Electronic ignition - huge benefits claimed

I have been running a CPI electronic ignition system instead of the right magneto for eight months with no issues. The engine (O-320) starts easily hot or cold and I can lean the mixture more than with magnetos. Using the progammable advance switch, I save about 4 l/h with slightly reduced speed, but no change in CHTs. The EI seems to be doing all the work as I have no rpm drop on turning off the left magneto. I have a 4 Ah lithium battery as backup for the CPI.
It is a well made kit and the only problem I had was making up the MSD ignition leads. You need the MSD crimping die to do this properly. They are not expensive, but don’t seem to be available in Europe.




Simon

simon32 wrote:

I save about 4 l/h with slightly reduced speed,

Which would suggest that the MPG is probably unchanged.

I have real life experience with the Lasar electronic mags. With the Lasars it’s very easy to do real-life – back-to-back tests since you can simply pull the breaker on the electronics and it goes back to standard fixed advance magnetos that it is based on.

One real advantage is better/easier starting since the timing is electronically controlled based on engine sensor (probes) parameters, it retards the ignition timing for optimal starting, on both mags, on all 8 (4 cylindres) plugs.

That said, the “performance” gains are minimal or virtually non-existant when you are running LOP.

I’ll look at my logs which calculate litres/100 km, but I think I have gone from about 13-14 to 12-13. The figures are not stable as GPS speed and fuel flow fluctuate. I’ll have to try and average values over a period of cruise.
I cannot do a back to back comparison as the engine runs poorly on magneto when lean. With the CPI I am running 33° advance at 2400 rpm.
Simon

simon32 wrote:

I cannot do a back to back comparison as the engine runs poorly on magneto when lean. With the CPI I am running 33° advance at 2400 rpm.
Simon

Is it possible to change the advance in-flight ?

If so, easy enough to set-up factory advance of 25° BTDC (or what ever it is for that model Lycoming) note FF vs TAS then dialing in 33° and note same.

Yes it is possible to change advance in flight, I’ll give it a try, but I’ll also have to alter the mixture.
Simon

simon32 wrote:

Yes it is possible to change advance in flight, but I don’t think the engine would run well without enriching the mixture as well, sort of reverse of your idea; 33° to 25°. My understanding is that a lean mixture burns more slowly so combustion needs to be started sooner, hence the extra advance. The CPI has a LOP switch which adds a programmable advance (5° in my case) when running lean.
Simon

That’s very interesting Simon.

I wonder if it’s because you’re engine uses a carb vs fuel injected, that makes it difficult to run LOP.

Perhaps the additional timing advance helps to smooth things out ?

If the additional advance means the difference from being ABLE to run LOP or not, then indeed, it would be a great enhancement.

This is how I understand it. Ross Farnham the boss of SDS has much motorsport experience and added the advance switch for aviation use. The engine runs poorly on magneto at my extent of lean. The extra advance does smooth it out. The P-Mag uses a similar principle, but is not so easy to program.
Simon