>>16726409>or the most simple of them all is put restriction on intake so the intake is always starved thus less air.Yes, this is what restriction is, but on an intake setup that does not automatically adjust the AFR to accommodate for this, you have to also manually set the fuel intake volume to the proportional restriction of the air. On a fuel injected engine you have to tune the ECU to ignore performance and purposefully retard the air and fuel at the proportional ratio. Restriction alone will result in loss of engine power, but it can be tuned just right so that you have the minimum amount of power needed to run the gearbox effectively and normally.
This is basically proportional restriction in this video. Stock this engine should get about 15 mpg highway, he gets 41mpg and drives it for over 1,500 miles at highway speeds without issue.
https://youtu.be/1xHQWu2ZzPc
To show you the effect of restriction here's the rough stats on his setup.
1974 Ford 5.0l v8
~310 hp
~330 ft lb torque
390 CFM stock 4 bbl carb
Restriction
~59 hp
~140 ft lb torque (intsantly)
>150 CFM lawn mower carbAFR is the same on both setups,14.5:1.
The smaller air and fuel volume and diameters of the smaller carb starves the engine at higher RPMs resulting in power loss but massive gains in fuel efficiency. It is setup in a way that it does not stall. Other variables are also happening but this is the gist of it.
cont.