Replies to This Discussion

Permalink Reply by Todd Scruton on December 7, 2017 at 8:59pm

I’ve been looking into the same thing. I’m sure the efficiency gained would be well worth the effort. I will probably set up a second engine with EFI and once sorted swap it out. I don’t want to delay my build by chasing “perfection”. The biggest issue I will have when I convert is the return fuel.

• ▶ Reply

Permalink Reply by Carl Orton on December 8, 2017 at 10:52am

Don't take this as gospel, and I thought it was novel when I read it, but I *thought* I saw on the SDS website that, if needed, you could plumb the return line back into the fuel supply line upstream of the pumps.  According to SDS, the return line has little to no pressure on it.  Investigate this fully for yourself, though. I never took fluid dynamics, so there may be a physics-related reason why this is a bad idea.

• ▶ Reply

Permalink Reply by Joe Hopwood on December 8, 2017 at 10:57am

Could this not pump fuel in a circle without drawing from fuel tank?  There must be some reason that every fuel injection system I have seen takes the return all the way to the fuel tank.  Lots of extra plumbing if it was not necessary.

• ▶ Reply

Permalink Reply by Carl Orton on December 8, 2017 at 12:04pm

Your response makes sense, Joe.  Like I said, someone with more knowledge may be out there. I would assume, in ignorance, that even though it might pump in a circle, there would still be a need for additional tank-supplied fuel, which I would, again, ignorantly, be sucked by the pump.

I'm not at wings/tanks part of my build yet, but am intending to run a traditional carb on my O-200. It would be nice to be able to install an aftermarket fuelie system without having to tear the wings apart to retrofit return lines. I really don't want to install "stubs" of fuel line for convenience if I never choose to install such a system.

• ▶ Reply

Permalink Reply by Joe Hopwood on December 8, 2017 at 12:14pm

It would be easy now and very difficult in future.  Perhaps look at it as an insurance policy.  :-)

• ▶ Reply

Permalink Reply by Don Morrisey on December 8, 2017 at 7:03pm

I think the reason (but I'm no expert either) to return to the tank is the heat of the fuel and avoiding vapor lock and secondly (maybe more important) is to give any air bubbles a place to go as opposed to back to the engine where they may cause it to stop.  I did install return lines in my wings and plan to use a header tank that gets four lines going in, two vents and two supply (overkill at 1/2").  I essentially duplicated the system that was fabricated and installed on the One Week Wonder for a rotax 912is, even though I'm installing an O200. If you search rotax 912is fuel injection system you should come up with a series of videos that explain the design and testing on the system.   Adding the vent lines from the tanks was minimal work and going to a header tank, IMO, simplifies the fuel system in the Zenith system where there is only one supply from each tank...a header will avoid any loss of fuel pickup depending on your attitude (not that there aren't many flying that just have the standard one supply line from each tank w/no header tank)...but installing the additional vent lines and header tank is low time and dollars in exchange for me feeling really good about the fuel supply system.  I plan to have the header tank made with an extra bung to accommodate a return fuel line from the engine...I just may install the line to the firewall...because it will be relatively easy to do and who knows when it'll be needed.

• ▶ Reply

Permalink Reply by Don Morrisey on December 7, 2017 at 9:00pm

Interesting.  They have an on line installation manual for an O200 and it actually looks fairly straightforward:

http://www.sdsefi.com/contiman4.pdf

I almost went with EMags for my O200 and still might.  Interesting read and lots of info from this builder/flyer on installing EMags in his O200 powered KR2:

http://jeffsplanes.com/KR/2013_Flight_Testing.html

• ▶ Reply

Permalink Reply by charlie rosenzweig on October 18, 2019 at 10:18am

Carl,

I have an SDS EFI on my RV6A project.  I am not flying yet.    But I have several videos of my installation on Youtube and a thread on VAF with over 62,000 views.

Here is a link to the youtube channel.   https://www.youtube.com/channel/UClPxRh6jXRkYToJmhy9G63A?view_as=su...

If that does not work, just search for Honda R18 on youtube and you should come up with several of my videos. 

I am on by 2nd SDS EFI and I can tell you that I am 100% a fan of it.  The support from Ross at SDS is excellent and the system is very easy to use.   I think he has sold over 2000 units to kit plane owners. 

Let me know if you have any questions. 

Charlie 

• ▶ Reply