OK. Is it marketing or is there a new math on the planet?

NAPA's 3405 (Wix 33405) Fuel filter says it flows 12 GPM.
Sierra's "High Volume" filter says it flows 90-100 GPH.

Now I'm no genius, but doesn't the NAPA filter flow over 6 times more? (12 GPM x 60 minutes in an hour =720 GPH)
I understand that the filter media can restrict the flow, but if anyone can explain this a bit more, I'd appreciate a "schooling" on the matter.

How does one then determine the best separator for a hi-performance application?

Thanks,
Chris

90-100 sounds higher than 12 to me...kinda like mountain grown coffee. Is the rest of the coffee grown in a rice paddy?

I use NAPA

Pressure differential used during testing means everything. So, doesn't the line size, length, height over the pick up , and etc.

Have you ever seen fuel pump 'dyno' chart ? Pressure and voltage (if electric) mean everything. Do they tell you this ? Not many do...a few dop.

Anyway, 60psi of fuel psi going thru the same seperator is going to flow a schitton (yes that's a measurement up here) different than at a - psi (seperator mounted before a mech pump) .

Advertising without using the same test standards...and if that part is actually tested at or guessed at for it's performance.

I cant answer your question. But, I can tell you, I run the wix 33405 filters, and they supply enough fuel to my supercharged 800hp carb engines.

Found one company that lets on to what I said ABOVE:

i also use that wix filter.i can tell you that at wot i maintain 7.5 lbs of pressure at 1200 hp.dam good filter!

Does the Wix interchangeable with the standard Merc filter?

Thanks,

Padraig

Wix crosses over to Merc. Do not use fram fuel water sep filters and believe it or not Mercs are not that good either. No BS - I have cut open over a 1000 fuel filters from brand new to used to very over used, (the same tool that cuts opens oil filters is the tool to use).

Merc has a rubber pad thats glued internally in the bottom of the filter that keeps the spring in place against the end cap of the filter. This glue and pad over time turns into goo and runs thru your fuel system. FYI - I have posted this info before.

Believe it or not Sierra is not a bad filter It can be bought in 3 different sizes including extra large and can be bought in a 21 Micron rating and a 10 Micron rating of your choice - their filter media is larger than wix and Merc plus the long gone Mallory Marine in which was made by wix. The negative side is bigger filter media less water carrying capacity. IMO if you have that much water in your fuel you have more problems that filter capacity.

Racor is very good fuel water sep filter plus has a drain screw on the bottom for checking for water and condition of the fuel, wix is good, Baldwin is good, also Yamaha is good to and will fit many Mercruiser apps plus Yamaha has an extra large filters to. I think Sierra has something to do with Yamaha fuel water sep filters but I could be wrong. Also FST is good to. I am looking at possible selling those to as I already sell all the rest..

I bought an FST.
Nice piece but not the cheapest.