Intake Runner Length

[Ord Millar]

Bruce,

can you explain the 85% diameter thing?  It's not fitting into my brain too
well...

Ord

-----Original Message-----
From: Bruce Plecan <nacelp at bright.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, February 02, 1999 10:52 PM
Subject: Re: Intake Runner Length


>
>-----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.
>
>
>