Now that I’ve got some real solid time(110 hrs) on the plane over the last 7 months, I thought I would do a write up on the EFII System, my experiences and how I set up my electrical system because of it.
With the combination of a Barrett engine, the Full EFII and a 3 blade MT prop, I will say, that our plane is smother that any single engine piston I’ve ever been in. My wife has flown in planes her whole life with her parents, and she is always amazed at just how smooth it is. It starts in just a couple blades like a car, and shuts down with zero flutter.
In flight, I’ve found the system to be very simple and extremely flexible. Because out engine is pushing 300hp, I have found that unless I’m at altitude where it’s quite cool, that at optimum power settings (13.1 Air/Fuel ratio) that I can get my CHT’s up over where I’d like. I have my yellow band set at 410-425, with 425 being redline. I like to keep them below 400 obviously. However, running rich or LOP reduces the temps quite a bit. I’ve been through all the steps and have dropped my temps a bit, my baffling is as perfect as you can get. Unfortunately I did not put in a cowl flap, I MAY do that during condition inspection…☹ After the engine was well broken in I started experimenting with LOP operation (Let’s not have that argument here, to each his own). I have not mapped the fuel delivery to do it automatically yet as I’m still trying to see all the situations that could occur and really learning the plane. Since I’m rarely in a hurry, I can use LOP an not mind a little loss in speed.
In general, at altitude (Above 8K) I can run about 25 deg LOP with my CHTS all down around 350, at 155KTAS on 9.5-10.5 GPH depending on temps and humidity’s. While the difference in smoothness between “Normal ops” and LOP is noticeable, It’s only noticeable to me and my wife because we know the plane so well. The difference in feel is almost negligible.
I’ve gotten my fuel dialed in to run rich during take off and climbs to keep things cool, and to richen back up at low MP for descents to prevent any back firing (When I pull the throttle to idle coming into the pattern or on approach).
So really, set the knob it in the middle for taxi, take off and climb, then, right now I’m leaning to LOP manually once in cruise. as soon as I’m ready to descend, I set it back to the middle position and it takes care of itself. Once I’m certain I know every RPM and MP scenario that I’d want LOP operation, I will change the mapping to automate that. (However, as we all know, during a flight temp and pressures change even thought your altitude hasn’t, so some small tweaks are needed to keep it where you want it.
I’m running 30 deg advanced timing (At higher rpms with a retard mapping built in based on MP). I switched it to 27 for a while and it seemed the temps were a little better. My next experiment is to do some comparisons of speed and fuel of the two timings. Again, that takes time. I’m so busy with work and when I want to fly, I want to go have fun or go somewhere. I rarely have a day to just go punch holes…
As for my electrical system: I’ve shared my schematic with a few other builders. It’s not complicated and I’m not re-inventing the wheel. I AM using the EFII Buss Manager to simplify my main buss and essential buss. I’m not using VPX(I chose to go with a combo of Circuit breakers for mission critical stuff, and fuse blocks for stuff that should never be reset in flight).. A la Bob Knuckoles. I put a lot a lot of thought into possible failure scenarios. Included are some pictures of my panel. We have 2 batteries, 2 alternators and some of the avionics have their own back up battery. Since the EFII system is dependent upon electricity, I wanted to make sure there’s always electrons to keep the big fan spinning. Our #2 alternator is vacuum pad mounted, so in theory if the engine is running it’s generating power, if its generating power, the engine is running and so on. The two batteries are independent, and the likely hood of both going down, while possible, is slim. With the buss manager, if there’s 12v somewhere in the system, it will get it to the essential buss, and keep the Fuel and Ignition running. So, if we lost alternators, and we running on just battery power, I created a “load shed” scenario. I have 2 switches with special labeling for the accessory buss and the avionics buss. Flipping those two switches, kills any not mission critical components and takes me down to one screen and one com. That way I can maximize battery life until I can get on the ground.
Another tweak I made to the system was a “Both Fuel Pumps” switch.
Here's my thought: The buss manager has a set point to set the pressure at which if Fuel pump #1 wasn't keeping enough pressure, it would switch over to pump #2 automatically, but what if there was an issue with #2?, you have no way to force the bus manager to run pump #1. This way if for some reason I needed to, I can send power to both pumps if that's what I had to do to keep the big fan spinning until I can get on the ground.
So, that’s the info on my experience with my EFII system I love it. I would do it again.
Between the hardware and system being top notch, and support from Robert, you really can’t go wrong. Dialing the fuel mapping into your personal style takes some time, but it’s pretty close right out of the box….
Heres the Load Shed switches: With the "Both Fuel Pumps" switch under the Quadrant.
Here's the ECU select Switch, which decides which ECU is running the Injectors. With a Dual ECU set Up, one ECU runs the top plugs and one the bottom. I have locking toggles to control power off the ECUs. These are "Run UP" switches. Only used during to run up to verify each ECU is running independently of the other...