Hello Mech
I would just like to reword and clarify what you have indicated about the drop off in efficiency with Wide Open Throttle (WOT).
You state that carburettion (presumably direct injection and carburettors) increases the mixture richness at WOT, and this provides needed extra power but reduces efficiency. You also indicate that at some point below WOT there is no vacuum, and that this is the point of maximum efficiency.
So if I have this correct it seems that:
- the narrowest point in the inlet flow is the valve(s);
- as long as upstream there is no smaller choke area than this valve choke point, then there is zero vacuum;
- the throttle is open to provide this valve choke area at say about ¾ throttle, which gives zero vacuum for this and any larger throttle opening;
- opening the throttle over this ¾ position does not result in additional airflow, but the fuel supply system does increase the amount fuel added to the air.
If this is correct then it indicates that a relatively simple mod to ensure that efficiency is not compromised by using WOT would be to restrict the throttle so that it opens to a maximum of this ¾ location. This would reduce optional performance but would result in a simpler overall regime, ie if accelerating put your foot to the floor (to now give ¾ throttle).
Would this be a correct interpretation or have I messed something up?
Thanks