Steve,
Actually, by using the phrase "exact science" I meant it in the
colloquial sense that we do not have access to the equipment to test
every possible set of headers that are on the market to determine
which one is best under each one of our individual set of conditions.
Give that situation, we can make generalizations and selections that
will suit us just fine.
I'll be careful in the future not to confuse the issue and I'll stick
to the exactly provable.
Thanks for the correction.
Regards,
Jim
B9470139
---Steve Laifman <Laifman@flash.net> wrote:
>
>
>
> Jim Parent wrote:
>
> > Typical performance Ford books note that 1 5/8" primary tube headers
> > are a fairly close match to the port size and should work just fine.
> > If SS's are 1 1/2" I'd guess that's close enought so that it won't
be
> > your biggest issue. BTW, the same books normally note that primary
> > tubes oughta be about 30" to 40" long and that both selections are
not
> > an exact science.
>
> Jim,
>
> Actually, header designs are an exact science. Especially if you
want the low
> pressure wave in one exhaust port to help extract the next cylinder.
Ideally,
> they work like waves, one tube's low pressure helping extract the
next, and so
> on through the next cycle. This is the main purpose (other than
diameter) for
> headers. This extraction aid only works over a narrow rpm range, so
they are
> "tuned" for a specific engine and use. Unfortunately, only the
pro's can afford
> a different set for each race. The Tiger has little room for this,
anyway, so I
> wouldn't sweat any "optimization".
>
> Steve
>
>
> --
> Steve Laifman < One first kiss, >
> B9472289 < one first love, and >
> < one first win, is all >
> < you get in this life. >
>
>
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