Inlet manifold runner length

[Bruce Plecan]

-----Original Message-----
From: Stuart Bunning <stuart at kenelec.com.au>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, September 27, 1998 8:08 PM
Subject: Inlet manifold runner length


>I am in the process of making a custom EFI inlet manifold for a straight
six.
>I will be using a common plenum and a single throttle body or possible two
>throttle bodies not sure yet.
>Can anyone tell me the correct way of calculation the inlet runner length.

At the bottom of the DIY_EFI home page is an area for calculations,
and one of them is for runner lenghts.
>
>I assume inlet valve to plenum. Or is it inlet valve to throttle body this
>calculation will add a extra few inches as the plenum is usually a few
>inches wide. After the throttle body there will be a length of about 20
>inches of ducting to a airbox. I assume this is not relivent.
>
In some testing I did was best to keep this volume .5 to .75 engine
displacement.
Bruce