Excellent product! I've been running one unit on my RV6 with a high compression IO-360 for two years, and I can't wait to put on the second unit.
This is by far the most tested aircraft electronic ignition ever made. The unit was subjected to much more testing than their certified competitor (by a factor of 7!), tested thoroughly by Lycoming, and has passed with flying colors. The development of this system is a great example of how the FAA bureaucracy can ruin a company, but they persevered.
What it is: This is an easy to install, magneto replacement, that provides altitude compensated ignition advance within the detonation safe zone. In a low altitude, high manifold pressure, high power climb you are going to get 25 degree advance (base timing) just like a magneto. However, it will advance up to 38 degrees once your are in the detonation safe zone below 25" manifold pressure. Installation is just like a magneto with the addition of fused power directly from the battery, and a manifold pressure connection. You use the magneto gear, and the existing spark plug harness. It will last the life of the engine, with no maintenance. Only moving part is the geared shaft on a 50,000 hour bearing that only acts as a trigger. No external boxes or electronics, using existing ignition switch.
What it is not: This is not an electronic ignition for the "hotrodder" that wants to tweak the ignition curve and push the boundaries of detonation with their high dollar engine. Automotive engines have a "knock" sensor that advances the timing until is detonation is sensed and then backs it off. Piston aviation engines have no such system. So the philosophy was to build a KISS principled unit that is easy to install. You cannot adjust the timing curve, which also made the FAA happy during certification.
What it does: No 500 hours inspections, no impulse couplers destroying themselves and falling into the engine, no AD's, plug and play installation. I have easier starts, hot and cold. I can easily run lean of peak, seeing 7.5gph at 10,000' 165knots TAS. It runs so smooth that your mixture essentially becomes a throttle. I even know of carbureted O-360's easily running LOP with this ignition.
What to expect: Any electronic ignition system that burns the mixture more efficiently is going to highlight any deficiencies within your powerplant system. The CHT's will run slightly higher (10 degrees, below 25" MP) as you are extracting more BTU's from the fuel. In my case I found inefficiencies in my baffle that I corrected. I also needed to re-tune my GAMI's as I'd never been able to run this far LOP with mags. Finally, I discovered I had some tired spark plugs that needed replacement.
Bottom line is that I have a engine life span ignition system that costs just a little more than a magneto overhaul, makes my engine happy, and allows me to run more efficiently. I'm going to install my second Surefly SIM as soon as my RV6 comes back from the paint shop. I think you will see further product development from Surefly in the near future.
Who am I: I've been in the homebuilt game since the early 90's. My first project was a Thorp, and I've owned or flown just about every RV. I'm an A&P and an airline pilot. Full disclosure, I live in Granbury and have followed the development of this unit from the start. They are the same group that brought us Skytech and Plane Power, and are well funded. They will be around for a long time. I have no financial connection with them, and had to buy my units just like everyone else. I'm not an ignition expert, and I'm sure that those individuals can pick away at my comments.......but you get the jist.
Fly safe!
Jimmy