10v header: Downpipe

[David Vander Schaaf]

Thanks Javad for enlightening me!  By the way, did you tig weld or mig weld
your em?

I just got married a couple of months ago and am waiting patiently to buy a
house... actually I don't care too much about the house, just needs to have
a big garage and pole barn/workshop.  Then I can stop dreaming and start
working!  Would love to do a V8 swap into the 90q 20v... if Alex VG doesn't
beat me to it first. ;)  Actually, get busy Alex and show us the way!

Dave - GR MI
'90 90q 20v




> <<  My question is about headers and turbos.  I was under the impression
that
>  turbos generate too much heat for headers to stand up to, and that cast
iron
>  manifolds were preferred.  I know that my Porsche 944 turbo has a
stainless
>  header, but the turbo is quite aways away.  I am curious for your
thoughts
> on this.>>
>
> Well, yes, it is generally considered that cast iron manifolds are
stronger,
> but that does not mean a tube runner manifold cannot be even stronger than
> that if though is put into the design and construction of it.  You are
right,
> though, that a thin-walled mild steel header will self destruct in no
time,
> as the heat and expansion caused by a turbo are severe.  Even thin-walled
304
> stainless is not considered ideal, as it will weaken over time at the
levels
> of heat in a turbo application, over 1000 degrees!  Aircraft quality 321
> stainless is considered ideal, as it contains some titanium that gives it
> much better heat stability and strength.  In a thin walled header
> application, 321 is the material of choice, but its very expensive, about
> twice the cost of 304.  To build a header like mine out of 321 would have
> cost over $500 in just tubing!
>
> So, I looked for another material that would be suitable, and I found
thick
> walled hydraulic tubing, often referred to as WeldEls.  These are cast
steel
> elbows and drawn pipe that come in all kinds of shaped and sizes.  I used
a
> thick walled 304 stainless schedule 10 WeldEl, with a wall thickness of
.109"
> (16g is about .058").  These, because of their thickness, will hold up
well,
> while still not making a tank compared to the stock manifold.  When
finished,
> my header weighed about 10lbs.
>
> So, with the proper material and thickness, a header can be designed for
any
> application.
>
>  <<Keep up the great work... and may we, that only dream of building
similar
>  beasts, live vicariously through you and your turbo Audi. :)>>
>
> Get out there and do it!
>
> Javad
> 80tq.com
>