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On my 2004.5 ram diesel quad cab short bed I want to remove my Cat and Stock muffler. I am putting a aero 4040xl in place somewhere. now the question is do i put aero4040xl where stock muffler was and get a cat delete pipe or do i put aero4040xl where cat was and get muffler delete pipe? Does it matter which one I should get? is 1 cheaper than the other? Is aero4040xl same length as stock muffler?[/align]

 

The Aero is straight (not offset). It would be easier I would think to put the Aero where the Cat was and get a muffler delete pipe, which is offset, for the muffer.

 

I plan on gutting my cat and I have the Aero 4040xl on the way also. I am putting it where the stock muffler is.
I thought long and hard about what to do with the cat. Chances are there will never be emissions testing in Texas for my truck. Even if there will be some day, I can find a cat at a junk yard. I know they are $1000 new but I'll bet they can be found much cheaper if I ever have to replace it. So I plan on just gutting it so that I don't have to worry about the dealer bitching about it not being there should I ever need warranty work.

 

I've seen other threads about putting the Aero where the muffler is, it is possible but more of a headache because of the offset in the tailpipe dictated by the stock muffer.

 

Doesn't really matter, other than preference.

Some people say it makes more noise in the cab if it's where the cat was. Mine is under the cab where the cat was and then I have a 36" Diamond Eye flow-though where the original muffler was. The Aero was just too loud for me by itself.

Eventually, I'm gonna take the Aero out of there and just pipe that section. I don't know if it's just me, but the Aero seems to make it sound a bit "rice'ish". Not worth the price, in my opinion.

 

Curious, which Aero do you have the 4040 or the 4040xl?

 

4040XL...the resonated version.

 

I am interested in doing the same thing. But..... What is removing the cat going to do the the fuel milage. I think someone on this forum said oncehe removedhis cat, the mileage went down like 1.5 mpg. Not doing anything the the truck, except a aero 4040xl, and removing the cat. Will mileage go up,down, or stay the same?

 

The cat is not a huge restriction in this exhaust system. The thing is HUGE and pretty much straight through. The biggest restriction is the stock muffler. The worst thing the cat does is make bunch of heat and changes the exhaust smell to that of propane, rather than what a diesel should smell like.

Steve said that his mileage dropped when he removed his cat, but went back up when he installed the Aero.

My personal opinion is that the muffler has more to do with this than the cat does.

One thing about the cat is that it does smooth out the exhaust tone a bit. Not necessarily quiet's it down, but smooths it out a bit.

I would leave the cat and change the muffler. You can always remove the cat later and replace with a section of pipe later. That's the cheapest / easiest way to experiment a bit.

Also, don't buy a whole exhaust system, just get a muffler replacement (may have the offset pipe already). The rest of your exhaust is already 4" and is more than enough.

 

I found that by removing the cat you will drop the egt's a good 50F to 100F. It's as much a restriction as the muffler is. One reason to replace the whole exhaust system is to get rid of the piping that will rust out. It may take a while but, if you like I, live where the roads are salted during winter, it's one less thing to worry about. Just make sure if you do go stainless that it T304. Just something to think about.