I have a stock exhaust, and purchased a cat delete pipe. I do not know for sure if it helped anything. But when you take the cat off and try to look trough it and you cannot see any daylight, well it has to help some how??? Muffler delete is next
I first installed a muffler delete pipe and noticed a deeper throated big block sound from about 2300 rpm and up.I then deleted the kitty and could then hear a little more of the turbo whistle.Out side of the truck it sounds a little like an F-16.Inside the truck you can hardly tell the difference. I will hang on to the cat and the muffler so if I care to sell the truck later on. I don't live in the middle of nowhere Idaho but I can see it from here. And for the most part this state could give a rats fanny less about the feds.
Everytime I read posts about the 6.0 exhaust turbo whistle it makes me miss my 2006. I had a MBRP 4" turbo back exhaust with CAT delete. That thing whislted like a 747 preparing for take off... and once you stomped on it sounded like a big block from hell! In my opinion, its the best sounding exhaust noise of any car/truck I have ever heard. I have tried with the 6.4 to replicate the sound... but it just doesn't come close. I have a AFE intake, 4" ceramic down pipe, stock exhaust with cat/dpf delete. It makes some noise, but no real whistle. When I stomp on it that big block noise comes out a little bit.
I removed my cat about 3 months ago with a cat delete pipe. You can definitely hear the turbo whistle. I did keep my cat you never know even here in Fl. So if you remove it KEEP IT!!! (Just put the cat to sleep in your garage)
It will NOT increase your fuel mileage! If anything, it will DECREASE it....... WHY???? YOU ASK???? Because you will keep your right foot firmly planted to the floor so you can listen to it. You will also wear out your right hand rear window motor running it down so you can listen to it reverberating off the sound barriers!!!!! LOL
After reading a thread on this i took it in too buddys shop got him too punch it out , he said it was 90 percent plugged , turbo sounds cooler now better midrange power better highway millage , gonna add banks turboback soon too " waunder how many of these things are plugged without us even knowing lol