Larger Quality Oil Filter for 2.5

[lmdew]

Anyone found a larger Quality Oil Filter for the 2.5. The OEM filter is so limited on filter material area.

[Guest lothar34]

How big a filter did you want?

[sprintman]

Bigger than the piddly OEM one. It's a joke!!

[ibis315]

I've read somewhere that H6-3.0 oil filer fits into the H4-2.5 engine. It's a larger capacity filter, but the threading and the diameter is same as the 2.5 engine.

[sprintman]

Tks i'll look into it...s

[LameRandomName]

Make sure that whatever filter you choose it has at least as many little holes around the perimeter of the mounting surface as the stock one does.

[Commuter]

The filters for the H4 and H6 engines are virtually identical. The only significant difference is in the backplate. The H4's backplate is dished outward slightly. The H6 is dished inward. Be careful putting the H6 filter on the H4, the threads "may" not catch sufficiently. I'd be surprised if there is any difference in the filter media itself between these filters, but I don't know that for a fact.

 

Physical size is only one indication of the filtering capability of the filter media. I've cut open a few brands of filters in the past couple of years. You really want to know the filter media area. Beyond that, you really want to know the capability of the filter media. (Single and multi-pass effieciencies at different micron sizes, pressure drop for a given flow, dirt loading capacity...) It's nearly impossible to find out this sort of data.

 

The Subaru OEM filter is made by Purolator. When I cut one open, it had fewer pleats than the Purolator PureONE filter. (I don't know how it compares to the Premium filter.) FWIW, the "other" Subaru OEM filter in Canada is made by Fram and it had even fewer pleats still. ALL these filters are (practically) the same exterior size.

 

If you want a better filter, try the Purolator PureONE. It has some synthetic fibers that allow it to filter to smaller micron levels. It has a fairly generous filter media area. I have no clue about flow, as I've never seen any data on that. It's a bit pricey, but if you buy 6 or 12, you should be able to get a pretty good deal.

 

Beyond that, there are other filters that will fit. You just need the right thread and gasket diameter. Some people have gone this route. Now whether other "specs" are ok, I cant tell you. (Eg, does the bypass valve open at the prescribed pressure... )

 

And beyond that, you can look at premium filters, or bypass filter systems, permanent washable filters, etc. Go nuts.

 

Commuter

[Guest lothar34]

I've cut open a few brands of filters in the past couple of years. You really want to know the filter media area. Beyond that, you really want to know the capability of the filter media.

 

Have you cut open any Mobil 1 filters? That's what I've been using.

[sprintman]

Good post commuter. There are filter flow/pressure drop figures available on BITOG forum. I use PureONE on my other vehicle (Mazda turbo) but I don't think it's a great flowing filter. Can't get Mobil 1 filters here but thats what I'd use if I could. K&N have a good oil filter, can't say the same about their air filter. Users always have high Si numbers (dirt) in oil analysis.