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alpinelakespilot2000

Well Known Member
Following the reasonably positive experience of others, I decided to put my FloScan between the valve and the aux pump in the fwd tunnel. However, after I installed it I discovered that Dynon recommends a filter upstream of the transducer. I didn't leave room to do so but am wondering if I need to rework my lines to make a filter fit.

What's the likely failure mode for not using the filter? Would debris likely clog the transducer (and cause fuel starvation) or would it just make the fuel flow reading questionable?

FWIW, I have an O-320 (no fuel injection).

Thanks.
 
There is talk of which fuel flow sensors have "bypasses" and which do not... and clearly ones which do not will be more vulnerable to stopping your engine. However, in the ultimate case, even the bypass is likely to be more prone to obstruction than straight pipe.

I've just done the test flying on an RV where, despite apparent best efforts, a load of swarf ended up in one tank. Given the extra heart beats incurred with 3 flights returning with limited power *, I would advise following Dynon's advice and filter before any areas vulnerable to obstruction.

Andy

*For info, the swarf visible in the fuel filter after these flights was considerable, but not enough to restrict fuel flow. The problem was the "in line filter" in the injector body - a "re conditioned" unit. The size of particles required to restrict flow through this got through the filter (Airflow) and were probably not visible. They made the filter very hard / impossible to blow through, and restricted fuel flow through this filter with the electric pump on to approx 50% of that with the filter cleaned... which was done with an ultrasound machine(?) We suspect that filter might have had some corrosion on it which made the already fine holes somewhat smaller? It's being replaced!
 
Thanks Andy.

Does anyone have any recommendations about what would make for an appropriate fuel filter to use just upstream of the fuel flow transducer? I've checked Spruce, but am not sure exactly what I'm looking for in terms of type and micron level.

Also, if anyone else has pictures of their installation, especially how they modified the center tunnel (if at all) to fit everything in, I'd MUCH appreciate it.
 
What I use...

Flow Ezy MODEL 3ILA - 5 gpm / 250 psi / 5.2 oz. ANODIZED ALUMINUM PERFORMANCE RACING FILTERs - Increased volume means more flow. This filter package sports the excellent design of the ILA and 2ILA and combines that technology to create a filter kit that boasts a 5 gpm rating with a minute increase in volume and weight. 74 micron filter.
 
Thanks Walt. Couple questions:
1. Where did you get it? (can't find it in Spruce)
2. Why did you choose the 74 micron version? (The 31A has multiple versions, and I don't know one from the other.)
2. How far upstream is your filter from the transducer? (Dynon suggests 6 inches of straight run in and out of the FloScan. Does having a filter immediately upstream contradict this requirement or is the six inches just meant as a recommendation or prohibition against bends or elbows?)
 
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Does anyone who has used two filters (1 on each side) between the tanks and fuel selector have pics showing how and where they installed them? It would be a retrofit for me so access and ease of installation is important. I'm thinking the most logical at this stage is fwd of the spar under the covers, but perhaps in the wing root if I don't need to do a lot to support the filter body itself.

Also, I'm looking for a bit smaller filter than the Flow-Ezy 3ILA. Whatever filter I choose, I will be using a 74 micron stainless steel per Floscan instructions. At 4gpm, and 12" of surface area would the 2ILA be appropriate or do I really need the 5gpm and 20" surface area of the 3ILA? http://www.flowezyfilters.com/image_assets/Motorsports Catalog 2009.pdf (see p. 2-4)

I'm always reluctant to make any modifications to something as critical as the fuel system, so thanks for the help. (One of the disadvantages of putting the Floscan in the cabin.)
 
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Walt said:
You can get them direct from Flow Ezy...
http://flowezyfilters.freestarter.com/

(6T is the fitting size you need, filter size is 74 micron recommended size from flo scan and the pump makers)

I put mine right after the fuel selector on the floor.
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Whoever you get one from, be sure to specify Flourosilicone or Viton O-ring if you plan on using unleaded gas. I believe that Bendix [and all subsequent owners of Bendix fuel injection systems] specify a 74 micron [approx. .003"] filtration. That should be more than adequate for a carburetor, as they are not as sensitive to small debris in the fuel.
Charlie
 
alpinelakespilot2000 said:
Also, I'm looking for a bit smaller filter than the Flow-Ezy 3ILA. Whatever filter I choose, I will be using a 74 micron stainless steel per Floscan instructions. At 4gpm, and 12" of surface area would the 2ILA be appropriate or do I really need the 5gpm and 20" surface area of the 3ILA? http://www.flowezyfilters.com/image_assets/Motorsports Catalog 2009.pdf (see p. 2-4)
Click to expand...



I'm using a 2ILA-6T-40 in my O-320 with no problems. Photo here. If you use two filters mounted upstream of the valve, you'll have to drain the tanks to remove the filters.

Tony
 
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chaskuss said:
Whoever you get one from, be sure to specify Flourosilicone or Viton O-ring if you plan on using unleaded gas.
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Viton o-rings. Good point. Will likely experiment with mogas in the future.

Tony Spicer said:
I'm using a 2ILA-6T-40 in my O-320 with no problems. If you use two filters mounted upstream of the valve, you'll have to drain the tanks to remove the filters.
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Thanks for the first-hand experience Tony. I think I'd just have to make sure that the fuel in the tanks was lower than wherever I installed the filters, right? Particularly for the taildragger, I think I could mount them just forward of the spar (on the RV-9) under the covers where they would be pretty much the same height as the fuel selector and well above the tanks. Those smaller 2ILF filters might also fit in the wingroots without too much effort, but I'd probably need to find a way to support them there.

Still trying to decide about 2 upstream of the valve or 1 just downstream of the valve before heading into my Floscan. Kind of trying to avoid a single-point failure issue, though I'm not really sure if that is an issue with a quality filter like a FlowEzy with 74 micron stainless screen. I know just enough to know what I don't know!:eek:

Thanks again for all the help.
 
I placed my filter http://www.summitracing.com/parts/AEI-12316/ at a 45* out from the base of my stock Van's fuel valve with HD brass fittings. The service end of the filter is facing down for easy cleaning. In this position, the filter takes up almost none of the run to the firewall. You have plenty of room for your straight run to your flowscan, and plenty of room for your pump.

I don't have a fuel valve cover. It's really not needed and it is just another cover to remove for inspection. But you may need to alter your cover if you mount your filter there. This is a 100 micron ss screen made for laced auto fuel. I am using a carb.
 
Worse case you would have to remove the filter with full tanks. The filter would have to be higher than the filler cap on the tank (assuming topped-off) to prevent gravity-flow. This would require that the filters be located above the spar in the cabin (don't forget the wing is not flat). I would suggest you just stick to a single filter after the valve.


alpinelakespilot2000 said:
Viton o-rings. Good point. Will likely experiment with mogas in the future.


Thanks for the first-hand experience Tony. I think I'd just have to make sure that the fuel in the tanks was lower than wherever I installed the filters, right? Particularly for the taildragger, I think I could mount them just forward of the spar (on the RV-9) under the covers where they would be pretty much the same height as the fuel selector and well above the tanks. Those smaller 2ILF filters might also fit in the wingroots without too much effort, but I'd probably need to find a way to support them there.

Still trying to decide about 2 upstream of the valve or 1 just downstream of the valve before heading into my Floscan. Kind of trying to avoid a single-point failure issue, though I'm not really sure if that is an issue with a quality filter like a FlowEzy with 74 micron stainless screen. I know just enough to know what I don't know!:eek:

Thanks again for all the help.
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