I did not build my Onex and am having issues with what I believe is vapor lock.
The fuel line comes out of the firewall and does a loop up before going down to the aeroinjector
Also, the fuel connector on the injector is very close to the exhaust. The injector is mounted so that it is parallel to the firewall. This places the inlet less than an inch from the exhaust.
Seems like a very bad idea to me, but don’t know hat the plans call for on routing the fuel line and orientation of the injector.
Anyone know what the plans specify or have a picture of how your fuel line is routed and the injector oriented?
My AeroInjector is backwards compared to most, as I did my own reverser to use Cessna style controls.
The sensible thing would be to use Sonex controls, turn your AeroInjector so the cables connect near the firewall and use an angle AN fitting to get the fuel line a straight shot from the firewall. Try and make the fuel line only go down from the tank to the AeroInjector with no rises or dips.
It would also help to insulate the fuel line in the engine compartment and wrap the exhaust tubes in heat resistant material. Your goal is to keep the fuel in the line cool enough at all times to prevent vapor lock. It also helps to route a fresh air blast tube to blow on the fuel line. Another thing whenever you land if you intend to take off again any time soon to open the oil filler cover door on the cowling to allow the hot air to escape. Or, you could replace the aeroinjector with something like a Rotec tbi and be done with the whole issue.
Ron makes really good points that a lot of us probably take for granted after all the discussion on the old forum. Of course your fuel lines should have fire sleeve, and what I did for insulation was to add a second layer of larger fire sleeve over the top of the first. I wrapped my pipes with this stuff:
Lots of options for wrapping exhaust pipes. Wear gloves when you handle it though.
One other thing I did, like others in the community, was to add fresh air induction to the aeroinjector. Besides turning off the perpetual carb heat, the aeroinjector gets cooled from the inside out. This was my best performance mod and also made it happier when pulling away from the pumps after a heat soak. The important thing is to not pressurize the inlet with ram air. The RV guys do use ram air but if you pressurize the aeroinjector fuel outlet without pressurizing the vent to the tank, then the back pressure will cause it to lean out. So it is more of a fresh air supply than ram air. Here is a link to Wes’s thread on the wayback machine:
Here you can see my exhaust wrap and if you look close, the fire sleeve over the fuel line:
The Rotec looks cool. I recently had a chance to buy one. It looks like it has better fuel distribution/vaporization. But honestly the aeroinjector works great for me.
