Microns, whats smaller?

Big Bore · Jun 23, 2011

Ok I'm going to post this down here and hope no one upstairs sees it. LOL

Buying replacement filters for my AD and they sell 2 and 10 micron filters. Since it's pre-pump, and I am deleting the stock filter housing and doing a remote post pump spin on, I don't see the need for a super fine pre-pump filter.

Problem is, for some reason I cant determine which is smaller, higher numerically or lower on the microns. I'm thinking lower numerically but want to be sure so I can place an order.

Thanks guys.

Dzchey21 · Jun 23, 2011

2 micron is smaller... way smaller 10 od usually primary 2 is secondary for fuel

sgleshot · Jun 23, 2011

I run a 10 micron absolute post pump currently in my regulated return setup, its better than stock, but id like to go a little finer with it. Im running a 12 micron nominal water seperator for the pre-pump filter. Had the same setup on 2 different superduty's, works great.

rsr911 · Jun 24, 2011

For reference 25.4 microns equals 0.001"

More reference? Typical main bearing tolerance in an engine 0.001-0.003" with the loose side being favored in a drag race application. Your oil filter is about 25 microns.

On my IDI I have to filter to 5 micron absolute or better to prevent onboard filter clogging. I have seen evidence to suggest that the PSD onboard filters are more coarse than the IDI filters.

A human hair is approximately 25-50 microns in diameter.

Thickness of the ink printing on most flexographically printed labels, less than 2.5 microns or less than 0.0001"

One layer of evenly applied paint is 0.001-0.002" thick.

rsr911 · Jun 24, 2011

http://www.ilasseurope.org/ICLASS/ilass2002/papers/066.pdf

This study suggests the orifice diameter for a diesel injector is between 0.100mm and 0.227mm or 100-227 microns.

389sixpack · Jun 24, 2011

rsr911 said:
For reference 25.4 microns equals 0.001"

More reference? Typical main bearing tolerance in an engine 0.001-0.003" with the loose side being favored in a drag race application. Your oil filter is about 25 microns.

On my IDI I have to filter to 5 micron absolute or better to prevent onboard filter clogging. I have seen evidence to suggest that the PSD onboard filters are more coarse than the IDI filters.

A human hair is approximately 25-50 microns in diameter.

Thickness of the ink printing on most flexographically printed labels, less than 2.5 microns or less than 0.0001"

One layer of evenly applied paint is 0.001-0.002" thick.

That is not correct.

1 micron = 10^-6 m = 0.000001 m
10 micron = 10*10^-6 m = 0.00001 m

1 µm = 3.937007e-05 = 0.00003937" or approx 4 hundred thousandths of an inch.

and a 10 µm will pass particles smaller than 0.0004" 4 ten thousandths of and inch.

rsr911 · Jun 24, 2011

My source among others is www.onlineconversion.com. I have seen what appears to be a metric micron definition such as u mention as well as my definition. My definition is a micron is essentially one thousandth of a millimeter. Btw if u multiply .00004 x 25.4 you get about 0.001" which is what I said. If u do .00003937 x 25.4 you get exactly 0.001". So what was I wrong about.

Mdub707 · Jun 29, 2011

More importantly, you need to be looking at these filters if they are nominal or absolute.

rsr911 · Jun 30, 2011

I recirculate through 1 micron nominal filters and pump into storage and the truck through 3-5 micron absolute depending on what brand I'm using.

BnjmnAlan · Jul 2, 2011

rsr911 said:
I recirculate through 1 micron nominal filters and pump into storage and the truck through 3-5 micron absolute depending on what brand I'm using.

What kind of 1 micron nominal filters are you using? Are they the string wound ones from Mcmaster?