Intake Runner Length

Bruce Plecan nacelp at bright.net
Wed Feb 3 03:03:47 GMT 1999


-----Original Message-----
From: Van Setten, Tim (AZ75) <Tim.Van.Setten at CAS.honeywell.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, February 02, 1999 4:47 PM
Subject: RE: Intake Runner Length

I worked at an R+D shop, and for a while Ollie Morris (one of the great of
manifold designers), and find Smokey Yunick's quote of "square ain't as bad
as
it seems" (or words to that effect) meaningful.  While many ports look like
beautiful
sculptures, sometimes it's just better to take you licks, and be done with
it.
Specially with a dry manifold.  Considering at 6,000 rpm from butterfly to
intake valve the "air" is only in the intake for like .008 (and possibly
much lesss) of a sec. it ain't there long enough to estabish boundry
layers/laminar flow enough to matter (for other than all out race
applications).  Worry about the bowl, and valve,
the most.   Specialy if were still talking about a turbo VW.  Then we can
get to keeping the total valve diameters not to exceed 85% of the bore, or
shrouding
gets to be an issue (non-hemi heads)..  Sir Harry Ricardo, just realised I
hadn't mentioned him in two weeks.
Cheers
Bruce          Well, if the smoke alarm batteries fail, the Fire Dept is a
distant
                  second for a Food Timer.  Gotta teach Doc to use the
microwave.
                  Least we got new windows in the Kitchen outta the deal.


> I can understand air speed
>in the runner, etc., but where it goes out the window for me is when you
see
>the runner, where it attaches to the plenum, is a square corner!  A lot of
>plenum / runner combinations are shaped like a "T".  Believe me, I'm not
>trying to make an issue out of this, just trying to understand and make the
>best setup feasible.
> Thanks.....Tim.





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