Wet air filter (part 2)

SCKJCRD · **Posted:** Thu Sep 14, 2006 10:00 pm

A few weeks ago I installed an air filter restriction guage (filterminder). One of the reasons I did it was to see if there really is cause for concern about airbox restriction, especially if the air filter gets wet. Yesterday I finally had an opportunity to put it to the test. We had a plain old rainy day, and after work I went and drove about 40 miles on the interstate in the rain. Between the rain and the water being thrown up by the tractor-trailer trucks I am certain there was plenty of water going into the air intake. I did everything I could think of to (safely) increase the engine's demand for air, for example, running at 75 mph with overdrive off, and accelerating hard up hills. Drove home, stopped the Jeep in my carport, and immediately opened the airbox. There was definitely water in the bottom of the airbox, and the filter itself was damp. But the filterminder indicated no increase in air restriction. None. Now, less suction than it takes to suck soda through a straw will put the filterminder all the way to the red zone, so I can only conclude that a wet air filter is not causing any significant restriction.

If you are interested you can see my filterminder installation here. http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=11545

Jeger · **Posted:** Fri Sep 15, 2006 5:22 am

Are you 100% certain there are no leaks in your setup? The filterminder didnt register any vacuum at all?

SCKJCRD · **Posted:** Fri Sep 15, 2006 7:04 am

I'm comfortable that everything is put back together properly. I also checked the filterminder to be sure it was working. As I said, less suction than it takes to suck soda through a straw will put it all the way to the red zone. I will add that my Jeep only has about 3,000 miles on it, so the filter is still pretty clean. The result might be different if the filter was dirty to begin with.

I don't think I'm the only person who has installed a filterminder. It would be interesting to know what others have experienced.

Jeger · **Posted:** Fri Sep 15, 2006 7:10 am

Yes I am interested as well, maybe the filterminder is not sensitive enough for the CRD. Do you know if the one you got is the same that would be used on a larger engine. I am curious just how much vacuum is pulled I was thinking about hooking up a regular vacuum gauge like you would use to test a gas engine. Maybe that would be a good method to test the variation between a normal clean filter, wet filter, and wet-dirty filter.

Check out all the cool stuff here

SCKJCRD · **Posted:** Fri Sep 15, 2006 8:54 am

The filterminder is very sensitive. It is calibrated in inches of water. A pressure drop of 25 inches of water puts it in the red. Atmospheric pressure and vacuum are typically stated in inches of mercury. One atmosphere is approximately 29.9 inches of mercury. According to a web based conversion program I found here http://www.digitaldutch.com/unitconverter/index.htm 25 inches of water equates to about 1.8 inches of mercury.

spoonplugger1 · **Posted:** Fri Sep 15, 2006 9:09 am

Thanks for the info.

Jeger · **Posted:** Fri Sep 15, 2006 9:50 am

You are right about the sensitvity of the gauge, I didnt know what scale it was in. I run a vacuum furnace and a vacuum melter at work so I deal with things that suck all day :lol:

The fact the gauge didnt show anything at all is what bugs me. I havnt put one on mine yet and I was hoping the CRD would at least move the scale somewhat, at least then I would know the gauge was working.

oldnavy · **Posted:** Fri Sep 15, 2006 10:07 am

Jeger wrote:

You are right about the sensitvity of the gauge, I didnt know what scale it was in. I run a vacuum furnace and a vacuum melter at work so I deal with things that suck all day :lol:

The fact the gauge didnt show anything at all is what bugs me. I havnt put one on mine yet and I was hoping the CRD would at least move the scale somewhat, at least then I would know the gauge was working.

Just make sure you put it on the clean side of the filter. :wink:

I have seen one installed that way before, gage doesn't do much when done that way. :lol:

SCKJCRD · **Posted:** Fri Sep 15, 2006 6:03 pm

Quote:

The fact the gauge didnt show anything at all is what bugs me. I havnt put one on mine yet and I was hoping the CRD would at least move the scale somewhat, at least then I would know the gauge was working.

That surprised me some too. The first mark on the filterminder is at 8 inches of water, so I guess it takes a little vacuum to get it moving. Still, that's only about 0.6 inches of mercury, so it's not much. It doesn't seem as though that little vacuum would be enough to pull oil past the turbocharger seals.

Quote:

Just make sure you put it on the clean side of the filter. I have seen one installed that way before, gage doesn't do much when done that way.

I think I have it on the correct side of the filter. It is plumbed into the airbox cover, which is on the intake side of the filter. It is right next to the factory air pressure sensor. The factory sensor will cause a code if the pressure differential goes above about 10 - 12 inches of mercury AT IDLE. Pretty much useless if you ask me.

longrange2 · **Posted:** Fri Sep 15, 2006 10:12 pm

I drove about 150 miles today in some pretty hard rain between Grand Junction and Denver, CO.. I made a point of stopping near the end of the trip and checking the filter box. There was probably 1/2 a shot glass of water in the bottom of the box but the filter itself was not even damp.

Davesub · **Posted:** Sat Sep 16, 2006 12:10 pm

I also just drove approx 150 miles last night in a rain storm in CT, and NJ and just a very tint bit of water on the bottom of the box and the filter is bone dry.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

what others have experienced.

There is a simple experiment you can perform to be sure the Filterminder setup is working with the CRD airbox.

Remove the circular adapter from the lower airbox

start the engine and let it idle

Take a piece of cardboard that will cover the circular input hole to the airbox, and briefly, and I mean very briefly, less than a full second, block off the airflow. If you keep the blockage to less than a second, it should pull a vacuum within the airbox, but not long enough to cause any problem.

If the Filterminder doesn't show something with that test, it's never going to. Another test is when your filter is ready for a change, take a plant spray bottle, spray the filter with a really good mist, put it the CRD, crank it up and watch the Filterminder.

Hope31 · **Joined:** Tue Aug 08, 2006 2:52 pm **Posts:** 1

I've noticed a lot of diesel owners could use some info on how to use their Filter Minder. The Minder is just a messenger, and is only telling the vacuum level on the clean side of the air filter. Depending on how it was engineered with the air induction system, with a new filter it may show zero, or may be up a notch or two. This is the clean filter restriction level. The typical air filter takes a long time to show any additional restriction from dirt/dust. It may take 50-75,000 miles depending on operating conditions. If you pull a filter and look at it, it will look dirty...........that's it's job !!!! In fact, it filters better than a new filter if it has a dust film. If you don't see the Minder go up, there is no increased restriction. If you change to a different aftermarket filter and see a difference in the Minder reading...........it's just telling you if that filter is more or less restrictive. If it goes all the way to red zone, you may want to think about what type of filter you just installed, as you've just increased the restriction in your air induction system. We've been taught for so many years that we need to constantly change air filters, and that's just not true. Many air filters will last 100,000 miles or more. If you just like changing filters frequently, that's fine, but don't blame the Minder. For more information go to www.filterminder.com

crackercrd · **Posted:** Wed Apr 25, 2007 3:12 pm

My friend has a factory restriction gauge on his 2500 Chevy (gas), the gauge never has shown a restriction in 100K miles. He sucks on it at every oil change to verify it's not broken. I think he changed the filter at 100K just because.

BiodieselJeep.com · **Posted:** Wed Apr 25, 2007 5:48 pm

Thanks for trying this experiment. Appreciate it. I do worry.

midwest · **Joined:** Tue Apr 25, 2006 12:03 am **Posts:** 173

Hope31 wrote:

I've noticed a lot of diesel owners could use some info on how to use their Filter Minder. The Minder is just a messenger, and is only telling the vacuum level on the clean side of the air filter. Depending on how it was engineered with the air induction system, with a new filter it may show zero, or may be up a notch or two. This is the clean filter restriction level. The typical air filter takes a long time to show any additional restriction from dirt/dust. It may take 50-75,000 miles depending on operating conditions. If you pull a filter and look at it, it will look dirty...........that's it's job !!!! In fact, it filters better than a new filter if it has a dust film. If you don't see the Minder go up, there is no increased restriction. If you change to a different aftermarket filter and see a difference in the Minder reading...........it's just telling you if that filter is more or less restrictive. If it goes all the way to red zone, you may want to think about what type of filter you just installed, as you've just increased the restriction in your air induction system. We've been taught for so many years that we need to constantly change air filters, and that's just not true. Many air filters will last 100,000 miles or more. If you just like changing filters frequently, that's fine, but don't blame the Minder. For more information go to www.filterminder.com

I agree! Many people have posted here how the crd "eats" filters. It will foul the filter on the outside fold/edges, and I believe this is a symptom of the dreaded CCV system. However, to say a filter is toast because it has a little dirt/ oil residue on it is a bit much. My owners manual for my 02 Powerstroke says not to change the filter until your gauge is near the "red" zone or you get a warning light on the dash. I don't let them go that far, but I also dont change them out as soon as they show signs of dirt as some here do.

BVCRD · **Posted:** Wed Apr 25, 2007 7:22 pm

I sure do. I change that sucka with the oil every 5K miles. Cheap insurance that I am willing to purchase.

Jeger · **Posted:** Wed Apr 25, 2007 8:10 pm

A little dirt on the filter is no problem, but when the filter material has been so wet it is degrading, you have a problem, or when you go to check your filter and find a whole sheet of paper towel in there stuck to the filter :shock:

Or how about an entire walmart platic bag :!:

That is when I decided to put in the V6 intake, and I havnt had a problem since.

So how about an update on the filterminder, is it working?

oldnavy · **Posted:** Wed Apr 25, 2007 8:36 pm

Jeger wrote:

A little dirt on the filter is no problem, but when the filter material has been so wet it is degrading, you have a problem, or when you go to check your filter and find a whole sheet of paper towel in there stuck to the filter :shock:

Or how about an entire walmart platic bag :!:

That is when I decided to put in the V6 intake, and I havnt had a problem since.

So how about an update on the filterminder, is it working?

You are correct this is probably the most important early on mod of the CRD.

GilaMonster · **Posted:** Wed Apr 25, 2007 9:38 pm

Well, when I saw a water line mark of dirt in my airboxt about five inches from the bottom, and a soggy air filter after one of our great monsoon storms, I changed the airbox out for the snorkel style.
I have not had any water or signs of water in my airbox since, and have been through some other good monsoon storms.

The piece of mind is worth it alone compared to the thought or possibility of hydrolock.

Wet air filter (part 2)

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