OK, I'm not an expert, but the concept of the Hiclone is to swirl the AIR.
Not the air/fuel.
If the air is swirled, then more of it is ingested.
More air, more oxygen, bigger bang.
Sounds good:)
However, us poor folk that run carbies (and this probably applies to injected systems) have a thing called a butterfly. It's a big flap that controls the amount of airflow into the engine.
So the swirl generated by the hiclone is distorted by the butterfly.
Just think of how much pedal you use at 100kmh on the highway. Not much.
So the butterfly is hardly open, so the swirl is destroyed.
WAFTAM
Diesels - well that's a different story:D

