So before the MBRP was delivered here, I had the stock muffler off and kept the cat on. Didn't sound much different from the factory setup...
I looked at several YouTube videos of people who just added a MBRP muffler to their truck and every one of them had a nice, deep sound to it.
Yesterday, the MBRP muffler came in along with the cat delete pipe (I was all excited). We put it on this afternoon and removed the cat...and it makes Cummins not even sound like a Cummins- it's terrible. I never heard any diesel sound like this; actually, it sometimes sounds like a gas truck. It's not any louder at idle than when it was all original and it's definitely not deep- it just sounds like ____; only way I can explain it. So, all the work and money for disappointment as of now.

Please tell me there's something I need to add or something.
Thanks.

 

im assuming that the exhaust pipe is factory size...which is probably why it doesnt sound the way you want...could try going to a 4 inch or even 5 inch piping. do you have a tip? i could 5 or 6 inch tip will make em sound like theyre gruntin a lil more too... good luck

 

Yeah, it's still the factory pipe size. I was told 5" pipe doesn't do anything except be bigger and maybe flow better so then I was quick to stick with the 4". I'm gonna be pissed if that's true though.

 

well the performance side of it is a different debatable issue IMO but for just the sound side of it i would say the bigger the better. and also the muffler is doing what it is supposed to do--muffle. take the muffler off so its straight and use 5 inch with a 6 inch tip and i think you would be well on your way to a low gruntin beast

 

agreed

 

Factory 4" isn't mandrel bent like aftermarket exhaust kits. You will notice a improvement in sound when going with a true 4" or 5" kit.

 

Just a suggestion, flip the muffler around so that it's running backwards (baffles facing the rear). I think you will like it much more. It's not as droany as a straight pipe but sounds very good.

 

I've already tried straight-pipe and that sounds worse.

I've read off of MBRP flipping it backwards will make drone inside the cab. But, if you're JUST comparing it to straight-pipe drone, then maybe...

I would hate to spend $350-500+ on the full thing and still be pissed.

Yeah, I figured that but I was looking for a deeper sound. I bought a muffler for my other truck and it made a deeper sound. I know not all trucks and mufflers are the same but you might see where I'm getting at.

 

Well you have the muffler so you might as flip it and see if you like it better. All you will be out is time.

 

Just my .02 I bought my 5inch straight pipe from Luke at Diesel Dawgs and I love it. Was easy to install and I get compliments and questions all the time about it. With the adapters im sure you could say and reuse your MBRP muffler so it would be a total los. Sorry to hear about your bad luck.