[joelucci33]

What kind of differnce will i notice if I go to a bigger down pipe? and how big can i go with out having to change in housings?

 

[alfajay]

Should be able to do 4" DP. All it does is slightly lower EGT's. I heard 30-50deg. but not sure.

 

[strokin_early_99]

Yes, a 4" will bolt right up, you may need to bend the trans dip stick a little so it does not rest on the DP but it will fit. EGT's will drop anywhere between 50-100deg. It will make it sound a lot more throaty as well.

 

[nboeger4]

also keep in mind its kind of a pain in the a** to install a 4in downpipe.

 

[alabamafrog]

My 4" DP went in pretty easy, getting the factory one out took longer than putting the new one in. The biggest difference I noticed is a lot deeper and louder cab noise.

 

[DR. HVAC]

i found the easy way to remove the factory pipe is the cut it at the 90 bind then loosen it at the turbo and it falls out through the bottom

 

[Dirk]

4in down pipe is cake on a 99-03. The band can be tricky if it is stuck.

 

[CSIPSD]

also keep in mind its kind of a pain in the a** to install a 4in downpipe.

Maybe on a OBS installing a 3" is, but on a superduty a 4" is a 30 minute job...