Inlet manifold runner length

[Stuart Bunning]

Hi All

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.

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.



<--- Head
------------|
--------,   |
        |   |<--- Plenum
--------'   |
--------,   |
        |   |
--------'   |-----
--------,   |  |
        |   |  o   Throttle body
--------'   |  |
--------,   |-----
        |   |
--------'   |
--------,   |
        |   |
--------'   |
------------|
   ^
   |

Runners







Best Regards,

STUART BUNNING
SALES ENGINEER
KENELEC PTY LTD

23-25 REDLAND DRIVE
MITCHAM VICTORIA 3132
AUSTRALIA

PHONE:  61 3 9873 1022
FAX:    61 3 9873 0200
EMAIL:  stuart at kenelec.com.au
WEB:    http://www.kenelec.com.au/