[urq] Re: 10 vT EM?

JShadzi at aol.com JShadzi at aol.com
Tue Apr 30 12:12:41 EDT 2002

[ Picked text/plain from multipart/alternative ]
Scott, when developing my header, I took this into consderation as my past
experience with the AS headers also showed me this.  I will note, however,
that with my past experience with the TA cars, and crates of their spare
parts, not all AS headers shared this design.  In fact, there were many spare
headers that used no expansion at all, they appreared to be 16g stainless,
and had evidence of multiple repair in the collector area due to expansion
related cracking.

Due to the additional effort and expense of using slip joints, I decided to
use a very heavy gauge material for my design, therby averting the cracking
problems with thinner materials.

I used Schedule 10 hydraulic fittings, 1.4" ID, 304 stainless.  Though 304
stainless would be inferial in this application is thinner gauges, it is more
than sufficient in this application, having a wall thickness of about 1/8".

So far, with about 10k miles of hard driving, there have been no expansion
related problems with the header.  Also, having the individual flanges gives
the header the opportunity to move quite a bit as opposed to one solid
flange.  In about another 10k miles I'll pull off the header, see how its
held up, and go from there, but I'm quite happy with the way its held up thus


> Looking at pix of both your header setups vs the audi sport 10vt and 20vt
> headers, one think I notice that A./S uses is sliding joints on the
> collector pipes to accomodate the heat expansion of the manifold and
> runners.  Corky Bell references it, and several of the mitsu applications
> have it as well.
> My understanding of this design, is that it reduces the chances of heat
> cracking to almost nil.
> Any reason you guys aren't going this route?
> Scott J>>

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