Yeah, I'm familiar with the oil filter study. Here's a final conclusion.
Conclusion
Good construction, good flow, good filtering
In the low-priced group, the AC PF, Purolator PremiumPlus, STP, and SuperTech appear to be good choices. These four filters are "best buys" because they doing most things well and are in the low-priced group.
In the mid-priced group, the Baldwin and WIX appear to be good choices. Both have construction that is excellent.
In the high-priced group, the Amsoil, Mobil 1, Fram XG, and K&N appear to be good choices.
Excellent filtering
The Fram TG and Purolator PureOne have excellent filtering. They do flow less than filters with less filtering. Both are in the mid-priced group. The AC UPF also has excellent filtering, however, the UPF1218 is no longer manufactured. The UPF series does include other filter applications that are still available.
Excellent flow
The Hastings, Donaldson, and Fleetgard all have excellent flow. Not surprisingly, they are also have larger pore sized media. The Purolator PremiumPlus and Amsoil flow less than these filters, but still better than average and have good or very good filtration.
The reader should also consider using an excellent flowing filter and add a by-pass filter such as an Oilguard, Amsoil, or Motor Guard.
Mercruiser Conclusions
The Mercruiser filter is a high-flowing filter with larger pore size. The WIX 51086 does not appear to be a good substitute in this application because it flows less than half as well as the Mercruiser. If one did not mind going to a longer format (the PF1218 style), other excellent candidates would be Hastings, K&N, and Purolator PremiumPlus. All three of these filters flow just as well or better than the Mercruiser, have better filtration, and give the added benefit of more media / increased sump capacity. The Amsoil would have to be another viable candidate since it filters much better than the Mercruiser and it flows almost as well.
Click here for more information regarding Mercruiser applications including additional filters and applications.
Disclaimer and cautions
Since many filter manufacturers contract out their filters, one must be careful that future filters from these vendors are the same as what is presented here. One way to do this is to compare the outside markings of new filters to these pictures.
Just because one filter appears to be a good choice for this application, does not mean that it will be the best for other automotive applications. Other applications involve by-pass valves and other features that may or may not make that same filter the best choice.
Be sure to check your application. There is no guarantee, express or implied, that these filters will work in your application
However, this is only a study of filter media. This is not a comparison of filters themselves as a whole with reguards to flow.