Re: Yamaha EFI vs HPDI
depends on which EFI and which HPDI. basically HPDI injects the fuel into the cyl directly after the ports are covered by the piston at pressures above 600 PSI. EFI injects fuel into the reeds at about 35 PSI, and from there its about like two strokes always were.
some HPDI yamahas use an O@ sensor but not all. all ox66 EFI motors use an O2 sensor.
ox66 uses an altenator driven ign system and HPDI uses a 12v transitor controled (TCI) ign system.
both are decent but I prefer EFI if only given the above choice.
HPDI injects oil into the reeds like yamaha V6 did for years,EFI mixes the fuel and oil in the VST tank and injects the fuel oil mix into the reeds.
in my opinion thats a drawback but they did not consult me on the design.
