I picked up a Nelson 86131M muffler for my 05 today. I had installed one on my 03 and liked it. I notice it has an opened chamber in the middle of the exhaust, about 1 1/2 feet in. Did my old one have that chamber??? Also, is the dome shaped side the outlet end?? Thanks in advance!

 

I know a lot of you installed this muffler. I'm installing it with the cat on. I don't recall my last one having an opened " cavity" in the center of the muffler. (I thought it was 4inch straight through??

 

yes the dome side is the outlet. Do not know about the chamber I have the donaldson with the cone in the middle.

 

Thanks rammv- i figured it would be the outlet since they use them on semis.(No arrows like on an ordinary muffler.) I'm curious about the wide opened chamber in the middle. It is straight through without baffles, just wondering if that big empty void in the middle is the same as they were a few years back, if it makes any difference...??

 

I need some advice. I read an ancient post on an old thread that said these mufflers Were "straight fluted" in the past. This new one I picked up is straight fluted except for about a foot or so of opened chamber in the middle. Will the opened space matter as far as EGT's or anything else?

 

The muffler does open up in the center. You can still see straight through it as well.
I put mine on without the Cat and I really like it. Passed the wife test as well.

 

Thanks for your reply! I had this muffler on my 03 and really liked the sound. I put the smaller version on my 05, and it's pretty loud going up hills with the trailer. I've grown tired of it, and I'm replacing it. Thanks again!