Greetings out there..
I’m thinking of changing half my ignition to electronic on my Lyc 0-320 engine in my -3B.
There’s a few choices out there and just want to get some feedback on preferred systems ?
Thanks…
This topic can be opinionated and passionate. I have my bias but I'll be transparent.
1) ALL EI's do basically the same thing. Give a "fatter", "hotter", "long duration" higher spark energy over a magneto. One prime advantage over magnetos. Spark energy can only be so much. Anything above what is useful is wasted.
2) ALL EI's have some function to advanced timing at lower power (lower MP and RPM). This is another prime advantage of EI's over magnetos. Aircraft EI's use simple RPM and MAP to advance. Cars also use O2 sensor and KOCK sensors with other inputs. For aircraft engines operation at fixed RPM most of the time not needed or can not use KOCK sensors (too loud air-cooled) or O2 (leaded gas). How a brand of EI schedules timing varies. Most can be adjusted, one can not.
3) Simplicity of EI's is another prime advantage of EI's. No moving parts, points or rotor/distributor cap. They all use some type of magnetic or hall effect sensor to trigger timing of spark. Some use magnet in ring gear holder "flywheel" with pickup mounted to engine. Others mount the mag/hall effect sensor on the accessory case, driven by magneto drive (PMag, Surefly, Lightspeed optional mag drive trigger). With these only wear part is the gear/shaft/bearings, but those are simple and reliable, well proven with magnetos.
4) ALL EI's need battery power except for one, which has self powered ability. So your option is have standby power for emergency or run one EI and one standard MAG. 80%-90% of the benefit in regards to performance of EI is achieved with one (1) EI. If you run a Mag with EI the Mag is going along for the ride once the EI starts advancing, however you get that self powered redundancy. Back up power is more weight (extra battery) and more wires and switches. Not a big deal. One brand of EI has built in backup power switching but you still provide that backup battery.
5) Almost ALL EI use automotive plugs and adapters verses MASS ELECTRODE aircraft plugs. Difference? Auto plugs (usually NGK) allow wider gap to take advantage of the larger spark ENERGY; Aircraft plugs are very expensive. NGK's are very inexpensive. Auto plugs is another prime advantage of EI's over magnetos and, larger spark energy fires across a larger gap.
6) Two brands of EI's have an option for EI + EFI (electronic fuel injection)
, SDS (Canada) and EFII (USA). Both offer the EI only option.
7) Some offer both an experimental version and STC version that can be used on standard cert aircraft. (Not a factor for RV builders but worth mention. As with most things where you have non Cert and certified versions of a part, the Cert version cost more. However in one or two cases I think having their experimental units based on certified versions limits them, in my opinion.
8) Top or popular EI brand names that come to mind in my causal order of preference (I have dual P-Mags):
E-Mag (P-Mag) - Feature mounts direct to and driven off engine, self powered over 900 RPM, ease of wiring and installation, well made and supported with service history. Negative of checking bearing every year is a no brainer and over blown, but it is a factor, but not a big deal IMHO. It is installed and you forget it, like a MAG, although recommended runup procedures recommends checking L & R for both operation and L & R for self power. Brad and customer service is top notch. There is a 3rd party company EI Commander that allows cockpit monitoring of P-MAG. Again I don't want to mess with my EI after set up. BTW people claim the advance is too aggressive? It is easily adjustable, but base timing or programing with laptop. This is the easiest to install and performance is as good as any other EI. Although marketing will say otherwise. Again limit to how much energy you can use or need. More is wasted. People get triggered (pun intended) over the manufacture recommendation to check the shaft bearings every condition inspection. It is not big deal and they are reliable. Some do not do the inspection. Some claim the 2nd party in cockpit EI Commander that allows monitoring the PMAGS in flight can indicate bearing wear. Some do NOT check the bearing every condition inspection. Last early teething issues were long sorted out. This is a mature design. I will disclose I bought mine 2nd hand from a builder selling project. So I got a sizable discount. LAST Brad and customer service TOP notch.
SDS - Ross has posted extensively about his development here on VAF. It uses flywheel timing pick ups. This is his 2nd generation and since released made more changes. The look of parts are great. Canada, shipping support may be a small issues. For this to work you need a large pulley ring gear "flywheel" and drill and mount magnets. Not a big deal. However you do have more wires, external brain box, wires to coils. If workmanship and routing of quality aircraft wire with good connections, it should be very reliable. However this is battery powered so you will need back up. I like Ross included backup power input into his system. This sets it apart from other battery dependent systems. However back up power is fairly easy to add to any EI. Backup power regardless requires an extra BATTERY and weight (but not too much). Ross from his post an exchanging comments on other forms is solid and should give great customer service.
Lightspeed - Klaus has been around a long time and it features CDI, Capacitance Discharge Ignition. It has ability to adjust timing advance in flight (which could be good or bad). I have talked to Klaus and liked talking to him. I never owned or operated his product but many have over the decade or two he has been selling his EI. He has the OPTION to put the trigger pickups in the magneto drives off accessory case vs. flywheel pickup. NOTE CDI is unique to Lightspeed, all others use "INDUCTION" ignitions. You can research the pros and cons. CDI has advantages, but not sure it is taken full advantage of in a slow RPM 4 stroke aircraft engine. Klaus has had complaints from, comments I read over many years. I have talked to him as potential buyer and found him helpful and very knowledgeable.
Surefly - New kid on the block. Came out with certified unit out the gate. Not sure if they can run only with magneto in other hole or they have STC approved backup power. They are NOT self powered and do not allow user programable timing advance curve. You can select fixed timing. They do only offer recommend and only offer harness for aircraft plugs. This is unvaried but a source says based on the components they use, spark energy is on the low end for an EI. but more than magneto. This may be why they only recommend Aircraft plugs (which are easier to fire with smaller gap but smaller spark); Or it could be a nod to being certified and they can't be bothered with variations. They do look pretty. However if I am going to mount something off accessory case I want it self powered (PMAG).
Electroair - This is the grandchild or the original Rose electronic Ignition. The current design is nothing like original which was clever but crude by today's standard for experimental EI's. The new design is aircraft quality. Their claim to fame is they have approval to be installed on standard Cert airplanes. I talked to one of the owner not long ago by chance. Nice guy. They know airplanes. They also claim extremely high spark energy. Again limit to how much you need or can use.
EFII- know very little about them, but their website is impressive marketing. I think some VAF Forum member or members have this brand. I also called them and got interesting info I can't verify. They claim the hottest of hot sparks. They also offer EFI (fuel injection). Interesting.
NOTE ON ADV....With fire breathing High Compression Engines detonation is a real concern. That is why Mags are run fixed at 25 BTDC or less typically. That is fine at full power but at altitude at 65% power, that spark is late, not very efficient. ALSO magnetos have to jump three GAPS. One is the rotor to the cap. The other is the spark plug. The last is the points. At low atmo pressure when flying at high altitudes you can get arching of the points. That is why there are pressurized magnetos. Again all that eliminated with no point or distributor.
We have choices!
PS Prices vary but all are expensive, and the difference is fairly small.