If this is in a faq that I missed then I'd appreciate a pointer.

I am trying to find out what kinds of emissions, restrictions or other changes are in my 2006 Ram with 5.9 Cummins.

I read yesterday that somewhere after 2004.5 a new version of the engine was used which was quieter? Had something to do with the combustion cycle?

Take say, a 2003 model. What other things have been added up to 2006? I think all the motors were 325 hp after 2004.5, correct?

BTW, this is a California truck.

I mainly want to know if there's anything on there that was added for some new emissions thing that I might want to consider modding for "off road use"

 

There were a few different engines, my brother-in-law's '05 has the 355/610 motor. My '03 has th 305/555.

 

All the emissions junk came in 2007.5 model year trucks. Luckily I have an 07.

 

Just a little correction, but the 05 has a 325/610... just nit-picking

 

04 added EGR and o6 added more..lol, I believe also the comession was played with in 05-06, but the hp numbers varied depending on HO engine or base model.