David-aviator
Well Known Member
I've made three flights with the newly installed EFII single electronic ignition and am getting acquainted with it. The system is different from other EI units available in that it is part of larger package, namely electronic fuel injection which can be added later. The timing curve is embedded in an ECU built by Ross Farnham and programmed by Robert Paisley at EFII. The ECU controls fuel injector timing in addition to ignition timing.
www.sdsefi.com/racetech.htm
www.flyefii.com
I went one step beyond what is needed and installed an air/fuel ratio monitor system. Granted it is not the total story re A/F ratio as it monitors #4 only but it is much better than no indication. If EGT's are peaking at nearly same number, the A/F ratio number from #4 will be in the ball park. I also installed the fuel injection programmer and can monitor timing change activity. (plus a raft of other parameters if the total package is installed)
The first thing apparent is full rich mixture (with the AFP horizontal injection system) is very rich at take off power. It is reading 10:1 which I believe is wasting fuel. Yes it cools the engine but how much cooling is needed on a normal day? Same observation on climb. I've started pulling the mixture right after take off to get it to 12:1, the change in fuel consumption is significant.
i"ve done several WOT runs at a DA of 8500' (as computed by the GRT Sport EFIS system) and it appears top speed may be one or two knots more than with 2 magnetos but that is subjective as DA is difficult to determine. I do know engine RPM is at or higher than before running at about 2750. Fuel burn is 12.4 at 100 ROP.
It has been well established over the years, EI shines at higher altitudes. This system will advance to a conservative 30 degrees BTDC and will burn fuel more efficiently with its long spark duration. At this point I estimate CHT is running about 20 degrees warmer than before but that is total estimation as I have no recorded comparable data. My cooling system works well, the max CHT I've seen before doing a similar WOT run was around 390, yesterday I saw 402, the day before 405. Less fuel going out exhaust, higher CHT.
At idle after start, timing is at 15-20. It advances to 30 when setting take off power and then backs off 4 degrees when 28" MP is reached. In climb it begins to advance again as MP decreases.
The engine runs smoother with EI. It starts easily and idles nicely at less than 500 rpm. With a FP prop this low idle setting makes quite a difference in managing speed on final. I usually carry a little power to hold 60-65 knots with 40 flaps. It cuts down on ground effect coasting also. Early in the flight test program idle rpm was about 800, that is way too high. It makes a huge difference in managing speed with a FP prop.
www.sdsefi.com/racetech.htm
www.flyefii.com
I went one step beyond what is needed and installed an air/fuel ratio monitor system. Granted it is not the total story re A/F ratio as it monitors #4 only but it is much better than no indication. If EGT's are peaking at nearly same number, the A/F ratio number from #4 will be in the ball park. I also installed the fuel injection programmer and can monitor timing change activity. (plus a raft of other parameters if the total package is installed)
The first thing apparent is full rich mixture (with the AFP horizontal injection system) is very rich at take off power. It is reading 10:1 which I believe is wasting fuel. Yes it cools the engine but how much cooling is needed on a normal day? Same observation on climb. I've started pulling the mixture right after take off to get it to 12:1, the change in fuel consumption is significant.
i"ve done several WOT runs at a DA of 8500' (as computed by the GRT Sport EFIS system) and it appears top speed may be one or two knots more than with 2 magnetos but that is subjective as DA is difficult to determine. I do know engine RPM is at or higher than before running at about 2750. Fuel burn is 12.4 at 100 ROP.
It has been well established over the years, EI shines at higher altitudes. This system will advance to a conservative 30 degrees BTDC and will burn fuel more efficiently with its long spark duration. At this point I estimate CHT is running about 20 degrees warmer than before but that is total estimation as I have no recorded comparable data. My cooling system works well, the max CHT I've seen before doing a similar WOT run was around 390, yesterday I saw 402, the day before 405. Less fuel going out exhaust, higher CHT.
At idle after start, timing is at 15-20. It advances to 30 when setting take off power and then backs off 4 degrees when 28" MP is reached. In climb it begins to advance again as MP decreases.
The engine runs smoother with EI. It starts easily and idles nicely at less than 500 rpm. With a FP prop this low idle setting makes quite a difference in managing speed on final. I usually carry a little power to hold 60-65 knots with 40 flaps. It cuts down on ground effect coasting also. Early in the flight test program idle rpm was about 800, that is way too high. It makes a huge difference in managing speed with a FP prop.
Last edited:
