Fuel and firewalls

[jjbardell]

I'm searching opinions on what part should I order to penetrate the firewall for my fuel. I'm not using a gascolator so I need to transition from a solid line off the tank to a -6 braided to the aero injector.

Also, what micro or recommended fuel filter is there?

My old plans don't offer any details or guidance.

Thanks. J.

[gammaxy]

I used braided -6AN hose on both sides of the firewall, so this might not work for you. I thought flexible hose might put less strain on the fuel tank connections if the tank shifted slightly or the firewall vibrated, but the flexible hose does add a little strain of its own.

I used a steel 45 degree bulkhead fitting with the 45 degree side in the cockpit. It needs a doubler for the nut to tighten all the way--I made one out of ~1/8" thick aluminum. I rotated it to get a nice smooth curve in the hose from the shut-off valve to the fitting. The hole through the firewall has to be a little off center due to the aluminum angle stiffener in the middle.

Bulkhead fitting: http://www.summitracing.com/parts/FRA-583706
Nut: http://www.summitracing.com/parts/FRA-592406

I used an Earl's Performance inline fuel filter on the engine side of the firewall. I hoped it would have a large cylindrical pleated fuel filter inside for plenty of surface area to catch junk (the body certainly seems shaped for one). Instead, it just has a metal mesh circular filter about the size of a quarter at the downstream end. I've checked it twice in the last 100 hours and it didn't have much in it either time. If I continue to catch contaminants at the same rate (most of the contaminants seemed to be flecks of the plumbers paste I used on the fuel tank connections), I'm pretty sure it would take thousands of hours to block up.

Fuel filter: http://www.summitracing.com/parts/EAR-230206ERL



I made a little bracket for my flow meter to bolt to. I ended up removing the flow meter, so now the fuel filter is attached to the bracket. The battery box would have been better about 1" higher. I ended up trimming the bottom corner to prevent any potential rubbing.

[jjbardell]

That's a huge help. I do like the idea of braided on both sides. Thank you!

[mike.smith]

I used the same fuel filter as Chris. In 125 hours I've not yet found any more than a fleck or two of tiny debris.

I used a firewall fitting from Jeggs (I don't know that I have the model number). Here is how I installed it:

http://www.mykitlog.com/users/display_l ... 216&row=20
http://www.mykitlog.com/users/display_l ... 968&row=18
http://www.mykitlog.com/users/display_l ... 727&row=16
http://www.mykitlog.com/users/display_l ... 251&row=23

I originally had my AeroInjector mounted so the cable connections faced the firewall. But my throttle and mixture cables would bind up due to circuitous routing, so I did like the factory does and rotated the AI so the cable connections face the prop. All ills were solved and cable operation is smooth. But that means the distance from the firewall fitting to the AI is very direct and very short. I do have braided hose, but I elected to put the filter onto the firewall fitting and have the braided hose (very short) between the filter and the AI.

[jjbardell]

Thanks Mike. I feel comfortable with the plan now to move forward. This group is really a great community and I am so thankful for everyone on it.

[sonex1374]

I also used a fuel filter in lieu of a gascolator, and routed my fuel lines as direct as possible. I also wanted the ability to sump the system with a quick drain, so I installed a T-fitting right before the filter and ran another line of SS flex hose vertically down to the bottom of the firewall where I mounted a Curtis quick drain valve. This serves a similar function as a gascolator by providing a vertical length of hose (at the low spot of the lines) for any water or debris to collect in, which can then be drained off before flight. It also allows any trash that collects on the filter screen to fall off the screen and into the sump line.

My fuel system diagram is attached with a depiction of the system and part numbers for everything I used. It's worked flawlessly so far, and I'm completely happy with it.

Additional pictures are located on my website at:
http://sonex604.com/firewall2.html

Sonex1374_Fuel_System.pdf

(155.97 KiB) Downloaded 273 times

[jjbardell]

Jeff. Your schematic is fantastic. Thanks!