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EFII - the jury is coming in
Well, I think it's about time that I post a few of my experiences with the EFII system (dual ignition and injection) in the RV-10. I do believe N930M is the first RV-10, and possibly the first 6-cylinder engine, to be flying with the full EFII system. I now have 20 hours in it and feel like I should share my experiences and thoughts on it. I have talked to several people who have shown interest or who are planning to install it in their -10's, so this is mainly for those people, or those who may be on the fence.
First of all, it is a system that required, IMHO, a fair bit more planning than a standard engine with mags and mechanical fuel injection. Even with electronic ignition on one or both sides. I have had a few misgivings of flying -10's with dual lightspeeds, but that didn't last very long. I am actually very much looking forward to flying with the P-mag if/when they ever actually start delivering them. With dual electronic ignition and electronic injection, though, it mecomes much more serious. You really should have dual batteries, at at least dual contactors, if not full dual busses. You really should have dual alternators, or at least it's a very good idea. You need dual fuel pumps because there is no engine-driven pump. if any of these systems aren't redundant and the only one fails, you either are immediately a glider or shortly will be. I know that the battery can keep you going for a while if the alternator fails, but I'm not about to test how long that is. I also think it's very important to have dual ECU's, one controlling each ignition and each can separately control the injection system. I know this becomes a fairly expensive system, but just think, at least it's only 30-year-old technology instead of 80-year-old technology. To be perfectly honest, it took several weeks after first engine run for me to get up the nerve to climb in and go flying. I was very careful to stay within gliding distance of the runway for the first several hours. I just didn't fully understand all that was going on (still don't) and was nervous about being the test pilot for a new system. I have done first flights before, but never with a system that had never flown in this configuration before (at least that I am aware of). The setup was, honestly, a little disappointing. Rob has been fairly available, usually with a call back after leaving a voicemail. I know this system has run on a test stand on more than one occasion, and honestly there were a TON of settings that I had to put in from a spreadsheet that should have been put in at the factory. It was not a mystery that this was going in a -10, so the 300 pages of settings should have been preset. After getting them going and doing the ground testing to setup more accurate fuel mapping, I got to the point where I was willing to take to the skies. Most of the above has been fairly negative, but I think a lot of it is plowing new ground and the time we have spent on this one should help others down the road. I now have 19.8 hours on the system, and it has not missed a single beat in flight. There have been some issues in starting and things like that, but we are figuring out what works. I have not taken the time to tweak all of the fuel maps and settings, but we have things mostly setup and I have been very impressed with the way it has operated so far. Up until the last few hours, I have still told people, "the jury is still out," but I am getting much closer to a verdict now. It took this long for me to get to the point of saying, "I would climb in and fly it to the Bahamas," or "I would feel comfortable putting my kids in it and flying to Kansas." Some things different about the system and the way the engine runs are the following: 1. I can run this engine as low as 400 rpm and it is smooth. I have never run an IO-540 lower than 750-850 rpm because it shakes and shudders. It must be a combination of the variable timing and the fact that the fuel is electronically injected into the intakes for each cylinder, so at low rpm all cylinders are still getting the right amount of fuel. 2. I have done some extensive leaning in flight and have yet to get to the point where the engine stumbles or starts to miss. This is probably related to the same as #1, but it can run amazingly lean in flight and still run smooth. Yes, at a point you start loosing enough power that you give up a lot of speed, but I truly don't think I have seen fuel flows as low in a standard -540 as I have seen in this one, at the same MAP and RPM settings. 3. There truly is no such thing as a hot start issue. I know, you can tell me until you are blue in the face that you have a perfect system that works every time and you never have a problem with hot starts. I have flown probably 20 different RV-10's and many more than that different fuel injected engines, and the hot start is more difficult than a cold start. I have a system that works most of the time, but I have yet to see a system that consistently requires no more cranking than a cold start. The EFII starts hot exactly the same as it starts cold, if not a little better. Since so much fuel is being pumped back to the tank, any time your master is on you have cool fuel in the system. 4. While you can use the mixture knob (potentiometer mounted on the panel) to adjust your AFR (Air Fuel Ratio), there is truly much less mixture adjustment as altitude changes as long as power setting doesn't. I know I have said recently, "if you think you won't be touching the mixture control, you are mistaken," or something along those lines. However, as you get things setup more, once you get setup in cruise with your MAP, RPM and AFR where you want them, you really can fly the rest of your flight that way...INCLUDING THE DESCENT. This is something that really stands out to me. Let's say I am flying along at 12,500 feet at 18" MAP, 2,300 RPM and AFR of 16.7. I can descend to pattern altitude with nothing to touch except the throttle knob. The governor keeps the prop at 2,300 RPM and the EFII keeps the AFR at 16.7 (more or less, but close). With a standard injection system, I have to keep adding mixture the whole way down. I usually find myself going to the rich side of peak as I descend simply so I don't have to adjust the mixture as often. When I see the EGT's start to climb towards peak, I richen up a bit more. If I don't do this and I don't stay on it, I end up getting so lean that the plane really accelerates when I add mixture. With the EFII, you really don't have to touch anything until you are on final, when you are preparing the mixture knob and the prop control for a go-around if you need one. Final thoughts: 1. Would I recommend the EFII system to other people building RV-10's? That depends. Some people just want to fly. They want to climb in and go somewhere and not have to think about it. For them I would say, go with mags and a Bendix, Silverhawk or AFP injection system and enjoy. For those who want to do the tweaking and testing to get a little better performance or better economy, then this just might be the system for you. 2. Doesn't useable fuel decrease because you are dumping so much fuel back in the tank and could start sucking air at a higher fuel level? I burned a tank down until I saw 0 on the Dynon and it took 29.5 gallons to fill back up. I didn't wait until it missed, but it was running solid up to that point. I doubt there is more than a quart of difference in useable fuel, if that much. 3. Would I put my wife and/or children in it? I have already answered this, but the true answer is, "not all of them at the same time." :) There are too many of them. Yes, I would put my loved ones in it. 4. Does it truly perform better than a standard system? Honestly, I don't know, but it sure seems to. Without quoting a lot of numbers, I think it does perform a little better, and I have not gotten very deep at all into the tweaking to make it even better yet. |
A good, evenly weighted writeup on your experiences Jesse.
Just a couple points: The first EFI system (Bendix) actually came out in 1956 and was fitted to some production cars in 1958 in very limited numbers so it's nearly a 60 year old concept now. The first reliable production system (the Bendix system wasn't) came out in 1967 with the Bosch D-Jetronic system. The ECU type you are using has been fitted to experimental aircraft and UAVs for over 21 years now and has accumulated over 300,000 flight hours to date and over 25 million hours in terrestrial applications. |
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Thanks! |
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thanks for the write up jesse. very helpful and very educating. look forward to hearing more about the project.
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One thing to keep in mind IF you are going to run this system: Pre-Plan your plumbing, especially the cabin. Duplex valves AND the fitting configurations, the return lines, and in the case of RV7/9's keeping everything under the stock pump cover.
Tom |
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Photo of my forward cabin area. No room in the inn for the pump in the stock configuration. ![]() |
Thanks for a great writeup. I worked on many of the 67-69 VW type III's with the early Bosch system. It had an aneroid to address altitude and no oxygen sensor. It was open loop on A/F, called manifold pressure control (speed density I think in controls parlance) It had points to trigger timed injection pulses in the base of the distributor, divided into right bank and left bank. It worked pretty well, but had an inherent "throttle on" hesitation. This would not be an issue for aircraft.
I believe all systems today are mass flow controlled systems. Edit: Sorry -all automotive. It sounds like a box of parts, instructions and you did all the map entry. Once you have all the maps filled, is there a way to save that and transfer that to your next installation? And, if so, how easy would that make the next install? Thanks for letting us know about your experience with this system. |
Jesse, that is indeed a good write-up. Thanks.
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My QB wings are arriving in August or September. I've been thinking about plumbing. Is it feasible (moderately easy) to rev the QB tanks for the return fuel line? Or does the fact that I'm going QB mean a return line will be a difficult undertaking?
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It is very easy to install a fitting in quick built tanks. Do it through the big hole where the sender goes. If you later decide to not use a return line, easy to cap off the fitting.
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Sorry to hijack the thread. Thanks of the info, Mike(s)! I'm relieved that I didn't close off a key option.
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Also on the return location, be sure it will not splash, induce air bubles in the fuel pick up area. some have located return plumbing into the next bay.
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Basic fueling is the result of RPM Fuel X MAP plus a correction for IAT. |
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EGT peaks
Jesse,
Do you find that the EGT's peak close to each other? I ask this in the understanding that in the standard injection system the fuel injected can be matched to the airflow of EACH individual cylinder. My understanding is that the EFII system injects the SAME amount of fuel to EACH cylinder, ie. not matched. Thanks. Johan |
2 cylinders peak early. Rob says that the injectors can be replaced with other injectors somehow to tune this out. I haven't looking into that yet.
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Software or hardware limitation on injector trimming?
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I would think that they might be paired, but not all injectors on one driver since they typically have a trigger amperage that drops to a hold amperage for operation. Maybe too deep, and EFII should answer. |
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Hmm. Should be able to bench check a given injector, then bench check a selection until one with more or less flow (as desired) is found. A quick spin with Google says there is a whole cottage industry out there flow matching injectors, so the services are available. |
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I've been puzzling over this for a couple days now, and reading all kinds of articles on engine operation. I'm just not really familiar with the details of piston engine operation and theory beyond the absolute basics. Props were only briefly mentioned in school, and when they were they were always turbine-powered; the only engines I ever messed with were .40-class and .049 2-cycle RC ones. |
Typically, a linear interpolation is done between map points.
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Jesse,
Thanks very much for the detailed write up. From what I know, the set up is not really as involved as you mentioned. I've seen the spreadsheet for the data points and I recall it only being 2-3 pages. Yes, it was my engine on the dyno at Barrett, and we certainly didn't get a chance to tweak anything or dial it in. It was still a good learning experience and I got to dive into the programmer. Either way, we are all headed into uncharted territory and there's bound to be a learning curve. I had previously spoken to Robert about setting up a database that we can all share our data and settings with one another and post our results. I know there's one other guy a few weeks out from being where you are and I'm right behind him. So by this summer, we should have enough data to start seeing some averages. I'll pm you directly with a bunch of specific questions. Nice work though.... Gotta love how smooth it runs. |
Is that my project?
Hey Jessie, is that my project you talk about the one with EFII, as I had that already with my RV-10. Hope that it is all positive.
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RV=12 Viking enging system
I,m installing a VikingAircraft engine (Honda) in my RV-12. Dual batteries (EarthX36) plus standby, battery for the Dual G3X touch, Dual fuel pumps, Dual EII, Dual controls and switches. Thanks for your report.
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There are 64 MAP points. Using a 1 Bar MAP sensor for naturally aspirated engines gives you about 0.5 inch increments. There is MAP averaging to calm down any scatter. There are enough small variables that LOP operation should probably be set via the mixture control using either EGT or the wideband. You could cross the rpm and MAP points under other conditions where you might not want to be LOP. Injectors are batch fired, usually in pairs depending on the system. They are not timed to valve events with this system. OTS injectors are usually flow matched to about 2-3% variance. Along with this, each port flows slightly different amounts of air so this results in the same issues as with mechanical injectors hence the GAMI idea is needed to correct AFRs for individual cylinder. Some very high end EFI systems allow you to individually trim each injector pulse but they are very expensive and you can imagine how long this might take to program. |
joining the EFII conversation...
... I don't have anything to add to the discussion at this point, but rather throwing my name in with EFII crowd. What I have installed to date:
-RV-8, Titan IOX-360, horizontal induction -EFII dual electronic ignitions, dual ECU installed -EFII bus manager installed -EFII electric fuel pump and traditional engine driven mechanical fuel pump -my fuel pump system is NOT EFII electronically controlled system -single alternator, dual PC680 battery -Silverhawk EXP injector servo I have above installed, but no where near engine start. I will add this one point... if you are contemplating this system and using EFII bus manager, plan electrical system early. I had electrical mostly complete before I made the decision to instal the bus manager. The bus manager looks like a great piece of gear and would have simplified installation had I started with it initially. |
Chris Golden has the plane now and will be working through all of the fine tuning of the ECU's.
Noted thus far is that the GAMI spread is about 1.4gph, so hopefully he can get those things worked out. Robert said there is interpolation between rpm settings, but in our testing there was none, which agrees with what rv6ejguy said. It is a smooth running engine, but it will be even better if we can get that GAMi spread tightened up. |
I recently finished my Phase 1 in an RV7 running dual EFII injection and ignition on a Titan IOX-370. A couple of points:
Do not think that the engine will run anywhere NEAR its capabilities with the stock EFII setup. Unfortunately, you will have to do numerous engine runs before the first flight getting it in the ball park. This stinks for a new engine, but at least the Titan has a 3 hour dyno run at the factory, so much of the break in is completed there. You have to program each ECU individually. In order to do this, you have to unplug the programmer from one ECU and into the other. This is a bit of a pain. At some point you will have to start tweaking the programming in flight to get it so the fuel mixture knob is basically hands off in flight pointed at the 12 oclock position keeping all the temps in tolerance. If you have an O2 sensor, this is much easier. Once adjusted properly, you should only have to touch it to run LOP. Adjust your ECU 88 in flight (it is the one that should be controlling the fuel injection curve), land, write down the new settings, then plug in the programmer to 71 and make it match the 88 numbers. There is NO information on Robert's website on how to adjust all this stuff. However, his system comes from http://www.sdsefi.com/ (Simple Digital Systems EFI). Go to their website for a TON of info on what all the settings do. Strangely enough, my engine also starts easier while hot than cold. It also runs smoother than any other aircraft engine I have heard, and idles really low. My engine sounds like a car! My GAMI spread at higher power settings (75%) is 1 gal, however if I go LOP at lower power settings (50%) I am at .3 gal. In trying to decrease my GAMI spread at high power settings, I swapped around injectors to see if that would change the cylinders that peaked first/last and it did not do anything. Thus, all my injectors are flowing the same. There is no way to adjust that save making your own circuit for each injector to try to adjust the dwell time. My understanding is Robert does not have different sized injectors available. However, maybe they are available somewhere. Haven't looked into it yet. I get anywhere between 4-8 GPH fuel burn when running LOP based on my MP. I am at 16.5 GPH WOT ROP. Also, when running LOP, my last cylinder to peak is usually about 90-120 deg LOP and the first will be close to 200 deg LOP. Still runs great! It takes a lot of leaning to get it to run rough. The return line is not that big a deal. I added an AN6 firewall fitting to the fuel tank access plate right next to the supply line. However, don't forget, you have to buy the Andair valve which is expensive! About $500. The biggest thing I hope people understand, is this IS NOT a plug and play system. You will have to do a lot of tweaking! However, once done, there is not a better system on the market! Feel free to PM me with questions. |
Thanks for the real world reviews guys. This system has been given a fair bit of press in recent times and promoted by a few engine builders, particularly Titan Engines. The tuning you describe is nothing like some of the other FADEC products (Aerosance comes to mind).
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EFII Map and Tuning
EFII MAP and tuning :
Aloha all, FWIW I?ve got over 185+ hours on the full dual efii system fuel/ign on my -7 IO360 Mattituck Jesse did a good job on relaying his experience with the EFII. I?ve got to agree you?ll need to do some work to get the fuel map right on out of the box. If you read and follow these instructions from the SDS site you can map it quickly: http://www.sdsefi.com/EM5%20MANUAL.pdf page 21- the wide band O2 data (AFR) logging is a good way to get the most out of the system, very easy way to fine tune the AFR quickly. I?ll do the ground runs and try and set the fuel RPM #?s to give me 12.0 (make sure engine temp is warmed up prior to making adjustments as you don?t want the START or Engine TEMP tables to be in play) then fly the plane and see what the data log has in it at the different fuel rpm?s. You?ll need to make a fuel RPM sheet to write down what you have current and what you add or subtract from the Fuel RPM # that you want to change. I use the mixture knob to add or subtract fuel % real quick and write that change % down on the fuel rpm # I?m adjusting (you can see the % change on the programmer Gauge2 _knob) don?t forget the re zero the mixture knob before you go on to the next fuel rpm # or you?ll skew all the fuel rpm numbers that % of change. Once you have the map built you don?t have to play with the mixture knob at all. You can use the Mixture knob to run LOP or ROP to you want to play with it in flight. Just remember to add it to the Takeoff and landing checklist to make sure its centered up My 2cents Lee |
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This is a user programmable system so it's not like an OEM engineered and programmed system like Powerlink or IE2 which is fitted and programmed to specific engines. It's also different from aftermarket aviation solutions like the Eagle EMS which is around $11K. The idea is to give users in Experimental Aviation many of the benefits offered by expensive, factory developed FADECs at a fraction of the price. One of the challenges in programming for a wide variety of experimental engines is the variety of displacements, induction, porting , cam and exhaust system differences. The OEM systems only have to work on one engine configuration and their engineers can spend many hours mapping to that end. This article may be helpful for some people to better understand the system: http://www.sdsefi.com/aircrafttuninglyc.htm Information sharing and feedback from users is helping to shape future improvements and developments and hopefully improve initial setups for different engine configurations. Also, just coming available now is 8 channel data logging to PC capability to further assist in mapping the system. |
EFII info
Here are some general notes just to clarify some of the things discussed:
1. The beauty of electronic fuel injection is that you get the same fuel to all cylinders (balanced delivery) under all operating conditions from starting to full power. This is not possible with any other type of fuel delivery. The benefits of this are very noticeable when operating your engine. You also have a very easy way to tune the fuel delivery at different operating points - also a huge benefit. 2. GAMI spreads are a method to attempt to balance mechanical fuel injection systems. This technique does not take into account that fact that you may have (probably do have) imbalanced air flow to the cylinders as well. GAMI spread information is not applicable to electronic injection - you already have balanced fuel delivery. The GAMI spread that is witnessed with electronic injection is not an indication of unbalanced fuel delivery, it is an indication of the air delivery imbalance. I have had customers suggest that they want to unbalance the injector flow to lessen the GAMI spread - don't do this. This is working against tuning balance. Fixing the air flow imbalance has no simple solution. Unless you are going to engage in an engine designing exercise, you are stuck with the air flow balance or imbalance that you have. The best that can be done is to have balanced fuel delivery and a high energy ignition to ensure complete combustion even if there is an air/fuel ratio variance between cylinders. This is exactly what the EFII system does. This will give you the best power balance between cylinders and the smoothest, most efficient engine. 3. EFII tuning. There are only five numbers to tune to dial in the fuel delivery of your engine when it is making cruise to high power levels. This can be done in a few minutes with minimal experience with the EFII system. Simply use the tuning knob to find out what percentage change you need to the fuel delivery to get an air/fuel ratio of 13:1, change the fuel delivery number by that percentage and you have it. This is done in 250 rpm increments. The ECU will handle figuring out the delivery between those data points. We try to go over all the ECU values with each customer before they tune their engine so that they know where the numbers are, and how to change them. Once you do this once, the mystery rapidly fades away. 4. Flying. Once you have a basic tune up, you don't have to touch anything to fly. The ECU will handle the entire fuel delivery task. After you have a little familiarity with the system, you can reduce the fuel numbers at cruise rpms to automatically lean. You can also go a little bit richer (12.5:1) at max power rpms. Yes, there are some new things to become familiar with. Yes, there are some big advantages to having the ability to tune your engine from the cockpit. We have customers from a wide variety of educational backgrounds with a wide variety of mechanical skills. I am always amazed at how well the vast majority of customers get up to speed quickly and painlessly. It is great to see them get to enjoy all the advantages of their "modern" aircraft engine. Robert |
Of course Robert is right on point. Just to clarify though, in order to get your air/fuel ratio data, you must have an oxygen sensor installed. The EFII manual recommends it, but if you are going to have any chance of getting this programmed correctly, you MUST have an O2 sensor.
Now, I do not have an O2 sensor installed, YET! Luckily, I have a neighbor that has been running a similar engine with the EFII for years. Thus, I was able to take his programming and enter it into mine. Without his help, there was no way I could have gotten it running smoothly. My next aircraft parts purchase is going to be an O2 sensor so I can fine tune my system. So, the bottom line, if you're gonna install EFII, also plan on putting in an O2 sensor. Again, I am a firm believer, there is not a better injection and ignition system on the market today. You must understand however, this is not a plug and play system! |
BTW, Robert at EFII has been a ton of help. Great customer service! Thanks!
A small recommendation though, you have a lot of accessory parts available that are not listed on your website, such as the fuel flow box and throttle body adapter. It would be helpful if you listed all the accessories on your site. Also, a programming manual would be useful. |
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