It is an interesting question. I invested no less than ten years towards the conversion of Subaru engines for aircraft use and have followed the movement closely for about fifteen years. In my opinion, I was successful – more on this later. Why are we not seeing Subaru Aircraft Engines at fly-ins and magazines? Where have they gone? Why are there not several companies offering their own conversion packages and making gobs of money while pulling aviation into the modern era with better, cleaner, more efficient, less expensive engines?
In my opinion… hey! This my blog – I don’t have to say that do I?!?! There are a bunch of factors at work.
There is no evangelist for Subaru Aircraft Engines or the conversions of them. Nobody is standing up and preaching to the masses about the benefits of the Subaru engine. There have been a few that some would label as such (but I disagree). Jan Eggenfellner comes to mind. He was a stake holder and evangelist. He drove the Subaru conversion world, he marketed, he preached, he convinced people. Sadly, he didn’t test, validate, or evolve his products – he simply walked away with hundreds of “believers” holding ten of thousands of dollars of “junk” (arguably) when he realized what a huge mess he had created and that fixing it would take a massive pile of money. He did aviation and specifically the Subaru world a terrible disservice. He was not the first nor will he be the last. His former customers have been unbelievably kind in not tearing him apart in court and in the press – amazing to me. To those that are “Viking Aircraft Engine” customers – don’t start crying when the same thing happens to you. There is plenty of history there for you to have made a better and different choice. I guess the saying is true: “We learn from experience that man does not learn from experience.”
Very few people want to actually “construct” something in the sense necessary to convert an auto engine for use on an aircraft. Many like to assemble parts assuming it requires as little thinking and labor as possible. Look at the numbers of people “constructing” a Van’s RV versus the number currently constructing Long-EZ’s or similar. Is a Long-EZ a “poor” airplane? Of course not. It simply requires a great deal of work to construct (compared to an RV). The amount of “construction” (design, effort, head scratching, build a prototype part, throw it away, build another, etc…) that is required when creating an automotive engine conversion is massive when compared to what is required to bolt on an firewall forward package. It is worth noting that I have nothing against RV’s – I fly one and love it. I believe the success of Van’s has been good for all of experimental aviation (sport aviation, if you must).
Very few people want to spend big bucks on something “experimental.” Buying a Lycoming, Continental, or Rotax (912-style) is a relatively known quantity. You may be forking out $25,000 – $50,000 but you know what you are getting and know that it works because of their documented track record. Thanks to businessmen such as those mentioned above and the non-existent track record of any “new” package – laying out this kind of cash is pretty tough for most everyone. Anyone that has been around experimental aviation for any length of time has seen the snake oil salesmen come and go taking the money of the young, unsuspecting, gullible, hopeful, and/or stupid with them.
With any unknown, getting insurance for it can be rather difficult and/or expensive. Some folks don’t care about this. Some do. I’ve personally watched ten years of hard labor burn to the ground in front of the builders eyes in a matter of five minutes – no insurance – a total loss – nothing but pictures to show for the many, many hours and thousands of dollars. No, a check does not replace the blood, sweat, and tears but it does help.
The emphasis of most general aviation aircraft is on lightness. A “properly” converted Soob is not light. It may not be any heavier than a Lycoming or Continental but that should not be confused with light.
The Subaru presents a couple of challenges that are very difficult, if not impossible, for a small company to overcome.
- It is a small displacement, high revving engine so it requires a Propeller Speed Reduction Unit (PSRU, gearbox, reduction drive, etc…). This requires engineering, precision manufacturing, loads of hours to prove in the test cell, and then many hours/years of flight time to create a track record that customers believe and can trust. To date, those who have tried have failed. There are a few PSRU manufacturers around but not many and finding people with thousands of hours behind the units is very near rare/difficult. If you do find one, find out how much he has had to work on/modify the PSRU – I’ll bet it’s a lot.
- The uneducated believe that the automotive fuel injection and ignition control will work in an aircraft. This is a nice thought but proven to be wrong. With the early units, it was possible. Time has proven that this is a bad plan and current EFI systems are becoming more and more complex making them less and less appropriate for aviation use. However; there are a couple of very good aftermarket EFI units available. Some believe that strapping a carburetor on is the “smart” approach. If running normally aspirated and one doesn’t care about any of the advantages of EFI, a carb works. It is far from a good solution though if one is trying to truly take advantage of all that a Subaru engine offers. Ya, people fight about this all the time – people once that horses were superior to automobiles for transportation. For those in this camp; get over it and join the modern era – do some research and try to learn something.
- The more recent engines are adding much complexity that is simply not desired in an aircraft engine. Variable valve timing is an example. Eliminating these types of things is no simple task and may (probably) significantly alter the highly reliable nature of the engine.
- It is well understood that one can get these engines to produce a great deal of torque and/or work well for us at altitude with a turbocharger. Yes, indeed. However; most people do not understand how to properly size a turbocharger for aircraft use nor do they understand that an intercooler is mandatory or that electronic fuel injection and timing control is also required for reliability. Once you get past all that, you must have an in-flight adjustable propeller to properly use the power that is now available to you at altitude. Guess how much all of this cost you? Not just in terms of dollars but also complexity, reliability, weight, and maintenance.
Why are there no companies offering Subaru Aircraft Engines and conversion kits? Because no market exists. Without a market they cannot sell enough products to make money. Without money they cannot stay in business. Yes, this makes me sad but it is the free enterprise system that I support and defend even though it is largely lost at this point.
So, we are left with dozens of one off installations. That is, every installation is a hand built package that is different than every other. One cannot compare cost, output, reliability nor any other factors because they are all different. The new guys comes along and wants instructions, instead they receive a thousand different ideas. They are confused, frustrated, and annoyed. They return to the Van’s catalog engine page and select the firewall forward package that is fully documented and proven. They write a check, turn a couple of bolts, and go flying.
Back to my comment about being successful. To measure success, one must know the goal. My goal was to fly inexpensively with as little financial investment as possible. To me, this meant that I needed to buy an engine, convert it for aircraft use, and install it for little money. After installed, it needed to be affordable to feed and maintain. I flew two Subaru engines in my Quickie Q2. Neither of them cost much money (relative to other engines used in general aviation). Both of them burnt a relatively small amount of fuel and were inexpensive to maintain. Without getting into exact dollars, I judge the experience a success. I had piles of information on my old website but that is gone now. I flew each of these engines something around six hundred hours (from memory, I’m not going to go dig out the information). I spent VOLUMES of time converting and getting these engines to work. I enjoyed this “building” time, for the most part – I’m not sure my family enjoyed it though. I’d ask but none of them are around any longer.
Very good article Jon,
I’m going to post a link on Rotary Wing forum for my ‘friends’ to mull – you probably know some people on that site.
To me, the Soob conversion for aircraft embodies the true sense of the phrase ‘experimental aircraft’. I am building an autogyro and picked up a 2.2 with VERY low miles for a song (not my singing!). As of now I am enjoying the engineering and learning as I go, probably as much or perhaps more than flying. Having 10+ (expired)hours toward PP-FW, I stopped because it was boring me to tears.
And if my ‘one-of’, home-built, self-engineered PSRU works well after 40 hours of testing, I’ll most certainly post info and a wealth of data on the web for all to criticize, bombast, ridicule, etc. etc. – but it will be my ‘experiment’.
Thanks for the post.
Chris
That would be awesome Chris! Best of luck on your project and stay after it. Sometimes it may feel like you are taking more steps back than forward but you’ll get thru it and love the result – especially since it is of your own creation!
I was dumb enough to buy and fly one of Jan’s engines. In about 40 hrs the $10,000.00 MT prop fell off and I ended up walking home. I only has about 6,500 hrs in various planes and Jan explained the problem (shaft fracture and separation just aft of the prop flange) was that I was not an experienced pilot. I didn’t strangle or sue him. I just trashed the engine in a dump an mounted a Lycoming.
time you buy a new block and heads 2k machine work rotating assembly and small parts 5k psru fuel and computer work 10k at least 5k in mounting and miss.parts haw much more would certified motor cost and o keep the same wife/girlfriend
Jon, thanks for a great response,as I totally agree with everything you mentioned and that is why I will attempt to power my slow build rv4 with a direct drive recamed 2.5 ,otherwise as stock as possible.I am firmly convinced that people think they are smarter than the OEM people are wasting their time.I will use everything that my2.5 was designed for.I think most of us are il prepared to remove varioable valve timing at this time.
Tom Hankamp
Jan Eggenfellner may have had a good idea but when he took money and failed to deliver props and hardware, he turned into a crook.
He is now selling Honda packages, after having stole hundreds of thousands of dollars from his original customers. I purchased one of his conversions from two friends who he ripped off. I am returning it to use as a vehicle motor in a sand rail.
Jan is lucky that someone hasn’t taken him out for what he did.
My friends are out over $ 40,000.
I enjoyed your article.My father and i have built a RV 9-A, and did not want a Lycoming engine. we wanted a affordable engine. And decided on a Subaru EJ 25. we kept it as original as possible but had to modify the oil pan and cooling system, fuel system. It was a challenge for us and at times frustrating trying to find help in our project. but now we have over 100 hours on it and have very much enjoyed the plane. the low fuel burn is great, and we can afford to fly. We may find additional bugs to work out but, that is why we built an experimental. To other builders we would like to say keep the faith and you will have success. If we could do it, you can!!!
Thanks Ken. I agree – it is most certainly possible and the Soob is a great little engine!
Hi! has i see you know a lot about Subaru engine ,so the point i want to know ? is if it’s possible to make the engine Subaru 2.5 rotate in backward (inverted) you know what i mean ? and if it’s possible can you explain to me how we do that? It would be very very kind and useful for me .
I think it’s possible because sometimes aircraft with twin engine has to have it in the opposite rotation, right?
Hi Steve, I think it would be possible with a set of camshafts that are ground correctly (sort of reversing the intake and exhaust valve timing) and a modified EFI system that squirts and sparks at the right time. I’m not smart enough to know if there are design issues that make this a bad idea (such as stresses on the rods and pistons).
Hi forgive me my comment/question was for Steve.
Also to add to what I was saying, there are alot of race parts made for these Subaru engines, like dry sump scavenging pumps, oil cooler,injectors (different flow rates), light weight connecting rods, high durability pistons, crankcase bolts and studs and aftermarket efi tuning hardware and software. For me personally and from what I’ve reade here it makes sense to pursue. My last 2 cents.
Regards Jonathan
Hi JD, I really like what you had to say about your conversion engineering experience and would like it very much if you could give me a few pointers as to what you changed and why. Keeping cost down in aviation will grow interest if it can be done safely and I personally think the Subaru power plant lends itself well to aircraft use. I have to agree with you on the licoming though, lol. Any pointers would be appreciated
Regards Jonathan
Hi, Mr. Finley.
I like your site, very informative in every sense. I am a new pilot (only 100+ hours) and have good skills in mechanics and electronics. Like you, I chose EJ22 to make my homebuilt.
One thing I noticed is, did you have to reprogram new codes into the ECU for fuel mixture at high altitudes ?
Thanks a lot and keep up the good job. Apparently you are the one who will open the market after time-rating your machine for life cycle of all components !
Marco
Thanks Marco! I initially used the stock Subaru ECU. This worked but I was not happy with the inability to tune it. I then switched to the Real World Solutions EC2 controller which is programmable. I loved that unit and spent a lot of timing tuning it.
JD
Your conclusion of “no market exists for Subaru” is wrong. The proper conclusion is the Subaru does not
make a reliable, trustworthy, aircraft powerplant and has higher fuel consumption and failure rates
than traditional aircraft engines. Ask anybody operating one how many engine-outs or failures they
have had. How many overheats, how many gearbox changes. Experimentation is fine, but this engine
option has progressed past investigation and experimentation, and has decidedly become a non-player
if you want a safe, reliable and efficient airplane powerplant.
I have owned two avid flyers with ea81 and got over 1800 2500 hrs of great flying be for tearing them down.
For lighter planes I would suggest the stratus ea81 . Good luck all, great little engines.
i have a subaru engine that i want to use as a aircraft engine i am interested in going direct drive do you have any plans for sale that i can get
thanks for any help
ted
Hi Ted – Sorry, I do not have plans.
do you know anyone that might have plans
ted
No, sorry. Don Parham used to have a book but I think it is long gone and certainly doesn’t apply to the newer, more complex engines (unless it has been updated). It really is a DIY project.
What I really need is the specs for the prop mount and flywheel
do you have the specs on the propeller mounting hub and flywheel
I’ve moved what I have from my Finleyweb.net site to the Drawings page on this site.
Very nice article, Jon. I’ve been following the Egg story for several years. It’s so unfortunate that Jan didn’t take a better approach to testing and supporting his product, much less delivering what was paid for. He seems to be a gifted engineer and attention to detail on his engines was pretty impressive. They sure LOOKED like beautifully-crafted engines. I’m curious what people think of the latest versions of his engine with the Gen 3 gearbox. Did he finally nail the design, albeit too late? In other words, is this an engine and PSRU you could buy, install, and fly behind without having to keep tweaking or otherwise re-engineering things? I’m curious, because I’ve seen brand new ones being sold cheaply. I’m assuming most of these sellers were nervous about either the reliability or the future lack of support or parts availability from Eggenfellner. I’ve noticed his old site it long gone. It’s just Viking engines now, with no mention of Subaru anymore. He truly ran away from it. Any opinions on buying a firewall-forward Gen 3 Eggenfellner engine package (for less than $10K)? By the way, it’s interesting to note the similarity with the Mazda rotary engine world. No firewall forward engine packages, and very few PSRU makers still active.
Thanks Jarod! Based only on the information that I heard from the owners of the later model Egg engines, I would stay away from them. These were the engines in which the internals were modified. I believe at least one of them failed due to the poorly made modifications to the variable valve timing system. The SDS EFI system that came on some of these engine is an excellent system. The problem is that it was never properly tuned (and that was Egg’s responsibility, not SDS’s). I’ve heard that the Gen 3 was an improvement but I think most everyone had quit flying them by that point so I suspect very little fleet time was ever put on them – meaning they are unproven, in my opinion. If you are a real experimenter, have an airframe that has superb engine out/off field capabilities, have another airplane to actually fly (if that is a goal), don’t mind tinkering for the next 5-6 years, and don’t mind throwing it all away in the end, the Egg engine might be an acceptable starting point. If it were me, I would stay away from them. (my apologies to the guys that are trying to unload these FWF packages)
Jarod, I have about 750 on a 2.5 Egg engine with the Gen III in an RV-7A. It is a great engine in cool or cold weather but does not have the climb performance in the hot summer months. It will not give you the same cruise/climb performance of a L-o320. I would estimate that you loose 15-20 horsepower going through the PSRU. It is nice to burn regular fuel but the ethanol has made it much more difficult to find fuel. I have saved enough on fuel to pay for the engine but would not do it again because of the problems finding fuel now.
Hi, Neil. I just now saw your message. That’s helpful info. Thanks! So, is it a no-no to run the Subaru on ethanol? I’m in California, so I would be in the same boat. It’s all ethanol gas here. Anyway, I’m not in the market for the E6 Subarus at the moment. I may be considering a Pulsar SP100 though, which would probably fly nicely with a 4-cylinder soob, around 130hp. I’m not really looking for an engine package that I’ll need to keep tinkering with, though, so Subaru may be out of the question entirely. The ULPower UL350is is very enticing, although expensive. Thanks again, Neil, and thanks Jon for the forum and great info.
I bought an SLSA with the RAM 115A EFI Subaru in it two years ago and I am still not comfortable with a long cross country. Cooling issues and rough running while transitioning from dual to single fuel pump seem to be the biggest hurdles. I love the engine but will I ever get to stretch it wings? Any suggestions would be greatly appreciated.
I’m flying a Kitfox with a Subaru Engine.The Engine has now about 850 hours on the Tach and I fly it over the Swiss Alps sience more then 15 Years.Until now,I didn’t have to many Problems with it.
…traditional general aviation motors are outdated garbage.
Had a similar mindset prevailed in the automotive world, we’d all still be in Model T’s.
“It was good enough for our grandfathers” is a terrible justification to still use these dinosaurs as aeromotive power. We tired of seeing the same outdated garbage from Cessna, Piper and Beech and set about building newer exciting designs….. where is the same spirit with respect to motors?
Grumble all you wish about motors designed after 1930, but modern Subaru motors are quite amazing little things that are not only reliable, but economical as well.
Too bad for the Luddites; but not everyone sees “not having to worry about carb ice” and “not having to fiddle with leaning” as “selling out”. Keep your antediluvian Lycomings and Continentals; if we wanted something that looks and sounds like the dog’s breakfast, we’ll get a Briggs & Stratton….
This is preaching to the choir. The parasites in the trial law biz, the insurance extortion racket & the revenooers in OKC strangled innovation for generations.
I have an EA81 setup with a gearbox PSRU that works like a charm with some 125 hours on it. The EA81 has Subaru fuel injected heads and with the timing wheel on the pulley it also has the Subaru electronic ignition system. ECU is a Link Storm 4 made here in NZ and I have tuned it up using that setup, tuning is completely different from a car’s setup, it has a sensor that allows for altitude variations so no problems about mixture settings at altitude. Burn is at 13.5L/hr and the engine is great, starting first time and running smoothly with a 70″dia 3 bladed Bolly prop. Happy to fly over the mountains near my place up to 10,000 ft.
I am building a Murphy Rebel and I would like to put a Subaru in it .I see you live in New Zealand ,could I have your ph no so we can have a talk about it
Funny did a search of Subaru motors and airplanes after listening to a car talk episode where a guy asks that very question. nice to see a discussion about it. I think I would trust a Subaru 2.2 motor in the sky any day.I believe this may be the greatest motor ever made and am very interested in using it just for purposes on the ground. But myself always wanting to be a pilot maybe someday I will venture into the sky with one. Thank you for the article
Jan devoted 15 years of his life trying to adapt the Subaru to reliable aircraft use. Rather than
question his motives or his ethics, let’s consider for a moment that the auto engine works
best in the platform it was designed for, an AUTOMOBILE. The complexity of an auto engine
is primarily to satisfy emission standards, and to take that complexity into the air represents
an unacceptable risk. PSRU’s have always been troublesome, and are unnecessary if an aero
engine is used.
Yes, some ideas are not worth pursuing. I think Jan did his best, but in the end, discovered that
he was facing insurmountable problems.
John – your comments sound good until one understands that Jan left many of his customers high and dry and IMMEDIATELY started a new company doing EXACTLY the same thing (converting auto engines for aircraft use) to a whole new set of customers.
Rotax engines use PSRU. All of them.
Couple of thoughts to the comments above.
Firstly PSRUs have been used for years and like anything if done properly and maintained they work like a charm, witness the original Hipsano Suiza motors used in WW I in the SE 5a fighter et al, a solid V8 configuration that was later used cars. One of the all time favourites the Merlin, either RR or Packard, also had/has a gearbox PSRU up front and in modern day terms the Rotax engine does too.
Secondly, with Subaru engines all you need to do is get rid of all of the smog control stuff and make sure that the clearances for the engine bearings are at their upper end so that you get lots of good cooling oil passing through them, just like VW used to do with their air cooled flat fours. Install a custom ECU that can control all of the ignition and injection and there it is. In my case the only thing that is Subaru EA81 is the block and heads, the rest is custom. Keep it simple.
Hi Jon,
Long time no hear!
I’ve experimented a LOT with my EJ-25 powered Jodel to the point where I now have a completely reliable, very powerful and very smooth engine package. I’ve got some 400 hours on it now and it has never missed a beat. Takeoff performance is out of this world (2500 fpm climb rate), with the engine sipping fuel at 5.5 gph in cruise. Maintenance is just changing oil every 50 hours. Cooling is spot on – I can idle the engine on the ground indefinitely, even on the hottest days, and then blast up to FL95 with the temp gauge never leaving the 185F mark.
So indeed, like you said, it CAN be done. And I am very very happy with how the whole thing turned out. Like with you, it did add quite a number of hours to the project though… 🙂
Hi Hans! That is an awesome report! Very well done!
Sir, would there be any way to obtain the information on your build if it’s at all possible ?
Hi Rob. I’m afraid you just missed it. I used to have all the details on finleyweb.net but I shut that site down a few weeks ago.
Jon what psru did you use if any?
None – direct-drive.
This has been a very interesting discussion. I am thinking about buying a Kitfox Vixen that has a new Subaru E81 fuel injected, turbo charged 130hp engine swinging a warp drive in flight prop. This was purchased from NSI. Is this a good setup. The engine was purchased a while ago and has only run for about .5 hrs. I am a little reluctant to purchase this plane with NSI not still in business. I read more bad than I do good about these Subaru conversions. Can anybody help me?
Don’t buy it, check in to the stratus convertions. nsi was a bad deal and no more support.
Stratus is still operational.
Mr Finley, I have been following your Subaru saga for years – VERY INFORMATIVE! I just wanted to take this opportunity to Thank you for sharing your experience on the web with us all. I have learned much and am using many of your lessons to put to use on my EJ22 installation. TTHHAANNKK YYOOUU AGAIN¡
this guys do it successfully many years http://dvsubaru.ru/
I was wondering where we could get a set up. I have an EJ 2.0 turbo in my off road car. Has a link ECU puts out 330 hp. and never a hick up or burp fircken screams.
I have a 92 legacy L 130hp engine that I may try to convert for an excremental plane design I have just thought of. My engine already has ~200,000 miles and wondering how long these engine last and do you do a overhaul for these engines and last, do the engines give good sings of failures so the engine does not break down while flying(my biggest concern, though I have not had one engine problem with it)?
I have’t heard anything about the Subaru 160 hp
Very many out there?
Hy
I am new to making comment’s I have watched the homebuilders for the last 20 yr. seen things that made me shake my head! First comment Almost all automotive engines are not made to turn 4500-6000Rpm. under continue full load. strike one, choose a psru that will give you 4500 clim 35-3800 cruse.
If you can find the video of Eggenfeler assembling his re -drive, note the cuttings O” MY! All engine must have cooling jets under the pistons, I could go on, George
Hello all,
I have a Dave Johnson Subaru EA81 PSRU firewall forward package ready for mounting c/w motor mount for my Bushcaddy R120 I purchased a Warp drive 3 blade 72″ R prop and pitched to 13* at tip
I flew 42 hrs. but felt that the performance was poor.
I adjusted the vales and timing to subaru specs and added a vacuum advace hose from the distributor to the intake manifold but my performance is worse than before. (manifold pressure drops to 0 at 4200 RPM now ) I was told not to go under 3
I was never given instructions for proper set-up with the different cam from California installed in the engine by Dave.
Any insight out there?
Warren K
Warren, if the engine had a modified (reground) cam it should have been setup for optimum torque circa 4,0004,500 rpm with 4,000 the sweetspot for cruising with mine. Generally if running engines at for long periods you want to keep the piston speed below 9.8 m/s, you only get there on the EA81 when at 4,200 rpm which is my high speed cruise.
You do not need the connection to the vacumm, disconnect it as it is a waste of time. It is only needed on road engines for sudden acceleration to stop knocking, not an issue here.
In terms of prop size I have had mine modified from 70″ to 68″ dia so that I could get 4,600 rpm on take off and 5,000 rpm at full throttle in the air. This gives me good take off and climb performance, 1,200+ fpm 1 up as well as a good cruise speed of 90 knots at 4,000 rpm. Fuel consumption has gone up to 14 L per hour but distance covered has improved so there is a net gain. Flew 2.8 hours over the mountains to Auckland and used only 38 L of fuel.
There are web sites that have calculators on them to work out prop speed to hp and pitch so check them out to get your pitch setup right, although it is always very suck it and see aircraft specific.
Good luck, Trevor
Trevor, Thanks for the detailed info. I will help me zero in adjustments on my airplane.
One more thing, What would be the optimum setting BTDC timing for this engine?
Warren
Trevor – did you do your own conversion? I’m scoping out a Subaru repower for a BD4.
Hi Terry, yes and no is the answer! When I bought my aircraft it had been converted and was running carbs (twin bing) and a normal distributor with hall effect switching for points.
Some 20hrs into flying it I experienced a prop strike so had to get the PSRU and engine checked out. No problems with the formaer but the latter had some crankcase bearing issues so I had it completely rebuilt with new crankcase, bearings etc and that is when I undertook the mods – had an engineering shop do all of the key stuff for me to end up with the rebuilt shorblick engine and then did the rest myself. Was quite a learning curve I can tell you but I got it to where I want it and now I know the engine inside out and trust it implicitly.
One thing if you are going the fuel injection route, you cannot use the standard car map to control timing and mixture against MAP.
For an aircraft the mixture/load curve is virtually linear and you want to have the mixture rich for power and climb, stoich for cruise and then lean when you are throttled off and descending. Mine works fine like that keeping all temp parameters under control even on hot days, and we do have hot days of 30C at 2,000ft!
Hope that this is of some help to you.
Regards Trevor
Hi Warren, I tried a number of settings, that is the beauty of having a programmable CPU and found that 33 deg max at 2,000 rpm worked well for me. Any further advanced did not give me any improvements on hp, fuel consumption or running, if anything it could have ‘over cooked’ the engine and stressed it too much. Given I am a cautious person this did not seem to be a good idea.
This setting fits nicely into the EA81 specs so that’s good too.
Anything less than that would see a loss in power.
Hope that helps
Regards Trevor
I was wondering where we could get a set up. I have an EJ 2.0 turbo in my off road car. Has a link ECU puts out 230 hp. and never a hick up or burp fircken screams.
look up this link https://www.outfrontmotorsports.com/subaru-jdm-motors/
John at outfront mtr sports can do anything it’s not uncommon for 2.5 to get 400 to 500 hp.
they sell ECUs for all subies so no smog issues just raw power.
Trevor,
I recently purchased a zenith 701 with EA-81, Stratus redrive, modified cam, shaved head. I don’ have any documentation on this redrive, ignition, etc. Is there timing marks somewhere on the stratus unit?
Great post! Have nice day ! 🙂
Hello everyone
I have a Subaru EA81 engine on my aircraft. I’ve been flying for 180 hours with no problems. But I would like to increase his power. Now it’s only 80 HP. Is this achieved with a different camshaft? Can anyone advise me on this? Where can I buy such a shaft?
You may be able to find some Delta cams for this engine floating around on subaru enthusiast sites. They used to grind factory blanks, but I dont know if they are in business anymore.
As it is NA, a good porting and larger valves may help.
The final option is forced induction, but the increased complexity doens’t seem to lend itself to aviation use.
Hi Jose, not sure if you have sorted your question but before saying anything I think that letting us know what your engines operating parameters are, e.g. what aircraft is it mounted in, what type of propeller are you using, is it geared/belted to get the prop speed down, what is the ignition system, what types of carbs do you have and finally the exhaust setup.
All of these influence what it is that you are trying to do and yes Mike is correct in saying that another cam profile could work, but it depends on what rev range you are operating in.
if you still would like some suggestions just let us know and I can give you some of my experiences with this, having played with just about all of the these in my quest for power and reliability 🙂
Hello Mike
I already wrote on Delta cams.
But what is NA?
NA = Normally Aspirated
i have a Stratus 2000 EA 81 Subaru with belted PSRU built into my Bushbaby. Airfield elevation is 5300ft asl and on a cool morning we have seen climb rates of 1200 fpm. Engine now on 126 hours.
One problem is that we experiece some belt flap when power gets pulled (off) and engine goes throug a specific rev range (very briefly) and then smoothens out again. Have tightened belt tention but you can still see belt flap when dropping revs suddenly. Running 2 htd belts on the standard Stratus PSRU 2.2:1 ratio. Over tensioning causes whining noise.
Any advice please
Hi Deon, have not had this experience with belts on a psru as I have a geared unit. However in my farming days i did have a big fan unit driven off the PTO of my tractor which was used to suck the leaves off for leaf plucking.
3 big belts were used to get the speed ratio right and there was the same problem.
This was overcome by putting a spring loaded idler wheel set on it which controlled problems like that, i.e. belt flapping due to throttle changes. My vineyard mulched had a similar setup.
There must be something on the net somewhere about it or at the very least visit a farm equipment place that could have some examples of this.
Hope that helps.
Trevor
Hi all.
My name is Geoff Braddock and I have engineered my own 2.5 litre turbo charged engine package for my Vans RV8.
It has 186 hours on it so far with no problems to speak of. I designed and engineered my own under wing radiator installation which totally solved the issues of cooling this type of installation. I use MoTeC engine management specifically tailored for this application, an inline water cooled oil cooler( so the rads also cool the oil) and a very compact turbo intercooler. I am using the stock turbo(yes I can hear the experts all grumbling) and have had no issues and regularly fly at 12-15000 ft. I fly in temps ranging from 35+deg Celcius in summer and 0 deg celcius in winter.
I use an AUTO Flight H6 300 PSRU @ 1.95 : 1 turning an IVO Prop 76 inch Magnum in flight adjustable prop. Prop rotation is LH tractor. I had an amazing time building this installation and would happily do it again!!! I am not anti the established aircraft power plants but love doing things my way as I believe that we need to move on and innovate.
Cheers
Geoff
Sounds like a good Geoff! Well done!
Hello Geoff,
I’m considering an Project RV-9 with 2.5 Ltr Supercharged Eggenfellner Subaru Engine. (aircraft still in build process with engine attached)
There’s not many places to find information about it.
Your post was very informative. I’m wondering if you have pictures or a way that we can exchange some information.
Thank you very much.
I recently purchased a Zenith 601 with an NSI EA-81. Testimony and logs show good reliable service for 13+ years and 400+ hours. It has an NSI SFDI dual ignition that just went bad. Has two toggle switches to select A and B ignition systems. Both on – runs fine. A only – runs fine. B only – stumbles badly at half the RPM. Only two cylinders firing. Has four coils. Replaced one – same problem. Switched the coils around several ways – same problem. Switched the isolation modules. Ahah! Now ignition A is the bad one. Appears one of the two “isolation modules” (NSI # 101-17200-00) is the problem. Anybody have a clue where I might find a replacement?
I have an NSI/Subaru with the SFDI ignition that has the same problem except that on ‘B’ it dies completely.
Allen- Just now read your post. Do you know anyone who can diagnose/tuneup an EA-81? Fixed the ignition problem but now it’s running rough.
very nice discussion, thanks , however can you advise us which auto engine would be reliable for enthusiast experimental builder which terrified for price of aviation engine
best
It is impossible to respond to your inquiry as you have provided no background information on what you want to use it for, fast, slow, single seat etc.
Please provide as much information as possible.
Trevor
I wanted to ask if anyone knows anything about the Ukraine built AK 1-3 experimental helicopter that uses the Subaru 2.5 Boxer engine? They seem to have it worked out and solved the cooling problem.
John,
This link http://finleyweb.net/JonsStuff/Q2AircraftInfo/EJ22Conversion.aspx is redirecting to malware, I went there looking for info on the cooling system you used on your Subaru conversions.
Thanks Bill. Fixed now.
I am thinking of fitting a Subaru engine in a Viking dragonfly mkII, does someone know a person who already did this?
The comments keep going back and forth on if this is a good thing. I am not engine savvy guy but thinking of buying a Glastar with a NSI Subaru EJ22 170 HP. Owner has replaced the head gasket with the upgraded metal gasket and the duel fuel injection computers (as they failed) with a single computer build by some company in Calgary. I don’t have nay experience with FI engines only piston and jet. Engine has 100hrs on it. Does the single FI system risk wash against no carb ice? The plane looks awesome. Not sure which way to go with this. Is it safe and can I get it serviced and find parts?