Fuel Pump Pre-filter options

[Texasdoc]

Went out to the track today but didn't get to run. I'm pretty sure I got some bad/dirty fuel and that clogged the pre-filter and has damaged my fuel pump. I have ordered a new pump but have a question about the pre-filter.

Is there any reason I can't use those $10 glass filters from Mr. Gasket that I can get at O'Reilly as a pre-filter? They say "Not for use with EFI" but I'm thinking that means "post-pump" due to the higher pressure. In a pre-filter setting there is no pressure, only a small amount of vacuum that will vary depending on how dirty the filter actually is.

The other option is the $70 Holley reusable billet filter. It would be nice to use the glass one to visually check to see if it needs cleaning.

[joyridin']

Is your pump in the tank or external? Sounds like you need something like this:

https://www.holley.com/products/fuel...39ad-264498001

[Texasdoc]

Pump and filters are external. I guess I didn't say, but I figured my question on using an external pre-filter would have meant that my pump was also external. There is an internal baffle to prevent starvation on corners. Not sure how to use the mat on a tank with internal baffles. Also, not sure how it would have helped my situation - bad fuel clogging my pre-filter, damaging my pump.

[joyridin']

Surface area. The more surface area you have, the less chance of clogging the filter. The Holley mats have a huge amount of surface area and they pull from multiple locations within the tank.

Personally, I would start buying gas from another source. 35 years of driving and I have never had that much dirt in any gas I bought.

[scottj]

Originally Posted by Texasdoc

Is there any reason I can't use those $10 glass filters from Mr. Gasket that I can get at O'Reilly as a pre-filter? They say "Not for use with EFI" but I'm thinking that means "post-pump" due to the higher pressure. In a pre-filter setting there is no pressure, only a small amount of vacuum that will vary depending on how dirty the filter actually is.

Those don't have the surface area or the micron rating for use as a pre-filter. I like and use Aeromotive 100 micron pre-filter and 10 micron post-filter.

[Tom Kirkham]

McMaster-Carr

[Texasdoc]

Originally Posted by scottj

Those don't have the surface area or the micron rating for use as a pre-filter. I like and use Aeromotive 100 micron pre-filter and 10 micron post-filter.

Got it. Makes sense. I've ordered the Holley Billet pre-and post filters.
Weird tho - Holley makes one of the smaller/cheaper fuel filters they market specifically for EFI (Part 562-3).

I'll get it installed next week and hopefully get it back out on the road a few more times before the cold weather sets in.

[trularin]

I'll chime in.

My GT40 has a fine filter after the check valve, but before the fuel pump. As I recall it is a 10 or 20 micron paper element housed in a billit aluminum can with AN6s ( might be AN8s ) on each end.

When pumps are hundreds of dollars, I believe the filter needs to be before the pump.

Just an opinion, I hope this helps.

[Texasdoc]

Right. I have a 100 micron filter before the pump and a 10 micron filter after the pump. The question was: are the small $10 glass 100 micron filters you can get at O'Reilly good enough for a pre-filter, or is the $75 filter needed.

The consensus is that those small $10 filters, although they have the right micron filter rating, they don't flow enough fuel for an EFI system. They may be ok for carb systems, but are a no-go on EFI.

[Luce]

It's very important that the pre filter has adequate surface area. it doesn't take much of a restriction to make a EFI pump cavitate, and that's a BAD thing.

I'm using a cheap earl's little inline post filter that actually hangs off the fuel rail. It's just a little sintered bronze (replaceable) element, but it plugs up every 3000 miles. 10 minutes to change, and you get plenty of warning, but changing to a soda can sized fuel lab unit on the frame is on the winter to do list.

Don't skimp on the filters.