What is the difference between the 2003/2004 years and 2004.5/2007 years exhaust ?

 

The outlet elbow on the turbo is 3.5" on the 03-04s, and 4" on the 04.5-07s. Alot of 03-04 guys try and find the elbow off of a 04.5+ to replace thiers. Then you will be ready for full 4" exhaust, and you would buy an exhaust kit for a 04.5+.

 

Gotcha ! I thought it had to do with the exhaust flange but looked similar to me.
Now I know. Thanks

 

You will also need to get the clamp that goes from the elbow to the exhaust. The clamp that holds the exhaust elbow's on is the same on both trucks.

 

I've seen some pics of 4" DPs on some of the aftermarket exh. sites that I swear look like the top bend is made to clamp directly to the turbo and skip the cast elbow. Is that true or am I just imagining things. I built my own DP that way but it was a tedious job, torching out a flange and grinding it to fit the turbo. Craig

 

i had my local diesel parts shop call mbrp about replacing the 3.5 inch cast exhaust part with 4 inch. mbrp says that is not a good idea, that the turbo needs that back pressure to work correctly, but i see a lot of guys doing it. can anyone give some facts to help?

 

I can't help you with that one cuz the stock turbo was the second thing to go - the asthmatic muffler was first. But I can tell you the stock 03 turbo is LOUSY! After the A2K I built the 4" DP and added a 4" glasspack/resonator (slightly choked with louvers inside) right at the end of the DP and max egt stayed the same. So whatever restriction the louvered glasspack added was countered by the full 4" elbow and DP. So, I"d have to say it helps with some turbos. Craig

 

You dont need back pressure. Some exhausts do connect right to the turbo skipping the cast elbow.