I'm not saying regardless of port work to keep the butterflies... It entirley depends on what the end result is that your chasing, I myself don't have the butterflies in my setup..
But the scientific evidence is there, small amount or not..
But remember we are discussing flow here, not airspeed so the points are entirely based on flow rate information. Although airspeed is relative, it is not being discussed..
The poor exhuast side is always forgotten about, however as far as the butterflies are concerned they have no direct influence whatsoever on the flow rate of the exhaust, as it is on the directly opposite side of the cycle..
R34 - The increase in flow on the exhaust side would be more attributed to the greater surface area of the ports, I have increased the valve head diameter from 28.15mm to 30.65mm.
I have some photos floating around I will dig out when i get a chance, work is pretty flat out at the moment..
At the end of the day, people will do what they feel is the right thing to do, regardless of advice they source.
Real, tangible evidence is far more credible than heresay and I am happy to provide my data.
As a personal observation, I seem to be the only one providing it (experience is also key, don't get me wrong), does anyone else have this sort of realtime data to add, I would like to compare for the good of the community