charl makssi replied:

hi paul,
i have hi clone fitted to my 4.2 94 patrol petrol. in all fairness paul in the 12 months and perhaps 20K later i have to say the benefits are negligible. may be different for diesel but i think the principle should be the same will see what others say on the forum hope from diesel point of view.

Bill Church replied:

Paul, I have a '99 TD5 Discovery. I have a Hiclon before the turbo, and it brings the turbo onto boost about 500 rpm earlier. I have found a slight increase in economy, but love the extra jump off the line that the Hiclone gives.

Andrew replied:

Paul, do a search on "hiclone" in this forum, you will find some interesting discussions,
I still would love to know the magic of how putting a teensy bit of finned steel in an induction inlet before the turbo is going to induce a swirl effect that is not going to be affected by the turbo...
engine designers spend millions on getting many technical aspects right, including swirl of fuel/air mix within the combustion chamber for peak efficiency and power, that are specific to THAT engine, ...so, really, this so called hiclone..metal magic, it is so generic, yet people claim it to respond to THEIR vehicle's design..and then the simplton's say if 1 is good, 2 must be better.. theoretically, it is actually a restricter, in an induction inlet that needs as least restrictions as is possible for effiency.
The swirl that occurs when the air enters the combustion chamber is caused by piston head and combustion chamber design, as designed by the manufacturer, not by some piece of junk stuck 2 foot down the induction inlet before the turbo, and purchased from Lou Knee's Auto Wankmart.

John Sullivan replied:

Paul, I had the recommended two fitted, dynoed before and after fitting. Extra 2 kw, tried for a month no change in fuel economy. Removed them under money back guarantee, spent the money on a turbo boost controller and 3" mandrel bent exhaust, big difference in power and lowered rpm of boost coming in from 2200 to 1600. If I drive slower I can save fuel, but I use the extra power and fuel economy is the same. Hope this helps.

John Sullivan replied:

Sorry forgot to say I have a 96 Nissan 2.8 TD