Author Topic: Fuel Filter  (Read 3709 times)

Offline BK

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Fuel Filter
« on: February 13, 2015, 05:22:54 PM »
Spud,
 I could use a little filter education. This will be on an injected alcohol system with the tank up front. The filter will be the largest I can fit in between the tank and pump. I'm looking at filters with anything from a 40 micron to 100 micron screen. Is the 40 finer than the 100? Any thought as to what I should use. I know some don't like a filter before the pump but I bracket race and the fuel tank seems to be open all the time.
 Thanks BK

Offline Spud Miller

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Re: Fuel Filter
« Reply #1 on: February 14, 2015, 08:28:08 AM »
 I wouldn't recommend a filter between the pump and the tank...I'd put it on the pressure side of the pump. If you do run an inlet side filter, use something coarse and with LOTS of area or you risk cavitation. If you pour your fuel into the tank through a screen-equipped funnel, then an inlet side filter on the car isn't really required.

 If you can't stand a huge filter on the pressure side of the pump, then a good way to do it is only filter what is going into the motor...that allows a much smaller package because the volume flowing through it is greatly reduced. If you run hat injection for example, you could run a small filter AFTER the metering valve and before your distribution block.

 40 microns is smaller that 100. For mechanical injection, you really don't need to use a filter finer than 80 or 100 microns.

 I have tested the small cone filters that mount inside a fitting...maybe you've seen them. They work! And believe it or not, they don't change the flow a bit (-8 is ok up to 19 GPM) if they're clean. I just could not imagine that those little things would be ok so I bought a few and did some tests...I was wrong. I run one myself on the -8 inlet fitting to my metering valve and check it before every event.

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Offline Curly1

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Re: Fuel Filter
« Reply #2 on: February 18, 2015, 04:18:20 AM »
I use two large filters where it comes out of tank and then it tees into one line to go to fuel pump.