Fuel/Water Filter 30GPH vs 60GPH

Those flow rates are nominal i.e. when the filters are new. A 60 gph filter can hold a lot more dirt before you see a degradation in flow that will affect the performance of your engine.

Most large engines use 60 gph filters.
 
DennisG01 said:
With a single 250 OX66, I assume a 30GPH is enough? If both filters are rated at 10 micron, what are the pros/cons to using a 60GPH?
Click to expand...
The flow rate specified for a filter is the actual capacity of the filter. To determine the actual flow rate of the entire fuel delivery system a lot of factors come into play: Number and type of fittings, type, size and length of lines, bends etc.
Of course the flow can't be more than the lowest component.
Regardless as long as the theoretical flow to the motor is less than the actual demand, all is OK.
So will a 60 GPH perform better than a 30gph filter? Not if a higher flow is not needed or there are other flow limiting components in the fuel system.
I agree with Doc Stressors comments with the caveat that although the maxium flow rate will decrease as the filter gets clogged from contaminants, that won't affect performance until the decreased rate is less than the actual need.
 
DennisG01 said:
With a single 250 OX66, I assume a 30GPH is enough? If both filters are rated at 10 micron, what are the pros/cons to using a 60GPH?
Click to expand...

As doc says, most bigger outboards (like yours) use a 60gph filter. There's obviously a reason for that (margin of safety ?) so Im wondering why you would consider a 30gph filter. There aren't any "pro's" to that as far as I can see. I believe my f-250 burns 22gph at wot so, a 30gph filter with the bends, fittings and dirt accumulation mentioned before, may be getting dangerously close to its limit at some point before its changed out. Maybe I'm taking a simplistic view but frankly I can't see any purpose of downsizing to a 30gph filter on a 250. Of course it wouldn't be the first time that I was missing something.
 
I had thought (possibly mistaken) that the max GPH for the engine was somewhere in the low 20's, which is why I thought the 30GPH was sufficient - I didn't realize that a 60GPH was normal practice. I do understand what you're saying about "losses in flow due to bends, fittings, etc". Good - thanks for the clarification, guys.
 
DennisG01 said:
I had thought (possibly mistaken) that the max GPH for the engine was somewhere in the low 20's, which is why I thought the 30GPH was sufficient - I didn't realize that a 60GPH was normal practice. I do understand what you're saying about "losses in flow due to bends, fittings, etc". Good - thanks for the clarification, guys.
Click to expand...

Dennis..you're not mistaken about the GPH on your engine; I assume its about the same as mine (22gph at wot). The point , I think , is that you have a greater margin of safety with the 60 gph filter than you do with the 30 gph filter. Consider at some point you get some dirt or water in your gas and your engine takes a drink. You have more time to (hopefully) change the filter before it gets to the engine. The other thing is that I would be tempted to change the 30 gph filter more often for that reason, so I don't think I'd be saving any money .
 
When we had the single 250HP OX66 on our Islander we could hit 28+GPH at WOT, accurately measured by a FloScan 9000 series. So we used a 60GPH fuel/water separator element.

When we repowered to the twin F150s, we switched to twin fuel/water separators and use 30GPH elements in those.

Reserve capacity in both cases.

I would stick with the 60GPH for the OPs single 250HP OX66.

JMHO,
Brian
 
Are these numbers for flow a direct reference to the Yami tall and short water separator? The short or mini is recommended for motors 115hp and under, above use the tall filter. This info comes from the filter guide.
 
You must log in or register to reply here.