Diesel filter before or after lift pump?

[great white]

I'm getting ready to buy a racor (haven't decided which yet) to prefilter the fuel in my 98.

The question is, should it be installed before or after the lift pump?

IE: should the LP push through the media, or should it pull?

Or does it make any difference at all?

I'm still trying to decide which one, but it will at least have a water separator and I'd like it to have a fuel heater.

On the subject of fuel heaters:

I've seen both electric and recirculating. Any opinions as to which is better?

Electric seems to be the easier install, but recirculation (warm return fuel from the engine to tank) seems to be a simpler (less trouble prone) system....

 

[Burning oil]

I would pull the sock then install filter pre LP.

 

[Missy Good Wench]

I have a Racor 230R2 filter after the pump and just before the IP.
The lift pump is not meant to suck through filter media.

I fine Screen or "Clod sifter" is fine but, the small micron media needs to be Post lift pump..

I use a 2 micron filter in my Racor.
Needs changing a little more often but it really gets the crap out of the fuel for sure.


Missy

 

[Matt Bachand]

I have a walbro pushing into a Racor then another Walbro after the Racor before the FLT MGR. This gets me 10psi at the IP. I love it.

I have the pre-Racor walbro on a toggle switch, but it gets left on mostly.

 

[Burning oil]

To me The main reason to install a filter is to get rid of that PITA sock. The stock FM will do the rest. You wouldint want to use a 2 micron pre LP, but something like a 20 micron would be good. Something to catch the cigerette butts and june bugs.
Im doing the same job tomorrow on the 94.

 

[Matt Bachand]

To me The main reason to install a filter is to get rid of that PIA sock. The stock FM will do the rest. You wouldint want to use a 2 micron pre LP, but something like a 20 micron would be good. Something to catch the cigerette butts and june bugs.
Im doing the same job tomorrow on the 94.

The clear water bowl on a racor is great. Not only does it trap crud, water, and anything heavier than diesel, but it gives you a visual of your fuel at a glance. I'm running a 10micron Racor ATM, and the filter is huge, and cheaper than the FLT MGR's, so its much more cost efficient for filter life cost too.

 

[Acesneights1]

I used a Holley inline glass fuel filter pre lift on my Burb because I couldn't use the Sock with my aftermarket PU and I still have my FFM post LP. I have to figure out something better before the winter because that might be a freezing point as TD pointed out. Alot of the Hi perf LP's like Raptor/Air Dog/Fass use an aftermarket larger PU tube with no screen so really I don't think you need the screen so much anyway. I mean how many people have put compressed air through thier and blew it off when it got clogged. Pre LP filter or screens primary purpose is to protect the LP from crap. The FFM protects the engine/IP.

 

[Turbine Doc]

I went pre lift, as the pumping elements are damaged by the crud in the tank, use a coarse filter 30 micron so pumping is not compromised, this pre fillter is meant to "sift" the larger stuff so the finer media of the on engine filter is not overwhelmed by total solids in the fuel.

A pre filter protects your fuel delivery system, the on engine filter protects the engine/IP/injectors.

Best system would be the sock, into a 30,then the lift, to a 10, to a 2 micron just prior to the IP.

Folks that put a 2 micron on as a primary prior to the lift pump are getting clean fuel but are putting undue restrictions to delivery in total.

 

[Turbine Doc]

I

Best system would be the sock, into a 30,then the lift, to a 10, to a 2 micron just prior to the IP.
.

That said how much available real estate for the perfect system becomes a consideration so I compromised. Starting in the tank with the sock, a 30, into the lift, and out into the 5 micron nominal OEM in the filter mgr (FTB modified) out the fm and into the injection pump.

 

[great white]

Hmm, sounds like pre-lift pump is in the lead with the locals...

 

[buddy]

I would do like Matt did, and have one LP on each side of the filter .

I have my 12micron filter pre-LP, although I have an extra Walbro so will eventually do like Matt and install it inline between the tank and filter.

 

[great white]

So, any comments of the fuel heater?

Electric or fuel return heated?

Mainly for the colder climates, northern states and Canada....useful or a waste?

Keep in mind, I could be dealing with -30 to -40 Celsius temps on a couple months notice at any time, depending on where the military moves me....

 

[Matt Bachand]

I would do like Matt did, and have one LP on each side of the filter .

I have my 12micron filter pre-LP, although I have an extra Walbro so will eventually do like Matt and install it inline between the tank and filter.

Do it soon Buddy, It most definately gives MORE fuel to the engine with the same pedal position when I switch my my other walbro on.

I left the built in walbro screen in the pre-Racor walbro, and removed it in the post Walbro Pump.

Having it switchable lets you feel the difference months down the road when otherwise you would have just accepted it as norm. Also prevents possible over-pressurizing.

What I usually do is leave it off, until fuel demand is enough to drop PSI below 4-5 then I switch it on and it brings it to about 8 on the highway.

Fuel pressure never remains constant for whatever reason. Sometimes its at 10, sometimes its at 7 with both pumps. Sometimes its at 5 with one, and sometimes its at 3-4.

Seems ambients don't matter much, not sure if a 'warmed up' pump puts out more or less psi, or if the variation is in my fuel pressure gauge.

 

[Burning oil]

So, any comments of the fuel heater?

Electric or fuel return heated?

Mainly for the colder climates, northern states and Canada....useful or a waste?

Keep in mind, I could be dealing with -30 to -40 Celsius temps on a couple months notice at any time, depending on where the military moves me....

I dont know what temps like that even mean, except thats just way to cold. I can relate alittle to cold fuel though. I run WVO and it gets cold enough here to make it almost a solid (very thick). So, if I were to heat the filter then thats fine, but the line from the tank to the filter and filter forward is still very thick. Seems you would have to heat the rest of the system also.
On my WVO system its heated from the PU until right before the IP.
Anyway not to get off on to a WVO topic. Not sure if you would have the same issues with diesel as WVO.

 

[Missy Good Wench]

My rig has the 2 mic Racor mounted to a custom bracket up by the ABS unit.

The filter sits between the Alternator (95 truck) and the ABS unit.

The only reason I installed it and removed the factory unit was that the factory one rotted out in the bottom and started leaking.

This setup got rid of the fuel lines under the intake.

Seems to provide plenty of fuel.
Its rated at 40 gallons an hour flow though the media..

These systems (6.5 electronic) flow a lot of fuel through the system and back to the tank.


Installing a "clod sifter" before the filter is certainly not a bad idea.

The tank sock gizzmo is a PITA it it gets full of crap. Not to mention the work involved to get the tank out of the truck.

Missy

 

[ak diesel driver]

the oem fuel heater works just fine. I would stick with it and do a clod sifter pre lift

 

[Matt Bachand]

Thats another bonus of the clear racor bowl, you can see the fuel and drain a little bit to make sure its not gelled.

You can get or add at anytime a heated bowl for the racor. Thats what I have. However I have not had to use it last winter.

The only time I had cold diesel problems was when I had the Gasoline sock replacement on my FSU, too small too allow thick diesel through it. Needless to say that got eliminated.