Then further down
Here and there
Posts: 61
Joined: February 15th, 2010, 9:49 pm
Re: hiclone
THe idea behind a hiclone is to add turbulence to the flow of air entering the combustion chamber. But it is useless for a number of reasons. Here is some engineering fluid mechanics to show briefly why. It is a simple analysis but is fit for purpose. The reynolds number is a number basicalyl used to quantify the level of turbulence of a flow. So lets assume that the ole 1hz is spinning at 2000 rpm, where maximum torque is generated. Therefore it will be inhaling about 4.2m3/minute, With the kinematic viscosity known, and an approximate inlet pipe diametre of 7cm, the reynolds number is 79500. So what does this mean... well the critical reynolds number for pipe flow is 2300, and fully developed turbulent flow occurs at a RE of 4000. So basically when the air is passing though the intake pipes, its already highly turbulent.
Additionaly, there are further obstructions in the flow; direction changes, orifice plates, filters, etc, that further increase the turbulence. So be assured that the flow entering the combustion chamber is already turbulent.
So a hiclone is clearly nothing but snake oil. And this should be enough proof
is his inlet assumed; too small at 7cm?
then he adds
There are other reasons too. On the hiclone site they use the analogy of an inverted water bottle. This is wrong for several reasons. Firstly, yes the flow if faster if the water bottle has a vortex, but this only lets the air flow in to relieve the back pressure, in a constant manner. If you did this with a funnel. I would think you would see no difference. Secondly. If the hiclone does manage to create this perfect, idealised flow into the engine. As soon as it hits the intake valves, it is ruined.
but most of all, please remember, Toyota and all other engine manufacturers do detailed combustion analyses and computational fluid mechanics to optimise the flow into the combustion chamber and ensure the flame front propogates evenly and fully. If there was a simple way by installing a hiclone, dont you think they would have done it?
Cheers Owen
My comments below.
I do not agree with the funnel comparison, as achieving a vortex flow in a funnel pouring fuel is faster than keeping the funnel full. this questions his technical ability. If a hiclone does speed up the flow in the supply hose but does change or be interfered with further on, there would still be greater airflow than without. Otherwise, is there a blow off valve for it to dissipate? If there is a greater airflow, then there is greater airflow. Later models would be questionable with sensors etc.
and another
Re: hiclone
I wonder how many of the haters on here have tried them?? I myself fitted one to a ba xr6 falcon... Got an extra 50kms to a tank of highway driving... this was not an isolated test but done in outback WA all long distance driving.. definatly improved that vehicle.. don't know about a diesel cruiser...
and one more
Re: hiclone
Picked up some off
eBay for quite a bargain. Fuel economy slightly better. Best improvement for the 1HZ is the improved response to accelerator input (previously would bark and then move) and the one in the snorkel has removed the intake drone.
I'm happy especially given the price I paid.
Even put some in the other vehicles to see how they go.
My final response
people are often refuting something without proper evaluation. Some have questionable abilities to evaluate, but its a little hard to dispute when you do feel the savings. Manufacturers dont do a lot of things, they often cut where they can and who really knows whats happening at valve entry with turbulence? a little hard to get a view really. of course turbulence will change at each change in airflow direction and varied induction locations, but increasing just one areas airflow will have an effect right through but could well be optimized with further ability to carry this on through in whatever engineering feat is possible.
