They also have different sound levels, if you go to their website flopro.com and click on the hd big oval it will show a chart on there. I have the 2505 which is the loudest they offer. I know this is such a tough subject and I researched this subject for a year trying to get an answer, and I think in my oppinion the flo pro is the best way to go if you do not want drone. Just remember that everybody has a different definition of drone. I had my wife drive it before I took the tailpipe off and dumped it and she liked it alot. Then she drove i after and didn't like it but she got used to it and now she loves to drive it. I myself can stand a little bit of drone

[04JJHD]

these stock systems flow really well and unless you are making like 500 hp there really isn't going to be much difference between mufflers, maybe a couple horse here or there but to answer your question on the cats they will prolly throw a CEL but I'm not sure. The cats flow really well on these trucks as well. Unless you want duels just change out the muffler and call it a day. the sound of the flo pro I have is just a little bit deeper than stock and kinda like a flowmaster 50 without that raspy-ness

[Ezrider_92356]

i cant seem to find any mufflers that are dual 3 inch in with single out anyone got any sugestions

[8.1HD/ALLISON]

If you are wanting single out, you could get a y pipe and run the duals together before the muffler. I haven't looked too much at mufflers. Also if you have the 8.1 L I don't think you have o2 sensors behind the cats. If there are no o2 sensors behind the cats you can cut them off without a CEL. But as stated before they flow well, I would leave them be. But thats just my opinion.

[Ezrider_92356]

i think if i was to use a y pipe i would probably do dual mufflers and then use the y on the back side, or use a dual in dual out muffler and y it on the back side, seems flow would be better. being that its dual 3in to the muffler should i make my single out 3.5 or maybe even 4in i think it would still hold enough back pressure for a 496ci motor. if i were to dual it i would probably run dual 3 inch all the way out so with a single pipe seems 3.5 would be just fine.

[bbyukonxl]

i think if i was to use a y pipe i would probably do dual mufflers and then use the y on the back side, or use a dual in dual out muffler and y it on the back side, seems flow would be better. being that its dual 3in to the muffler should i make my single out 3.5 or maybe even 4in i think it would still hold enough back pressure for a 496ci motor. if i were to dual it i would probably run dual 3 inch all the way out so with a single pipe seems 3.5 would be just fine.

 

 

i have an 03 yukon xl with 8.1. i did a magnaflow dual 3" in to single 4" out and it works great.sounds good and not to loud.

[yukon25008.1]

i think if i was to use a y pipe i would probably do dual mufflers and then use the y on the back side, or use a dual in dual out muffler and y it on the back side, seems flow would be better. being that its dual 3in to the muffler should i make my single out 3.5 or maybe even 4in i think it would still hold enough back pressure for a 496ci motor. if i were to dual it i would probably run dual 3 inch all the way out so with a single pipe seems 3.5 would be just fine.

 

 

i have an 03 yukon xl with 8.1. i did a magnaflow dual 3" in to single 4" out and it works great.sounds good and not to loud.

 

 

 

you realize your yukon has a 4l80e tranny..not an allison, it might be a 4l85e but i dont think they went in until 04