Alright, I'm looking into buying a new exhaust for my 04 Cummins. I am leaning towards a 5 inch straight pipe. But I pull a camper. Got a couple of questions. How loud is the drone with a 5 inch straight pipe inside the cab? I want loud outside the truck but not so loud in the truck you can't hear yourself think. Are their any set ups with mufflers that produce loud sound but not loud drone? I have heard flo-pro makes a good set up with a muffler Thanks in advance

 

Any particular reason for the 5 inch? A mandrel bent 4 inch is more than plenty and will easily handle up to 500 hp. Exhaust velocity is quite speedy with a 4 inch which helps with exhaust scavenging. Exhaust velicity will suffer a bit with a 5 inch and you will lose a bit of torque, but it looks and sounds cool ,deep and throaty ( sounds ****-ish). If your gonna run twin turbos or a rather large turbo with serious mods, then a 5 inch will serve you well. you can get price quotes from vendors on this site. FYI

 

Oh BTW, a straignt pipe 4 inch and 5 inch is gonna be loud especially when hauling and towing. Not so much in the cab with windows closed, but crazy loud outside. More than enough to get the sound police to notice you. A good flow-thru perforated muffler will give a really good sound without the overkill.

 

I have a 5" MBRP straight piped system on my LMM. It's not too loud for me and a lot quieter than any straight piped-no muffler gasser I've ever owned.

 

Yeah, I dont know what it is about the straight piped diesel v8s being so quiet. when I had my Ford 6.0 PSD, it was straight piped and it sounded great and was not that loud, BUT when I first straight piped my current CTD, it was rediculously loud. And when towing my travel trailer, it was just stupid loud. An 11- hour road trip pulling my travel trailer was more than enough reason to muffle it.

 

Unless your looking to do big mods id say stick with 4". I have kind of a hodge podge setup - flex pipe from turbo- where cat met oem muffler, replaced the OEM muffler with a no name flow through glass pack 26" with stock tail pipe and it's exactly what I wanted. It has a nice throaty sound outside, inside I can't hear it over my turbo unless I really get after it. Quiet enough not to make the neighbors angry but loud enough to let them know I'm a couple blocks away. Performance wise from losing the OEM muffler I have gained about 1mpg