Variable Advance - Any improvement?

rwtalbot · #1 04-20-2009, 11:25 PM

I?m interested to know if anyone has experimented with EI timing changes in flight? I have a set of Pmags and considering if there are significant advantages to firing the ignition earlier than the 39 degree maximum advance and/or other general tuning?

The manual seems a bit vague on what actually takes place under the hood of these things. I assume that the advance is related to RPM and MP, but what the exact relationship is not immediately obvious.

Richard

RV-7A Phase I

Steve Sampson · #2 04-21-2009, 01:16 AM

When the P-mags are turned on, the software initialises to use the A or B curve depending on the jumper. Opening/closing in flight will not change which curve you use.

rwtalbot · #3 04-21-2009, 06:32 PM

Hi Steve,

With EICAD you can advance the timing while the engine is running and you are not limited to the A or B curve. See http://www.emagair.com/EICADII.htm or the latest installation manual for 114 series.

Cheers
Richard

breister · #4 04-22-2009, 02:38 PM

The LightSpeed Plasma III units allow monitoring and manually adjusting timing while in flight. Several of the racers flying Legacys use this option.

petehowell · #5 04-22-2009, 04:03 PM

I used a laptop with eicad to vary the timing curve in flight and settled on a max advance of 42 deg. It allows me to run very lean at lower power settings.

I cruise at about 55% power, LOP, with good results(150KtsTAS on 6GPH) This with an O-320/carb/Hartzell.

I heard some guys we know are working on a way to do this without a laptop. Maybe they will pipe in.....