I am planning to have a shop do this today, so I need some advice ASAP. I have a 2006 5.9 CTD and I want to straight pipe. What should I have the shop cut off? Keep the cat *or* just the muffler *or* cut both off. Will I have any codes come up? Will I get better fuel mileage and last will it do any and I mean any damage to the turbo *or* the truck. Sorry also need info on what drop in air filter to use. I will keep factory box but want increased air flow.

 

If I were you I would keep the cat on for legal and warranty issues. Just so you know, with no muffler, and a cat, my 04.5 was very loud and had bad drone at highway speeds. So much that I would occassionally put my hearing protection on cause it was driving me nuts! I would get a high flow muffler if I were you, unless you like REAL LOUD and don't tow.

 

Ok I think I understand. I do tow a 5th wheel so are you saying keep it as is.
Thanks
Dave

 

I guess what I am saying is if you like REAL LOUD, cut off the muffler. Geno's garage has a muffler delete pipe you can use to fill in the space. If you don't like REAL LOUD, get a high flow muffler and clamp it in there instead of the stocker. I like my Silverline a lot. I think Donaldson is another popular brand.

 

Got it. Thanks for the input

 

Keep the cat, just lose the muffler. You won't be sorry!

 

I got rid of both and it's GREAT, I don't get why people say it's to loud, unless you drive with the windows down, I can only hear the exhaust at WOT over my music. Even with 1,000lbs in the box it's not bad at all, i'm sure it will be quite load towing but I don't tow heavy often so i'm not worried. Straight pipe all the way Just FYI, cruising on the highway at 75 MPH you can't even hear the exhaust.

 

What year truck do you have? I swear mine was so loud that a couple times I put on the hearing protection that I use when running items like chainsaws, bobcats, zero turn mowers, and the like. That was with the windows up. It was so loud in the cab that I felt bad for people in the truck with me.

 

04.5 6 spd. It was only loud when 1 of the exhaust clamps broke at the front of were the cat was and most of the exhaust was coming out right below the cab, THAT was unbearably loud, but just straight piped I don't find it bad but I also rarely WOT.

 

It all depends on your openion of loude. All of my diesels and all of my brothers that we have ever had are straight piped, the only one that was a lil annoying was my 06 i have now, with a stock turbo we dumped it between the cab and the bed, that was annoying lol. i would say try it totally straight, if you don't like it add a muffler, i take the cats off of every diesel i own ( for off road use only ) :}

 

mine is straight duals and i agree with mocho, its not loud at all. When i first got the truck i cut the muffler of and i could barely tell a difference. So if you dont want to loud cut both and install a high flow muffler!

 

I did the 5" Magna flow cat delete system. It was pretty tolerable around town and on the highway. Loaded was another story. It was louder than hell. I went and put the 4" cat back on and drove it to the muffler shop to get it connected and it was quieter with just the cat and no pipe or muffler than it was with the whole Magna flow system.
I am going to try a 5" donaldson.

 

Well David, good luck. Looks like there are some differing opinions! Let us know what you end up doing and how you like it!

 

yupyup....just cut one off at a time. thats what i did at first

 

This is the filter I went with, it new on the markit. I will drill some holes in my air box also. http://www.amsoil.com/storefront/eaa.aspx

I ordered the MUFFLER ELIMINATION KIThttp://www.genosgarage.com/prodinfo.asp?number=ME-KIT-DG-04.5

and I bought a Steering Box Stabilizer. I will order this next week , Let me know what you all think. http://www.fullpulltowing.com/index.html