Pre Cleaner Decision Making

[scubasteve2002]

I have been doing a lot of research on pre cleaners for my 2008 Jeep JKU. I wanted to write this to clear up any confusion when it came to the cyclonic self cleaning style cleaners (Sy-klone 9000 series, Donaldson Top Spin, etc.). I was having an issue understanding why there was a range for min-max cfm. I was also searching for a great deal and found the Donaldson Top Spin. It is cheaper by $30 compared to the Sy-klone. I did some research and found the Top Spin has a cfm range from 200-450 where the Sy-klone has a range of 100-275. In my head I'm thinking the Top Spin would be better for my application.

Fast forward through some calculations at max rpm on my Jeep I'm running about 268 cfm and at idle only 70 cfm. I also calculated what my rpm would need to be to get the lowest cfm on the sy-klone (100cfm). It came to be 1864 rpm. Which to me seems like a decent slow speed in a convoy on a difficult road. (I will do a test tomorrow on my way to work and see what a 20mph, 30mph, 40mph, 50mph, and 60mph rpm is.)

So through all this calculation I concluded that the Top Spin will not be the best option because the internal propellor would not be moving at low speed and would take 3,727rpm to even get the propellers to the minimum cfm. With no propeller movement means no pre cleaning. So make sure when you are deciding on a pre cleaner that is self cleaning do your calculations and figure out which units work better. Hope this helps out!

 

[Tim]

I have been doing a lot of research on pre cleaners for my 2008 Jeep JKU. I wanted to write this to clear up any confusion when it came to the cyclonic self cleaning style cleaners (Sy-klone 9000 series, Donaldson Top Spin, etc.). I was having an issue understanding why there was a range for min-max cfm. I was also searching for a great deal and found the Donaldson Top Spin. It is cheaper by $30 compared to the Sy-klone. I did some research and found the Top Spin has a cfm range from 200-450 where the Sy-klone has a range of 100-275. In my head I'm thinking the Top Spin would be better for my application.

Fast forward through some calculations at max rpm on my Jeep I'm running about 268 cfm and at idle only 70 cfm. I also calculated what my rpm would need to be to get the lowest cfm on the sy-klone (100cfm). It came to be 1864 rpm. Which to me seems like a decent slow speed in a convoy on a difficult road. (I will do a test tomorrow on my way to work and see what a 20mph, 30mph, 40mph, 50mph, and 60mph rpm is.)

So through all this calculation I concluded that the Top Spin will not be the best option because the internal propellor would not be moving at low speed and would take 3,727rpm to even get the propellers to the minimum cfm. With no propeller movement means no pre cleaning. So make sure when you are deciding on a pre cleaner that is self cleaning do your calculations and figure out which units work better. Hope this helps out!

I also went through some similar calculations for my normally aspirated 4.2L diesel. Then I found the decision was further complicated by trying to find something to match the top of the safari snorkel. As a rough rule of thumb I was told if the cyclonic filter was over 7" in diameter there wasn't going to be enough flow/spin to throw the dust to the outer edges where it's trapped. Also if you are worried about performance only run the cyclonic filter off-road and use a standard ram head on road.
In the end the one I bought was one that fitted the snorkel head. It's a bit bigger than I wanted but it does work and you can see dust/sand collecting at the edges. Some still gets through into the airbox but I guess that may always be the case?


Sent from my iPhone using OB Talk