I replaced the cat on my truck with the front pipe from my pals 2003 LB7 truck and used a magnaflow 4" cat back system. Very happy with the results, not too loud but just enough to sound like you got authority.
i will be cutting out the muffler and welding in just a strait piece of pipe on a 05 tomorrow, leaving the cat and everything else stock. i did a cummins a while back and if its half as good as that turned out i will be happy.
Do a cat back and you'll be happy. Just cutting out the stock muffler helps, but you're still held back with the stock non mandrel pipe sizes. Getting a 4 inch mandrel and the straight thru muffler will help more with EGT's and spool up, and the sound will be quieter than cutting out the stock muffler alone too. If you have questions just call us and we will be glad to help you.
im not really sure why they even waste the money on a muffler on a these. besides a little lower tone at an idle i couldn't really tell much of a difference. i think it is the vains in the turbo changing that can be heard very well. like its been said before anyone looking for a diesel strait pipe sound should go with a cat delete pipe or a system that does away with it. my $.02
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