AFP inline fuel filter or gascolator?
 

I am wondering about the AFP inline fuel filter. Cleaning it annually without spilling and stinking up the cockpit and the lack of water seperation. I am thinking about plumming it out of the system and installing a gascolator on the firewall which solves both problems. Any thoughts?

I put that filter on the forward side of the firewall, but I got my kit before the "package" of spaghetti was offered. Water separation is not really an issue with FI. Water is an issue for carbs because the driving pressure differential in a carb is very low, and the higher viscosity of water as compared to fuel might be enough to stop the water from being pulled through the jet. However, in a FI system, water will be pushed right through the system.

I mounted an in-line (AFP) filter on the engine side of the firewall of my -4. It is a pain to access and makes a mess every time I open it to check for debris. When I built the plane, I considered a gascolator and bought the Andair unit, but elected to go with the in-line filter. I like the gascolator, but, ideally, the filter should be before the boost pump. I did not do this in my plane and regret it. I have considered using a pair of in-line filters spliced into the fuel lines that go to the selector, but can't stand the thought of grounding the plane long enough to make the change.

Good luck,

Dean Pichon
RV-4/400 hrs
Bolton, MA

I was talking to the tech help at Vans Friday about this. My RV-8 has an 180 hp IO-360 and does not have a filter but does have a gascolator. He says that as long as you have one or the other you're ok, but with the higher boost pump pressure in a FI application, the gascolator is an opportunity for a leak. If it doesn't leak with the boost pump on he said it's fine.

The higher pressure boost pump is apparently why Vans and Airflow Performance prefer a filter on the low pressure side of the pump. The connections and assembly are therefore exposed to only atmospheric pressure and are less likely to leak.

What others have said about water being less a problem with FI is also true. A little water will go right on through. Dirt is the bigger problem. Something has to be in the system to keep dirt from clogging something up.

Filters Only
 

I have a filter in the line from each of four tanks, no gascolator, no problem in 400 hours.

Bob Axsom

And Van's prefabed fuel pickups, have a good stainless steel straining screen to start with.

L.Adamson

AFP Filter
 

Gascolators and/or the pic up screen are no comparison to the AFP filter. Perhaps the AFP folks who cruise this forum can chime in, but the AFP filter is extremely fine and has a huge surface area. The pic up tube is very course in comparison and most gascolator filters have very little surface area for filtering and are designed so if they plug up, they still will pass fuel with no filtering.

I disconnect the fuel hose at the Servo, hit the boost pump until the fuel in the line is expelled, you can hear the pump when it starts to go dry. You might spill a drop or two, but very little fuel spills in the cabin from my experience.

As always, my two cents.

AFP or gascolator
 

Thanks for the replies. Ya godda love this web site.

Not all gascolators are the same! Those from Andair outperform the others and make checking/cleaning the filter easy.

Pete

We put our fuel filter between the tank and the fuselage.