Oversized Insulated Oil Filter

[twj347]

The stock filter on my car is rather small looking, so I picked up some oversized filters. I went with a Baldwin filter (B161-S) since they're the only filter manufacturer that matches Subaru's 23psi bypass valve setting. It has about 50% more volume than the stock filter. The advantage of an oversized filter is that it has more filter media so it will last longer, and it won't go into bypass as easily when the oil is cold, resulting in more filtering.

I guess my only concern is that if the bypass valve doesn't function well, it will take longer for the oil filter to fill up on engine start, leading to more startup wear.

I'm planning on insulating the oil filter with insulating tape to keep more heat in the oil between starts, as sort of a poor-man's Prius insulating coolant thermos. My car has an oil-to-coolant heat exchanger, so it should benefit coolant temps as well, and I'm not concerned about higher oil temperatures. I'm not expecting it to make a stellar difference, but it should at least help.

Has anybody done this sort of thing before?

[ThermionicScott]

I've heard of large-volume oil filters that have the same filter media, just in a bigger can. It would be good (for science!) to cut them open and find out one way or the other.

I used to run a large (Mobil M1-104) oil filter in my Subaru, but switched back to the M1-108 when I read that increasing the oil capacity also means slightly slower oil warmup. At 237,000 miles, it's looking like the body will disintegrate from rust before the engine wears out, so bypass valve behavior at startup isn't on my radar anymore.

Insulating the oil filter is a neat idea -- not having the oil filter out in the breeze ought to help things out. Have you insulated your oil pan yet?

[twj347]

I've seen some videos of Baldwin filters cut open. They seem to be quality filters and always take up the whole can.

I wanted to insulate my oil pan, but only a very small portion of it is accessible from underneath the vehicle. After installing an oil pan heater, very little of the oil pan is available to insulate. At least the OEM design keeps most of the oil pan out of the wind.

As far as oil volume, I'll probably just continue to dump in a 5L jug after installing the larger filter, even if it means the oil level being a quarter liter below the full line.

[oil pan 4]

It's not always the same filter media.
I found this out when going from a PH8 size to the larger size. The 97% single pass went from something like 5 micron on the smaller filter to 30 micron on the larger one.
So you better make sure.

[twj347]

Originally Posted by oil pan 4

It's not always the same filter media.
I found this out when going from a PH8 size to the larger size. The 97% single pass went from something like 5 micron on the smaller filter to 30 micron on the larger one.
So you better make sure.

I checked with Baldwin, and the efficiency rating is 18 micron (50% efficiency at 18 micron, 98.7% efficiency at 40 micron). These numbers don't seem to be stellar, but I'll try to find the rating of the stock filter.

The area of the media is 42% higher than the stock filter.