Engine Intake Air Filter Lesson Learned

[OLLIE]

Several months ago I was visiting Larry (Cruiserlarry) at Dirty Parts and I asked him what kind of air filter he ran in his FJ. I have been running one of the K&N filters that I take out and clean and treat with oil after any dusty trip I might take. Larry told me that he runs an oil-less air filter made by AFE that only needs to be knocked clean and can be cleaned with a mild detergent and water mix if it is really bad. I thought that that made a lot of sense if you were on a long trip or expedition. You would be required to carry the cleaning kit with you. I had to take some stuff to Larry last week day at his shop and decided to pick up one of the AFE filters. I changed it right there in has parking lot. Ihad just cleaned my K&N filter a week prior to that. I felt a noticeable difference in performance immediately.

As many of you know that has caravaned with me, or ridden with me, my FJ hassn't been getting good gas mileage at all. With all the stuff I have on it and in it the gross weight is rather high. I always thought that was the reason why the gas mileage was so poor. However, I haven't added anything of significance to my rig lately and my MPG seemed to be gradually getting worse. I was lucky to get 180 to 190 miles to a tank of gas during highway driving. In town and to and from work there were times when it would be less than that. On the tank of gas I put in it after changing out the air filter I got 220 miles to that tank. I haven't seen that kind of mileage in nearly 25K miles.

So some food for thought on this subject is that just because you have one of the cleanable air filters that claims a life of a million miles don't depend on that. Eventually that oil treatment degrades that filter. If you have been running an oil type air filter for an extended period of time you might want to see what kind of shape it's in.

[photojeeper]

Thanks Ollie, I cannot use the K&N in my 98 Tacoma due to the air mass sensor being to close to the filter. The oil got on it and was making more smog, almost failed a smog test. Going to get the dry one for the Tacoma. Might look into getting one for the Jeep, I use the K&N kit, looks like it might be the same filer size as the K&N but only dry with the pre filer. I will check into that.

BTW here is a Google search for the products and the URL for their home site.

Home Site: http://afepower.com/

Google Search: http://www.google.com/search?hl=en&sour ... f&oq=&aqi=

JJ

[cruiserlarry]

At Dirty Parts, we have been selling and using the AFE (Advanced Flow Engineering) Pro-Dry filters in OEM replacement and intake systems since they first came out...

While and oil-type air filter works well, over time the dirt/oil mixture can get packed into the fiber filtering medium. Even with a thorough cleaning, it may become difficult to restore the filter's original performance. This is especially true when you off-road or tranverse dusty areas frequently. So, even a "Million Mile" filter's performance degrades significantly over time.

The AFE Pro-Dry filter has a slightly reduced flow compared to an oil-impregnated air filter, as the filtering medium is slightly denser. But the convenience of being able to clean it on the trail to 80%+ of new by just slapping it, without leaving chemical residue or making a mess, is priceless. Vacuuming it is even better, or you can wash it with water and mild detergent to restore it to virtually new condition.

AFE Pro-Dry filters are available for most vehicles, and as replacements for AFE cold air intake filters, too. Dirty Parts also sells the AFE CAI with Pro Dry filter in them.

[DaveK]

Tech question:

If the AFE filter exhibits a slightly reduced air flow, then Ollie's perceived performance gains must not have been due to the new filter. I suppose a possible explanation might be a very clogged oiled filter???

[cruiserlarry]

Tech question:

If the AFE filter exhibits a slightly reduced air flow, then Ollie's perceived performance gains must not have been due to the new filter. I suppose a possible explanation might be a very clogged oiled filter???

Well, that's what we were saying - the oil-type filters get "clogged" after long term consistent dirty environment use, to the point they cannot be restored to their original flow after cleaning. The different in flow is minimal in cfm; and that difference is comparing both filter mediums when new. Once the oil-type filter is in use, it's ability to restore to new condition diminishes faster than a Pro-Dry filter.

So if Ollie had installed a new K&N, he would have probably seem the same improvements, but the Pro-Dry will stay consistant over a much longer time if used off-road regularly...

Hope that helps

[DaveK]

So..............what you're saying is that Ollie hadn't cleaned his air filter very well.

Tsk, tsk tsk.

[OLLIE]

So..............what you're saying is that Ollie hadn't cleaned his air filter very well.

Tsk, tsk tsk.

No.... What he is saying is that the oil filter, even when cleaned well and regularly, loses its cfm efficiency quicker than than a dry filter. The dry filter doesn't have a residue on it that holds dirt like the oil filters do. Over time, even when cleaned regularly, the oil filter wasn't letting go of all the dirt/bebris. So although it was filtering better it was starving my engine of air and getting worse.

Is that better said and clearer????

[traveltoad]

And the advantage over a standard paper filter is... being able to clean it vs getting a new one? How do the AFE filters flow compared to a stock paper filer?

[cruiserlarry]

The AFE Pro-Dry filter is far superior, both in flow and ability to hold dirt, than an OE style paper filter. The fiber material doesn't break down if it gets wet, either, so water has a much harder time passing through the sturdier material.

To help understand the difference, you need to realize that a K&N (and any oil-type air filter) uses a larger pore thinner fiber material than a dry fiber filter. The oil is applied to the fiber to suspend particulates off of the fiber, allowing the air to pass through the larger pores while using the oil to trap the dirt, which is suspended above the fiber itself. Unfortunately, with more intense use, the oil/dirt mixture eventually get impregnated into the fiber itself, and is very difficult (impossible) to completely clean out. If serviced often enough, or driven in mild conditions, the dirt/mixture is easier to wash off, and the fiber remains "clean". So, for normal conditions, the oil-type filter has slightly larger pores, and allows more air through than the Pro Dry filter.

The Pro-Dry fiber, with tighter pores and thicker material, does not require oil to prevent the dirt from passing through. The dirt remains relatively dry, and easier to vacuum/wash off thoroughly, even under harsher operating conditions. The dry fiber material is far superior in strength and consistency than the OE paper filter. The OE has the smallest pore size, as paper material has far less rigidity than the fiber, so the denser paper OE filters use helps to prevent collapse and complete restriction.

In summary, both Pro Dry and oil-type "permanent" filters are superior to stock paper. The oil type has slightly more flow, but requires more frequent service intervals, and loses efficiency faster under harsher conditions. The Pro-Dry has a very slight efficiency penalty compared to the oil-type, way better flow than OEM, and is easier to service in the field with better long-term results.

Hope that helps, cause I'm getting a Carpal-Tunnel relapse...

[OLLIE]

And the advantage over a standard paper filter is... being able to clean it vs getting a new one? How do the AFE filters flow compared to a stock paper filer?

From my experience the difference is quite noticeable. Also the cost of replacing the stock filter all the time as opposed to cleaning a filter adds up too. At nearly $20.00 per filter (OEM) I would have hundreds of dollars into air filters alone with the current life of my truck. The air filter was the first mod I do to any of my vehicles. My wife's 4-Runner has the washable filter in it too. I probably will never need to replace that one because it obviously doesn't see near the dirt and abuse of my FJC.