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I tried to find the thread/post but couldn't find it - but I believe, in the context of pros/cons of using a larger filter, one person mentioned that the small or larger choice could have, or probably do have, differences other than size. I think the bypass valve strength was the example or subject... In the past I've used a larger filter, and noticed that, looking inside, comparing to stock size, the insides were different, like the valve thing at the bottom, even though they were the same brand.

In the end, I think I decided that there's probably various considerations that go into the engineer's decision about proper size/type of oil filter, that I don't know anything about it, and that it'd probably be best to stick with what's engineered for the car... The two things that come to mind are the bypass valve thing and oil temp in larger vs. smaller filter. Since our engines spend a lot of time turning off and on (auto-stop), seems like these could matter more than typical. Maybe. Probably not? Who knows, don't know, don't really care.

 

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OK, maybe I don't care, but I am a little curious... I'm remembering that some years of the Insight have an oil cooler, so I'm wondering: larger filter + slightly more oil = cooler oil? I think later model Insights don't have the cooler. Wonder how oil cooler + larger filter compares in terms of oil temp to oil cooler + smaller filter. And perhaps no cooler + either filter...

In general, you'd think the Insight would 'do better' with warmer, thinner oil - since the engine is so efficient, for example, and doesn't heat up very fast, and since with auto-stop it's often shutting off and restarting, in which case maybe warmer thinner oil would pump easier and circulate better... Is the 'bypass filter' the thing that prevents oil from quickly emptying from the filter, or maybe something else? If the Insight generally worked better with thinner, warmer oil, you'd then expect the valve-thing that prevents oil from quickly draining from the filter to be... well, first there, as in some filters don't have those and some do, but also maybe stronger, whatever it'd take to not drain so easily?...

 

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^ That's useful. Looks like there's a few 'technologies' involved, that sound similar but aren't. The thing I was thinking of would be called the "anti-drainback valve." The "bypass valve" or "pressure relief valve" is supposed to allow oil to bypass the filter if it gets clogged...

Here's the bit of text for the "aniti-drainback valve":

"Filters mounted such that oil tends to drain from them usually incorporate an anti-drainback valve to hold oil in the filter after the engine (or other lubrication system) is shut down. This is done to avoid a delay in oil pressure buildup once the system is restarted; without an anti-drainback valve, pressurized oil would have to fill the filter before travelling onward to the engine's working parts. This situation can cause premature wear of moving parts due to initial lack of oil."

The Insight's filter position has the drain end in a slightly upward position. It probably doesn't drain out on its own, definitely not all the oil. Looking at one of the diagrams at the wikipedia article, it shows a valve kind of midway into the filter, I don't think I've seen one of those in the Insight small filter. I believe there is a valve at the bottom of the small OEM-sized filter, which would be the 'bypass filter' thing, not sure about the larger ones.