[Oscvrh]

I recently picked up my 3rd gen cummins and where I live (Colorado) diesels require to pass emissions in order to get plates for the truck. My truck has a 4 inch turbo-back exhaust with a aero muffler on, no catalytic converter, so I'm thinking of having a cat welded on to the exhaust (this one). Is this something possible to do? Will I experience anything bad by doing this ? You guys think this will pass emissions ?

 

[4everlearning]

You can absolutely have that installed. I don’t know your state’s emissions laws. That cat won’t pass in California where I live.

 

[Oscvrh]

You can absolutely have that installed. I don’t know your state’s emissions laws. That cat won’t pass in California where I live.

I live in Colorado, where usually we don't have to worry about this, but the county I live in is the California side of Colorado haha so they require emissions on diesels every year.

 

[4everlearning]

Check your local laws and find out if you need a carb compliant cat. My guess would be that you don’t

 

[Oscvrh]

Check your local laws and find out if you need a carb compliant cat. My guess would be that you don’t

I've been searching and searching all day but I can't seem to find anything on those restrictions. Usually all I find is that they will perform a exhaust smoke opacity test on a dyno to simulate "highway driving" and possibly a visual check to see if there is a cat there.

 

[brutal]

Colorado diesel emissions are done at private authorized shops. Smoke test on the dyno, visual, and check for codes.

My 04.5 passed with flying colors every 2 years while temporarily running stock tunes with both an Edge Juice and later a Banks Economind. I almost always set them to stock, but may have forgot once or twice and it still always passed. Truck had a S&B CAI and a few other intake/exhaust mods and I never even got a raised eyebrow. They don't care as long as it passes the smoke and has the required emissions parts installed. All of these shops are doing performance work too.

Are you sure your 03 needs a cat? My 04.5 HO was (as I recall) the first year they put on a passive cat. You could find a dead one in a pick and pull, gut it, and weld it in place and I think it would pass.

 

[Oscvrh]

Colorado diesel emissions are done at private authorized shops. Smoke test on the dyno, visual, and check for codes.

My 04.5 passed with flying colors every 2 years while temporarily running stock tunes with both an Edge Juice and later a Banks Economind. I almost always set them to stock, but may have forgot once or twice and it still always passed. Truck had a S&B CAI and a few other intake/exhaust mods and I never even got a raised eyebrow. They don't care as long as it passes the smoke and has the required emissions parts installed. All of these shops are doing performance work too.

Are you sure your 03 needs a cat? My 04.5 HO was (as I recall0 the first year they put on a passive cat. You could find a dead one in a pick and pull, gut it, and weld it in place and I think it would pass.

Hmmmmm if anyone could chime in and verify that. I hope that’s true I really love the sound of the truck’s setup right now

 

[brutal]

I checked again and every thread that I can find, including one from here, asking about cats shows (except CA trucks) they were added to 3rd gen with the 04.5 HO to meet Fed emissions.

03-04 SO/HO no cat.
04.5 HO and newer = cat

2003 cummins catalytic converter - Google Search

I'm not sure how you would be able to find out for certain, but I'm 99% sure you don't have/need a cat unless it was originally a CA truck.

 

[Oscvrh]

I checked again and every thread that I can find, including one from here, asking about cats shows (except CA trucks) they were added to 3rd gen with the 04.5 HO to meet Fed emissions.

03-04 SO/HO no cat.
04.5 HO and newer = cat

2003 cummins catalytic converter - Google Search

I'm not sure how you would be able to find out for certain, but I'm 99% sure you don't have/need a cat unless it was originally a CA truck.

Please educate me, as I'm still new to all these terms. What does SO and HO stand for or mean ? I see those all over this forum.

 

[99grinder]

Please educate me, as I'm still new to all these terms. What does SO and HO stand for or mean ? I see those all over this forum.

Standard output and High output. Referring to the rating of the engine from the factory.
How do they expect you to get the truck to the inspection station without plates?

 

[rghavana]

03-04 Federal emission trucks did not have cats.
Need to id which truck you bought enter vin at FCA RAM

 

[Oscvrh]

Standard output and High output. Referring to the rating of the engine from the factory.
How do they expect you to get the truck to the inspection station without plates?

Dealer gives you a temporary plate that is valid for 30 days

 

[Oscvrh]

03-04 Federal emission trucks did not have cats.
Need to id which truck you bought enter vin at FCA RAM

Just looked it up, we’re good boys 👍🏽

 

[Danderson]

Hmmmmm if anyone could chime in and verify that. I hope that’s true I really love the sound of the truck’s setup right now

I know of 3-4 California guys who went to AZ and Nevada to get used 03-04 Ram HO's. You could bring them in with 7501+ miles legally. I believe the cat has to be in the factory location too.

 

[4everlearning]

I know of 3-4 California guys who went to AZ and Nevada to get used 03-04 Ram HO's. You could bring them in with 7501+ miles legally. I believe the cat has to be in the factory location too.

If they are a federal truck, they do not need a cat, even in California.

 

[Danderson]

If they are a federal truck, they do not need a cat, even in California.

That's correct. I was referring to the op's truck. Sorry for the confusion.