I have a big dog diablo mp commercial mower with the Kawasaki FX850V engine. The mower is used once or twice a week, but it is run at max capacity for 4-5 hours nonstop each time. I want to get the best protection possible for the engine. I will be using rotella t6 for the oil, but I'm not sure about the filter. The recommended filter is the Kawasaki 49065-7010. I want to know if I should stick with that one or use the fram ultra xg4967 that it cross references to. Also, would a larger xg7317 work for this application? And what is the bypass valve pressure on the ultra, and would that even matter with the synthetic media?

Another topic: would using an oversized filter affect flow rate, oil pressure, or pressure differential across the media? This question is also about using an xg3600 instead of xg3614 on my car.

If the Kawi oem filter crosses to the XG 4967, then the 7317 definitely will NOT work. The 7317 uses metric threads, as opposed to SAE for the 4967. If you want to use a longer filter for the 4967 and access permits then the next equivalent filter application would be the 4386(.75" longer), a common upsize for 4967 applications.

If you're looking to use a top tier filter instead of the Kawi, the FU/XG should fill the bill.

BPV pressure found in link looks to be 14psi.

http://www.fram.com/parts-search/XG4967/?

I think one of the best small engine filters in this size are the Toyota Denso 90915-yzzF2. $34.50 for a case of ten. The center tube is smaller so less oil drains down in a mower like mine where the filter angles base down. I was surprised when I removed the last one, no oil drained out, drains back right away. Not the outer clean oil section, the center tube. Using a larger filter is unnecessary, maybe even harmful, and only makes the engine run without oil pressure longer at each start under the conditions I described.

They have anti drain back valves on them.

The fram does atleast the oem filter may not.

The kawasaki and the fram filter both have silicone adbvs.

Why not just use the Fram XG 3614?
The longer version of that is the XG3600 if there's room.

My 2¢

They have center tubes without anti drain valves on them. The empty center tube has to be refilled and a larger filter means a dry start over a longer time. The Toyota center tube is narrower and therefore fills faster. People using larger filters on mowers with base down filters aren't helping anything. The smaller filter is better. There are filters with center tube anti drain valves but not any of these talked about here.

You have it backwards - outside is “dirty” oil -
Center tube is “clean” oil

The filter is mounted sideways.

How would an oversized filter affect the flow rate, oil pressure, or pressure differential?

A larger filter (of same exact media) would give less delta-p, but would not change the oil flow or oil pressure with a positive displacement oil pump.

Oil flow and pressure is a function of the oil pump volume output, oil viscosity and flow resistance of the engine oiling system. If the PD oil pump is not in pressure relief, then all the oil volume leaving the pump goes through the oiling system, regardless of the delta-p across the filter.