Walbro in-line external pump-what pre-filter...what micron size or which model...?

[nvrstuk]

What's everybody's favorite for a pump pre-filter on a Walbro external pump?

Since I'm asking...what micron size post pump filter is most commonly used?

thanks!

 

[toddz69]

Pre-filter 100 micron. Post-pump filter 10 micron. I'm going to be using Aeromotive filters. Not cheap but they're good.

Todd Z.

 

[nvrstuk]

Thanks Todd!

 

[nvrstuk]

So I checked Aeromotive prices and I might have a deal for ya... do you want to sell me your used ones so buying the new ones might be a little bit easier for you...and me??? ;D

 

[ransil]

I use off the shelf prefilters, walmart or advance auto fram G3606 or Purolator F29160

post I use 94 F-150

 

[Broncobowsher]

If you still have a stock fuel pickup it already has a pickup screen which will be good enough. If you have an aftermarket tank (or otherwise lost the filter sock) and just have an open inlet in the tank, than a pre-filter is a good thing. No super filter, just enough to keep the rocks out of the pump. Thus the 100 micron recommendation is good.

You want to minimize the filter restriction going into the pump. The fine stuff will pass through the pump without hurting it. Catch it on the outflow.

 

[pbwcr]

'96 EFI
Walbro pump in the tank with its included sock filter. On the frame rail a stock Ford filter. Same as stock except for aftermarket pump and sump.
'72, 92 EFI
Boshe pump on the frame rail with unknown prefilter. In the tank just a suction tube with no sock. No other filters. Nothing stock on this rig.
Guess I will have to do research for filter ratings.
100 micron before and 10 micron after pump is widely recommended and it is obvious that it is not widely used and with good success.
Pump makers tell it correct. What ever they say is best.
Paul

 

[nvrstuk]

pre- and post...exactly right. Keep any possibility of crud from ruining the pump and then take care of the injectors...

Anybody cut out the access/sending/fuel pump assembly out of a mid '90's Bronco and use it? I'm guessing a mod for adjusting the depth for differences in tank dimensions but just curious if anybody has feedback for doing that.

My in-line pump might be my backup for an eventual in-tank pump. I like the cooling and longevity aspect of having the pump in the tank... but many aren't having any issues mounted in-line outside the tank.

Thanks for the less expensive options for filters. I'm looking at the possibility of a temporary setup and I can't do that with the premium filter$...

 

[TN1776]

Pre-filter for me is the filter sock on my in-tank pump. I had to drop my tank to change the sender and while I was in there, noticed the sock was filthy on the exterior surfaces, but looked spotlessly new on the interior surfaces. Autozone had a replacement sock which was very inexpensive.
Inline filter on the frame rail is the same off the shelf unit that my 2000 Silverado uses. If those filters have kept that truck's fuel system happy for 238000 miles, they should do fine for my rarely driven, EFI Bronco.

I had problems with an inline high-pressure pump (actually 3 of them) but I know I am the minority there. I just had enough and upgraded to an in-tank pump.

 

[ntsqd]

No sock so I made the 100 micron pre using an Aeromotive body and some SS 100 micron SS mesh that I got from a friend in the aerospace filter biz. For the post I'm using the std. 10 micron GM filter with aluminum o-ring bump to AN adapter fittings. The highest priced such filter on Rock Auto was something like $20 (Bosch) and most other brands are in the $10 range. Not bad for a SS bodied, 10 micron filter that was used on every GM EFI for more than a decade and is available everywhere!

External pumps can suffer from vapor lock-like symptoms and that can be hard to cure. I did some research a while back on boiling temperature vs. pressure of gasoline and I wish that I had that info handy still. It came down to even a couple psi pressure drop on the fuel from ambient radically reduced the boiling point. A couple psi above ambient increased the boiling point, but nature not being fair it was less of an increase than the reduction was a decrease. As an example let's say that gasoline boils at ambient pressure (14.7 psi) at 95°F, a 2 psi decrease in pressure (now 12.7 psi) from ambient reduced the boiling temperature to 85°F, but a 2 psi increase from ambient (16.7 psi) only raised the boiling point to 100°F. These numbers are illustrative only, not actual but do show the trend that I found.
This why I'm a fan of as much pressure in the supply lines as you can possibly get, and as little of a restriction in the suction line as well as the shortest suction line as is possible. Just a little pressure drop from a restrictive suction line can cause the fuel to boil in the line on merely a warm day. Presto! "Vapor Lock"!

 

[pbwcr]

Walbro pumps I use come with the sock. Under bad contamination issues in the tank it will plug up and the result is the pump overheats and you get low pressure - no run. Replace the sock and all is good with no measurable damage to the pump. Discovering this was a long experimental process.
So what if I had a 100m filter instead of the sock? Answer - It would plug up probably a 1000 times faster than a sock.
Choose your own poison. Overkill is not recommended.
Final filter: It is correct that any oem final filter used for efi is a great way to go. With all my trials my stock Ford frame rail filter and never plugged up and never caused any injector issues. IMO buy cheap and use plain old hose fittings because the pressure is always less that 50 psi and cheap hose clamps are plenty adequate.
Paul

 

[ntsqd]

Advantage of the external 100 micron filter, IMHO, is that I can easily take it apart, clean it out, reassemble, and be back running in a matter of minutes. Even on the side of the trail, in the mud, during a white-out. Downside is that the suction line is longer than with an in-tank system.

I don't use hose clamps because I've tired of how they chew up the hose and eventually either the end of the hose fails or it needs to be shortened because it's so chewed up. I convert to AN, and run the "Push-lock" or "Barb-tite" type of hose end. Now I can use real wrenches to break into a system without damaging the hose. It isn't a "Braided SST hose" snobbishness, it's a wanting a simple, easy method to break into and then re-seal a system without periodically consuming some of the system's components. As an experiment I've been running the emissions barrier type fuel hose on these fittings. Been working well on one car for over a year, but it's system pressure maxes out at 15 psi. The Bronco also has this, but it's still carb'd while I'm gathering the SEFI pieces.

 

[pbwcr]

Good discussion
My EFi pump with the wolber is in the tank. And after re clogged socks I added a drain plug. Wow what a break thru. Ha.

For sure I agree about hose clamps eating hoses.
Method 1: I always install the hoses with at least a small slack and just cut off the 1/2" or so if undoing is required.
Method 2: NAPA sells replacement bell ends for the stock Motocraft EFI filter. The gadget has a built-in quick release lever and the o-ring has never failed. Wow another break thru. Ha. (attaches via a permanently installed hose clamp.)
You will never imagine the trama of dealing with the fuel issue I had and now have a workable system.
And believe me I did all this in Baja with parts from the US.
Regarding the 100m filter - if the pump requires it then use it. My pumps require a sock and are for use in the tank.

 

[nvrstuk]

My tank is super clean, no contaminants to speak of so I want the smallest (physical dimensions) inlet filter I can get as I'm mounting the pump within 3" of the bottom of the tank on the outside (front, right corner of the tank). This will require a much shorter lift and will keep it farther from the exhaust (thanks ntsqd). So you can picture it better, it should be appr 4" below the rear cross member off-centered of the pumpkin.

I'll extend my tank skid plate to protect it as I have a tendency to rip all things possible from the frame rails. Be amazed what busting through frozen ice encrusted snow does at 20+ mph to fuel lines, electric fuel pumps, brake lines, etc even when mounted above the pumpkin on the rear cross member!

 

[pbwcr]

Use care choosing a pump inlet filter. Pump performance depends on low pressure loss to its inlet. You have the head of the liquid that is being reduced by the pressure drop across the filter. Pump people usually specify the details of the inlet filter. This is why some come with socks and some specify a certain micron rating. Then many in tank pumps are so tolerant of contamination they specify no filter. Call the pump guy.
==========

My tank is super clean, no contaminants to speak of so I want the smallest (physical dimensions) inlet filter I can get as I'm mounting the pump within 3" of the bottom of the tank on the outside (front, right corner of the tank). This will require a much shorter lift and will keep it farther from the exhaust (thanks ntsqd). So you can picture it better, it should be appr 4" below the rear cross member off-centered of the pumpkin.

I'll extend my tank skid plate to protect it as I have a tendency to rip all things possible from the frame rails. Be amazed what busting through frozen ice encrusted snow does at 20+ mph to fuel lines, electric fuel pumps, brake lines, etc even when mounted above the pumpkin on the rear cross member!

 

[toddz69]

Use care choosing a pump inlet filter. Pump performance depends on low pressure loss to its inlet. You have the head of the liquid that is being reduced by the pressure drop across the filter. Pump people usually specify the details of the inlet filter. This is why some come with socks and some specify a certain micron rating. Then many in tank pumps are so tolerant of contamination they specify no filter. Call the pump guy.
==========

I realized a few years ago that my current configuration is probably one of the worst case situations for a pump - I have a stock EFI filter (10 micron?) between the tank and the pump so my pump has probably been working real hard for the past 18 years to pull fuel from the tank. I'm hoping my new configuration will ease that load a bit with a coarser filter and the pump being closer to the tank.

Todd Z.

 

[ntsqd]

As an aside both the FJ60 and the Bronc-up fuel systems are designed with one of these near the tank:
http://www.westmarine.com/buy/mercury-marine--water-separating-kit-with-fuel-filter--1662576

I first used one on the Sub that I took to Baja with LocosMocos for the '01 B1k (in fact the unit on the Bronc-up is THAT filter mount). Brian's mention of tearing things loose reminded me of this filter and the gravel/rock deflector that I bolted to the frame just in front of it. The mount for the filter under the FJ had a deflector incorporated into it. It is much more tucked up under the Bronc-up and I'm not as concerned about the need for a deflector.

I don't expect the HP pump to draw out of the tank and thru that filter so I have a Carter P4070 as a demand/lift pump drawing from the tank & pushing thru that filter.

 

[nvrstuk]

Great lesson here from Aeromotive. We know most of this stuff, it's just important to remember it when working on a project...
http://aeromotiveinc.com/fuel-filtration/


Those spin on filter assbly's work great! As an ex-"boat rigger" from a previous life I installed many of those. I always run one of those on my boat and always carry a spare filter on board... they can trap/hold a ton or crud...

 

[ntsqd]

Not to mention that with a quart or so of fuel in it that it acts a bit like an accumulator. My HP pump will be within 6" of line from it and this one will be getting a "draw straw" mod.