We have many customers that are flying with the Subaru E-81 engine. The EFS-2
Throttle Body Injector (TBI) has been found to have sufficient flow capacity for
the 1800 cc engine up to 5000 RPM. The EFS-2 should also have sufficient
capacity for the 2200 cc engine up to 4000 RPM. The 2200 cc engine running
at higher RPM would require an EFS-3A for proper fuel metering. In most
installations a fuel pump is required for proper fuel delivery. Also, the
engine builder will need to design and fabricate an intake manifold for the
engine.
The automobile or motorcycle carburetors frequently used with these engines
either have no mixture control, or have a crude "add on" the mixture adjusting
device requiring constant mixture control adjustment whenever the throttle
setting is changed. The EFS-2 and EFS-3A incorporate an integral mixture
control, assuring that changes in throttle setting do not significantly affect
fuel air ratio. Both of these TBI's utilize a diaphragm controlled
regulator in place of a float bowl, allowing side draft, up or down draft
orientations.
