Building a Custom Header

[rousie13]

Well I'm getting a turbo soon and am going to design my own header for it. I have a couple questions though. What size piping would you guys use to contstruct the header? Also would you start 3" piping directly off of the end of the header or go 2.5" to 3". I'm not positive on the design yet, but I'm going to talk with a few guys on what design will work the best for my goals. I'm also making my downpipe and flanges for the pipes. Gotta love having access to TIG and MIG welders, CNC machine, bridgeport, lathe and tons of other stuff.

[LanceS13]

I assume by header you mean an equal-length manifold?
But what do you mean by 2.5" or 3" off the end of it? The manifold should terminate with the appropriate turbine flange.
As far as pipe size, remember the bigger the runner piping, the more volume has to be filled with exhaust gases before the turbo starts spinning. Also with more cross-sectional area, the gases will be moving slower so it hurts spool-up two-fold. I'm gonna use 1.3" ID piping for mine. Also, if you're utilizing an external/divorced wastegate, don't forget to include a wastegate bung/flange in your design.

[meme]

here is my old manifold
http://www.psijunkies.com/images/jvh22a/turbosetup/newmanifold/2002_0418_151939AA.JPG

http://www.psijunkies.com/images/jvh22a/turbosetup/newmanifold/2002_0412_101403AA.JPG

http://www.psijunkies.com/images/jvh22a/turbosetup/DSCF0003.JPG

[meme]

here is my current project. runner 2 might hit the brake line. but i'll test fit it later this weekor next. after i do the 5spd swap.

[meme]

another angle go to mcmasters.com and use these part numbers
-43425K151
-7750K115

i think they are 1.5 ID this is on a ka motor

[mbmbmb23]

This place has SS tubing for sale. Seems the 321 alloy has better heat resistant properties than the 304...but its more pricey.



http://www.burnsstainless.com/321tubing/321tubing.html



-m