Bean Bandits Levin 'Globetrotter'

[NoHachi]

My experience: skip the calculations and just make it as big as possible. I've done hand calcs, ran simulations on CFD programs coupled to engine simulating software etc. The influence of runner length is pretty accurate, but plenum volume just gets lost in the noise. And that was on a pretty straightforward single cylinder engine..never mind 4 cyls.
The installed effect really needs to be measured. We made a nifty little variable volume plenum and determined the volume where an increase in volume did not increase VE.
A far bigger influence was the design of the plenum and ancillaries themselves! Smoothnes, radius etc etc.