snorkles

As RA said, your right foot can be your best friend or worst enemy when fuel consumption is mentioned.
Some have said that a forward facing "Ram Head" on the snorkel can help a bit.

Cheers
Pop

hi
i wasnt happy with the turbo and snorkel on my old mazda bravo took the turbo off and had it checked over nothing wrong with it
the turbo boost gauge was slow to rise so i did an experiment and extended the sides and top by 50mm and the bottom edge by 25mm on the ramhead with some stainless steel plate pop rivetting it on (note- i keep my air cleaner very clean so it wasn't that)
what a difference it made the turbo boost comes in earlier and the accelleration between second and 3rd gears is much more responsive because more air is being force in earlier and the indicator hand on the boost gauge rises rapidly now
a very noticable improvement and a worthwhile modification but it hasnt made any difference to economy
cheers

Gday Tim,
Glad yours improved! I owned two of 90series Prado TDs soon after they were released and mine went the other way - might have used 5% more fuel, so I measured the pressures (vacuum) at the air filter and the snorkel (safari) was definitely restrictive compared to the intake inside the LHS guard.

Yeah i cant explain but thats just what happened. I put one on the 150 series, i had only had it for a few weeks but i'm not convinced that it has changed at all.

Gday Pop,
The theory and the practice can be quite different, depending on the vehicle - more factors than what you have mentioned. I've found many 4wds use more fuel when fitted with a snorkel. I think the original poster needs info that's specific to the 4.8L petrol motor.