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While the logic sounds good, it doesn't hold up in real time pressure testing I've done. The filters involved have very little pressure drop. The CP3 can pull thru 3 filters with NO lift pump involved. It's doubtful the little JK pump would be strained, routing it one way or the other.

The pressure drop between a fresh filter and one that's at end of life is only 2"Hg. It will work either way, before or after. But a FWS filter is most efficient when the fuel is pulled thru it, not pushed (per Baldwin). This is how your stock fuel supply is set up.

When you do add a LP, including an aux filter head for a FWS before the pump, maintains that efficiency, and greatly improves the life of the under hood filter, which is now your secondary filter. One from being downstream of a 10m filter. Two, positive pressure thru the stock filter will utilize more of the full media, with no voids left, which you'll find under vacuum use.

Height location isn't much of a concern. Per JK, what kills the pump is trapped air from not priming properly. It leaves tell tale internal wear marks seen when they open it up for warranty. And he states that if they find those wear marks, any warranty is voided.

Summation; there's no wrong way to mount one, just a better way than others.
A centrifugal lift pump and a gear driven radial piston injection pump are 2 totally different pumps. I have seen Kennedy pumps burn up because people put a FWS filter before it then fill up with a bad tank of fuel which plugged the filter therefore the pump ran dry and died. That is why with Kennedy pumps you put the filters after it. Centrifugal pumps are better at pushing fuel than pulling it. The filter after the Kennedy will still do the same job and ensure long lift pump life.
 

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With a Kennedy pump you want to go after as to not starve and burn up a pump. As the filters start to load up the pump can continue to push through the filters you keep you going.
The issue I see with that is that the FWS works best under suction, before the water is emulsified in the pump.

I see, after reading the entire thread Im not the first to point this out.
 

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The issue I see with that is that the FWS works best under suction, before the water is emulsified in the pump.

I see, after reading the entire thread Im not the first to point this out.
And the water is not getting emulsified when you pump it into the tank or while driving and the fuel is sloshing around in the tank or in the case of Fass/AirDog lift pumps with fuel being returned to the tank or the return line from the engine that dumps fuel back into the tank ? I have been examining my fuel filters since day one and have wasted a stupid amount of time doing this. The first 10,000+ gallons of fuel was with no lift pump and the CP3 pulling through 2 filters. Then 12,000+ with lift pump pushing through the 2 same exact micron/brand filters. The filters have always looked the same and never once have I had water in the second filter. Now I realize 22,000+ gallons of fuel is a small amount but I should have noticed something if one way was clearly better/worse by now.
 

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The issue I see with that is that the FWS works best under suction, before the water is emulsified in the pump.
Suction has nothing to do with it.... it's the "pre pump" location that supposedly has better water separation abilities.

That said... I saw I guy in a Cummins truck pull up the the gas pump, take off his fuel cap.... and you would swear there was someone in the fuel tank , blowing vape smoke out.

A big A/D pump setup was hanging out from under his bed.

If someone stuck a video camera inside a fuel tank with a A/D of Fass set up, I'm sure you would see a big, frothy , Niagra Falls looking mess with all the returned fuel freefalling back into the tank, and if you stuck the same camera in a Kennedy plumbed tank, it would be the exact opposite.

You want clean, calm, low pressure and high volume fuel supplied to the CP 3-4. Thats what the Kennedy does.

If you want hot, frothy, high pressure, muliti time circulated air entrained fuel, buy something else.
 

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Discussion Starter #26
Soooooo....................to get back to my original question. Can the pump be mounted right below the cab at the same level as the top of the tank and pump ok?
 

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After rethinking all of this I think I will run the pump down below by itself and the Racor or Baldwin BF46062 in the stock location.
I thought you answered your own question.

If your going to all the trouble to add a lift pump, I would add filtration too.
 

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That wasn't the original question, but yes...above, below, beside it,...wherever you choose.

What keeps the fuel from bleeding back on a Duramax?
What keeps the cola in the straw with your thumb over the end?
 

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Discussion Starter #29
Thanks guys! The end..........
 

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Aaron, I did a Kennedy pump on my 2500 Saturday and mounted it on a bracket in front of the tank. I *think* it’s for the evap canister on the gassers. It’s out of sight and high enough to avoid getting snagged offroad but sits low in relation to the tank.

But I’m with the other guys if primed properly and no leaks in the system you could mount it on the roof and it would pump just fine :thumb
 

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With a Kennedy pump you want to go after as to not starve and burn up a pump. As the filters start to load up the pump can continue to push through the filters you keep you going.
In a sealed system without air in it, why would it matter which side of the pump you put the restriction on? you will have the same volume of fuel inside the pump in either situation and the same flow rate through the pump.
 

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In a sealed system without air in it, why would it matter which side of the pump you put the restriction on? you will have the same volume of fuel inside the pump in either situation and the same flow rate through the pump.
With the Kennedy unit being a centrifugal type pump running it dry will burn it up quickly. So with this type of pump you want the filters on the outgoing side so the pump always has fuel in it to ensure a long life.
 

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With the Kennedy unit being a centrifugal type pump running it dry will burn it up quickly. So with this type of pump you want the filters on the outgoing side so the pump always has fuel in it to ensure a long life.
I, for one, would prefer to have clean filtered fuel coming into my lift pump to assure a long life. My $30 pump has lasted 9 years so far and filter is between the tank and the pump. Airtex tells you to plumb in this manner.
 

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I, for one, would prefer to have clean filtered fuel coming into my lift pump to assure a long life. My $30 pump has lasted 9 years so far and filter is between the tank and the pump. Airtex tells you to plumb in this manner.
Yes, for your type of pump that would be required. I am exclusively talking about the Kennedy lift pump not all lift pumps.
 

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Magnetically coupled centrifugal pump doesn't require fuel to cool it.

If you've somehow achieved a total clog of a 10-20μm FWS filter from a bad batch of Diesel, you've got other problems downstream.
Not to mention the engine stalling from lack of sufficient fuel volume.

I'll take my chances for better water removal with a pre pump FWS, vs a $100 replacement LP motor....if it were to somehow fail from a clogged filter.
 
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Magnetically coupled centrifugal pump doesn't require fuel to cool it.

If you've somehow achieved a total clog of a 10-20μm FWS filter from a bad batch of Diesel, you've got other problems downstream.
Not to mention the engine stalling from lack of sufficient fuel volume.

I'll take my chances for better water removal with a pre pump FWS, vs a $100 replacement LP motor....if it were to somehow fail from a clogged filter.
Magnetic drive centrifugal pump absolutely require fuel to cool and lubricate them.

Obviously you will have problems downstream but that is not the discussion here.

My Kennedy lift pump has pushed 12,000+ gallons of fuel through 2 filters. My secondary filter has never had 1 drop of water in it because the primary caught it all. I am curious to know how I can improve on a 100% success rate ?
 

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Been running my single Kennedy pump for 10 years on my LB7. No pre filter. Still running strong.
 

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My setup goes like this: stock 36 gal tank > Donaldson P551001 > Kennedy Twins > OE filter head with a Racor PFF50216. The Donaldson is on a Hardin Marine filter head that’s attached to the underside of the bed next to the fuel tank. The Kennedy pumps are on the bracket that came with them and I attached that to the old fuel cooler bracket that GM didn’t use on the 14’s. I also run a filter magnet on the Racor. Overall, it’s simple. Logically it made sense to me to pull fuel through a higher micron filter then push it through a lower micron final filter. Works great.
 
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