Why not use the OEM PCM/ECU?
Why don't you just use the Honda PCM/ECU?
I do get this questions a lot. The OEM PCM has a lot going on inside, and it requires a lot more sensor input than what I need or want. For example, it is used to seeing Transmission activity, Vehicle Speed, and lots of emissions data like EGT, EVAP, Catalytic Converters info and much more.
So why not use an aftermarket ECU programmer. Well aside from the fact that I am super happy with SDSEFI, there are other aftermarket PCM and PCM programming tools. I have talk with the folks at Hondata, Ktuner, Motec, Link and more. Some of these are viable options, especially if you use a port injected engine, and not a late model GDI (gas direct injection).
If you are considering an aftermarket PCM/Programmer and you are not familiar with them, get some advice from an experience programmer and make sure they know your "unique off road" machine will not have a lot of the typical sensor data. Some sensors can be "turned off" Others cannot. MOTEC is the leading automotive standalone PCM but they are expensive. They start at $4k and go up much higher.
One of the more out-of-the-box thinkers said that most of these engines have cousins who do duty as marine engines. Yes. Very true, in fact the Honda K24, one of the most venerable honda engines has been doing just that for over 15 years. There is some very sound logic in considering this route. While some of the engines do have some changes in the design from their land based siblings, now days it is rare, and the changes are usually more beneficial to an aviation adaptation to boot. A marine PCM would not be looking for Transmission and speed data. But they do look for other controls and I am not familiar with their design layout. But the Honda Marine BF150A has excellent specs and the PCM wiring schematic is readily available on line - its even included in the owners manual. So the theory for those of you who are not afraid to innovative, you could use a BF150A Marine PCM on a land based K24Z series as it would not be required to look for transmission data etc. But you would still need an after market re programmer like Hondata, or Motec and it might be possible. For me, I am going to stick with SDSEFI because it is proven and the support is great. The only downside is that, currently, SDS does not support GDI and all but one Honda (the R18) is not GDI. So it you are looking to get one of the more late model Honda for your rocket ship. Do your homework!
My project is looking good. I have had my head (feet, arms, back) deep in to the electrical work. Nothing fun to report, other than it is going well.
On a side note. This thread passed the 50,000 views milestone last week! I have to admit that is a big number. Surprising too. There are not a lot of folks who comment, and I suspect there are quite a few lurkers who for various reason don't want to comment. If, by chance, it is because of ridicule from other members of VAF that would be a shame. I hope that is not the case. Regardless, as long as people seem interested, I will post. I realize this is not the type of venture than most builders would want to tackle, but certainly by the viewers, it is certainly something people are interested in reading about. For me it is what I enjoy the most. Experimental aviation does include the forward part of the firewall too!
Let me know if you have question, comments, or respectful disagreements, all welcome.
Good flying to you all.
Charlie