I am planning on doing custom exhaust inclduing a downpipe. Can the downpipe be made of normal exhuast tubing or do I have to get special materiaL or do Ihave to buy a downpipe already made?

 

Your best bet is to purchase one already made.. The research and development has already been done for you... Search the forums there is tons of info on your options. Most if not all of them are made of stainless steel.. and most are 3" diameter, with a few at 2.5"... Don't reinvent the wheel if you don't have to..

 

not trying to "reinvent" I am trying to save money. My exhasut shop can mimick the bends of a downpipe already made for the evo with 3" mandrel bent exhuast tubing. What I was wondering was if the standard exhuast tubing would be thick enough to keep the heat inside the tubing or do I need thicker tubing since it is next to te exhuast manifold?

 

If you get it done and find it's not sufficient, just remove it and heat wrap/seal it. Mine's stainless steel (not an evo, but same principle) but I'm not sure what grade.

 

Standard heavy Stainless 3" tube would be adequate, probably something along the lines of what is used on a Bus.... The only things I'd be cautious about is the location of the O2 sensor bung, and use thick flanges so they won't warp.

 

And don't forget to tell us how much it cost you, and if it fit right off the bat.. I'm curious..