Ok here's the conclusion I've reached:
+ reduced pumping losses from throttle position = more efficient
+ improved thermodynamic energy transfer = more efficient
- higher load to compensate for lower output = more fuel = less efficient
- lower dynamic compression = less efficient
It's a trade-off and difficult to determine which set is more significant - especially given other variables such as vehicle absolute gearing, road grade, environment, etc, etc.
Additionally, when you throw in OEM ECU parameters, everything goes out the window. Dependent on tps/revs/load/iats, etc, the ECU may or may not add or subtract timing and fuel - totally up to the OEM.
So... it may work, and it may not. Completely dependent on application.
The reason for the OP was if an OEM had done as such, I could totally get on board as they have the knowledge and resources to exhaustively test ideas more-so than enthusiasts. Not to discredit enthusiasts or things done outside the real of OEM, just always helps settle a debate easier.
other:
+ decreased warm up time
+ aids high operating (h2o) temps = more efficient
- higher risk of pre-ignition
- reduced output at all times (ever drive in traffic so bad you can't pull out unless you gun it or completely cut-off someone?)
Personally, I'd rather avoid risk of detonation and reduction of power at all times for speculative or modest gains. If anything, some sort of OEM intake to HAI valve is what I'd like to experiment with.
If it works for others, that's awesome! Thanks for the explanations. Always nice to learn new things
