Anyone remove the catalyst from a Cat C-7?

[Longroad]

I noticed that my new to me RV has a catalyst exhaust, I was just wondering if anyone has ever removed one a replaced it with a standard exhaust. It is a 2005 C-7 350hp. I noticed that the thing must have gotten hot at one point since the adjacent basement storage has melted carpet. I have placed some heat shielding there, but maybe removal of the catalyst may make that problem a thing of the past and maybe even let the engine breath a little better.
Thanks

[Longroad]

Thanks

[aztortuga]

lONG ROAD, had exactly the same situation with my 2005 c7 350 hp. Excess heat generated around the muffler and was heating up the bedroom floor above the engine. It actually was charring the wood. Put a solid material above the muffler area for better insulation and later removed the large particulate muffler and replaced it with an aero 5050xl. The new muffler is definitely louder but I did get less heat retention, slightly improved performance and slightly improved mileage. I am satisfied with the results. If I did it over, I might look at some other mufflers which may give the same performance result but a little less noise.

[Longroad]

Thanks for all the replies. Definitely something to consider.

[Dutchstar02]

The catalytic converter in out CAT 330 (02 Dutch Star) was inside the muffler. It broke off and was rattling around inside. I replaced it with a regular muffler. The emission test results are actually lower without the converter than with. The unit is checked every 2 years. The engine runs cooler, the mileage has increased and there's no difference in the noise level. The replacement muffler was about 40% of the cost of an OEM.

[down_home]

Our 05 C7 came without the cat but after the dealer wrecked it they put a muffler with cat on it. It cuts power.
Many people have gone with Aero mufflers but they are loud. They do reduce bacck pressure and help mileage and power. A stock fuller for an 04 05 05 without the cat would seem logical and should just replace it.
I have not read of anyone doing it.
Some time ago there were two or three threads, along the way about mufflers and caats for the C7 and others.

[FIRE_UP]

carringb wrote:
Being in California, most likely that's a no-go. In fact, that may be the only reason yours came with a cat in the first place.

In CA, the only diesels are annually tested are 14,000 GVWR and under. They do not test the ones over that. I know 'cause I went through all that. Now, there are parts of the country that do test the larger diesel engines, Phoenix and Tucson AZ come to mind. Now, all of this could be wrong but, that's the way it was just a short while ago, when we purchased our '04 Itasca Horizon, 36GD with the C-7 330HP CAT.
And no, it did not come with catalyst in the muffler like other year models did. I removed that monster muffler that came with it an installed what's called the Aero 5050XL Stainless Steel straight through muffler. Now, long story short, I got pretty close to no benefit from doing that expensive change-out. All I got out of it was a noisier motor. What a pain in the a$$.

Anyway, in an '05 model, I'd bet quite a bit that you could hack that catalyst muffler off and install one like mine and, that engine will run just fine. However, I'm certainly no expert on this. If I might make a suggestion, get a hold of Brazels RV in Washington state, and consult them about what you might want to do. They've done quite a bit with the infamous C-7.
Scott

[ScottG]

You'll find there is no gain to removing it. The exhaust is designed to flow perfectly well with it and it's not much of a blockage anyway.

[carringb]

Longroad wrote:
I don't believe that they have yet instituted smog tests on large motor-homes in California. I would definitely hold onto it, in case they did. I do know that it wouldn't make CARB happy, but only bicycling makes them happy. I appreciate your comments though.

Dealers are not supposed to work on vehicle's with modified exhausts, so if you ever had a break-down, they could suspend repairs until the exhaust system is repaired. That's how its supposed to work anyways. Smaller independent shops might not raise a fuss. A certified CAT dealer probably would. So... could add some hassle if it ever broke down.

[racecarfan]

Longroad wrote:
It is not a DPF, just a catalyst muffler. DPFs were required on all 2007+ motors.

right gotcha now
understood

Thanks

[Longroad]

It is not a DPF, just a catalyst muffler. DPFs were required on all 2007+ motors.

[racecarfan]

Longroad wrote:
I noticed that my new to me RV has a catalyst exhaust, I was just wondering if anyone has ever removed one a replaced it with a standard exhaust. It is a 2005 C-7 350hp. I noticed that the thing must have gotten hot at one point since the adjacent basement storage has melted carpet. I have placed some heat shielding there, but maybe removal of the catalyst may make that problem a thing of the past and maybe even let the engine breath a little better.
Thanks

my friend has a 2005 C7 and it has nothing of the sort on it? I thought the first years of the catalyst stuff stared on late 2007 models (at least cummins did)

[Ductape]

I am by no means the exhaust police- just understand the consequences and expect the next purchaser if a dealer to require a signed statement that the emissions systems are intact. That's becoming common.

[Longroad]

I don't believe that they have yet instituted smog tests on large motor-homes in California. I would definitely hold onto it, in case they did. I do know that it wouldn't make CARB happy, but only bicycling makes them happy. I appreciate your comments though.

[carringb]

Being in California, most likely that's a no-go. In fact, that may be the only reason yours came with a cat in the first place.