The turbo header

Because I wasn't prepared to shell out the ridiculous amounts of money commonly charged for 4A-GE turbo manifolds, I decided to make my own. There's one little problem - I still have to learn how to weld. Good thing my friend Bjorn agreed to help. I do have to learn welding myself, so maybe I will try the easy parts myself, after some practice on scrap metal.
[ UPDATE : I did get to learn how to weld. It's actually quite easy with a steady hand and after some practice. Hardest part was I probably used too dark eye protection. Can't see a thing thru that stuff. The weld itself will light up, but you can't see much of what you're welding. ]

I wrote down a few demands:

  • Has to fit in engine bay.
  • Puts turbo in convenient place for plumbing and clearance.

    • and a few wishes:

  • Good flow without reductions.
  • Nice equal length header type design for quick spool-up.
    • As far as I know, AE92 engine bay is the same as my AT160 engine bay, and mine has the following items close enough to cause trouble for either the manifold, the turbo, the downpipe or associated plumbing:
    Radiator, engine block, oil filter, front engine mount, oil cooler lines, PS pump, distributor, starter.
    That's a lot, eh? You'd almost think the car was never designed for a turbo. Oh wait, this IS a custom install.

    I started by obtaining flanges, one for the 4AGE head and one for each side of the turbine housing of my turbo (a Garret T25 off a '96 Eagle Talon TSi AWD). The exhaust manifold gasket dictated 38mm runner diameter, the turbine flange is 55mm (in), 63mm (out)

    Construction

    Because this page was getting a bit long, I split it up into two sections.

  • the Collector

  • the Manifold

    • Costs

    Manifold :

    Flange turbine inlet  $20
    Flange head$25
    8 bends 38mm$50
    Resurfacing (even 10mm flanges warp)$50
    Countless hours$0
    Total$95

    Downpipe :

    (unfinished)
    Flange turbine outlet$20
    Pipe bends$15

    Things I bought but didn't need :

    Flange T25 (didn't fit - not for Mitsu I guess)$12
    4 bends 38mm (bought too many)$25
    10ft 38mm straight pipe$7

    I gave most of that along with an extra head flange to the guy who did the welding for me. He's going to do his own 4AGTE soon.