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09-15-2008, 10:08 AM | #1 |
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EJ22T - lightest powerplant for aviation?
I am starting initial design for a powe rplant transplant in an experimental helicopter...the stock engine is good for 200 or so hours and then it is rebuild time. And the remaining drive train is a maintenance pig. Want to go gearbox and shaft in lieu of all the belts bearings and pulleys. My intial questions if someone would be so kind...
1. We need about 170 horsepower (depending on the actual final weight of the drivetrain of course). Is the EJ22T the best starting point for a lightweight powerplant? This is the most important first decision.... 2. If so, I know of a used car with EJ22T available to purchase for about $800, can rebuild that...not sure it is the cheapest route to start, but it seems to be at the moment. 3. What specific mods would you recommend that would achieve the 170 continuous horsepower, and maximize reliability? Remember, a helicopter runs at nearly full horsepower output continuously...actally more like 90% power at hover, then 75% for flight, continuously. These are just initial questions to see whether I am thinking in the right direction. The weight is the overriding concern, any ways to reduce weight are paramount. Thanks for any insight you may have.
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09-15-2008, 10:14 AM | #2 |
Scooby Guru
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The Ej22T is substantially heavier than a number of other EJ series engines because it's closed deck. An Ej25 may be a better starting point.
Unless you are planning on rebuilding the engine yourself, I suggest you contact Colorado Component Rebuilders. All they do are Subaru engines. 2/3 or more of their business if for the homemade airplane and helicopter market. They are experts on what you are doing. At $800 that Ej22T powered car is well price and you can make some money on that engine. It is a very desireable engine for other applications and you can help fund your project if you have the time and ability to part out that car. |
09-16-2008, 10:40 AM | #3 |
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Vehicle:1990 Legacy & OB XT AWD 6MT EJ22T AWIC Swap |
Other thing to note about the EJ22T is that its aluminum is of a slightly denser alloy then the non-turbo EJ22's.
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09-16-2008, 10:56 AM | #4 | |
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Quote:
Thanks for the info. I called CCR, they were very helpful. I am still not sure however which engine will be the lightest, are you sure the 25 will be lighter than the 22? I figure the only thing I can do now is buy that old car, pull the engine and all the other little tidbits that might be needed, and initially part out the rest, and deliver the remaining to the scrap yard. Is there anything of value other than the engine (it's a Legacy Wagon) that would be attractive on Ebay? It is quite possible however this will become a fruitless exercise, if that happens and I offer up the engine and all the removed engine goodies on these boards or Ebay, what will it bring? I think the project is close enough that with some weight reductions of heavier cast aluminum parts on the airframe and ancillary engine parts (intake for example) enough weight can be reduced to put the drivetrain well enough near the stock empty weight so as not to greatly exceed the stock max gross weight. That is the goal after all. The stock engine is about 125 horsepower! |
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09-16-2008, 12:22 PM | #5 |
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I think an EJ22T is a good place to start.
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09-16-2008, 01:09 PM | #6 |
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i would also vote -1 for the 2.2t
as you would need to add the turbo and manifolds its substantially heavier than the 2.5 |
09-16-2008, 01:47 PM | #7 |
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a turbo motor might not be the best place to look for a reliable engine. NA motors are usually a little better with that.
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09-16-2008, 01:50 PM | #8 |
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The EJ22T is quite possibly the most reliable motor Subaru has ever built. I had almost 400,000kms on the legacy I had still on the stock motor. The motor ran flawlessly too.
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09-16-2008, 03:04 PM | #9 |
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Isn't an EJ22T good for 230 horsepower? Or did I read that wrong somewhere? Maybe that was the foreign twin turbo I saw specs on...
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09-16-2008, 03:30 PM | #10 |
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If I may speak for the OP for a moment, no matter the engine platform he will need to remain turbo. Remember aircraft reach high altitudes where the air pressure drops. Every 10k feet is like 2/3 the power at sea level. A low boost turbo will keep the engine from "leaning out"
I think the most important question is "What engine management will he be using" If he can go aftermarket my vote goes for EJ20 since they are a dime a dozen. My second vote goes for an intercooled low boost EJ25. A 99+ ej25 will probably already make 170hp since he will mount a custom exhaust and even 18psi manifold pressure (+4 over sea level) would probably put it near 200 with an intercooler. The RS25 guys have plenty of experience turboing the EJ25 before the 04 USDM STI came out. |
09-16-2008, 09:41 PM | #11 | |
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Now if I can figure out the actual final weight, we can determine if the project can possibly run. |
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09-16-2008, 10:32 PM | #12 | |
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Quote:
Ciper, The turbo really is discretionary. The vast majority of engines that CCR builds for the homemade airplane crowd are NA Ej22e's. They install a Delta cam in them that gives them an extra 15hp over stock and when freed from the restrictions of the factory intake and exhaust they are fine for most of those guys. cornwallav8r, With a non-restrictive intake and exhaust along with a set of cams, an otherwise stock Ej25 engine will make more than 200bhp at sea level. You can read all about my car if you go search in the NA forum, but I will give you the relevant details to try and convince you that you do not need to turbocharge that engine for your use. I live at 5000ft. When I had just an intake, headers with high flow cat, and cams, along with lightweight flywheel and pullies, I put down 119 whp on our local dyno. That's an uncorrected number. That's the real power up here without any compensation for altitude to make it look like an SAE sea lever number. We use a very aggressive dyno here that it known for reading low. Conservative numbers generally put the drivetrain loss of our AWD drivetrains at about 35%. Based on that, my engine was actually making 183chp at that point. That hits your number with a bit to spare. That was on a stock factory ECU with no additional tuning control. So, what I am saying here is that you very well may be able to avoid the added weight and the complications of a turbo. It's your project and you will do what you want, but I just want you to know that it really isn't required based on the performance parameters you have presented to us. |
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09-16-2008, 11:19 PM | #13 | |
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Your candor and interest on the project is most appreciated. If I can indeed make that kind of horsepower up to 5,000 feet, I am more than happy to drop the turbo. Really! Here is the snag... Given my situation, with time available to develop something to help the many other owners sick of underpowered unreliable powertrains, it is in all of our best interest to generate a one-size fits all, so that it can be duplicated and made available as a kit. But if the turbo can go, ALL THE BETTER. But what about those guys at 10k feet elevation who are experiencing the factory's crappy failing "ACIS" supercharger, with blown pistons and shredding belts? Is a normally aspirated engine going to supply 170 horsepower on a 95 degree high humidity day? That's the rub. But if so, then great. Keeping in mind the ACIS only tries to maintain the factory sea level performance of their stated 150hp (really about 125 to 130 depending on who you talk to). So what I am asking is...can or should I do both? Can I develop around the EJ25 w/o turbo...and add it back in for those who need it? Is it as simple as a head gasket change (reduce CR) and a turbo add and ECU programming? Or is there more to it? Or is it that I need to plan on entirely different EJ25's purpose built to be NA or turbo'd from the start? For my own personal situation the EJ25 w/o turbo should work fine, I agree now. But I guess I would have to run it at higher rpm than I am comfortable with. Matt you said "When I had just an intake, headers with high flow cat, and cams, along with lightweight flywheel and pullies, I put down 119 whp on our local dyno." At what rpm? We need this engine to put out constant power, and if the power is up at the engine's max, it will melt down in short order. You street guys never put the demands on your engines that a helicopter does. Just reality. Constant versus intermittent. My buddy developed his own helicopter from scratch using the EJ25, and I would be using his drivetrain design (google: Kinney HRH). Hadn't put much thought into the intake and exhaust restrictions but I guess that is an important distinction. So I guess if the weight can get into the ballpark (I suspect carbon fiber parts are in order to assist with this) and if the demanded output from the engine isn't over say, 75% of the engine's max output on a constant basis, this might work. Coincindeltally I got a call back from a major air cooled engine builder. He thinks he can make over 200 hp easily. The problem with that is, these machines are covered in fiberglass panels. It would be a major engineering challenge to get air cooling to work. That alone would take 2-3 years of wrok and would likely fail. On top of an overstressed air cooled engine and the constant diligence required by the pilot due to the ease of overtemping. |
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09-17-2008, 09:52 AM | #14 |
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Let me dig out my old dyno sheet and see what we are looking at for numbers. IIRC, peak HP was at 5800 rpm, which is probably too high for you. But it also shows a very constant torque curve and if memory serves that peak hp number of a little bump at the end than anything else. I do understand you application and specific needs. I've got a buddy whom I have been helping to develop a Bonneville car. The RPM issue comes up there in the same way because at the salt flats the biggest challenge is getting an engine to hold together until the end of the run at a constant very high rpm that one never sees in a street or any other form of motorsports usage. Your application is not dissimilar other than the fact that you will run it 1500rpm or more lower so that instead of holding together for 5 minutes the engine can run for several hours at a time withouth failure.
Any chance that air cooled builder you are talking to is Raby? If so, his engines are going to run you $10,000-15,000 for the power levels you are talking about. To answer your question about NA versus turbo Ej25, I personally do NOT support turbo charging the NA Ej25 in stock form. Thicker headgaskets don't solve it because you mess up the timing when you do that. Being a flat 4 configuration you are retarding one side while advancing the other side an equal amount. Personally, I feel that the only correct way to turbocharge them is to add in an STi shortblock or to put STi pistons into the NA engine case. |
09-17-2008, 12:39 PM | #15 |
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this thread scares me...
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09-17-2008, 03:40 PM | #16 |
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Go To Youtube And See The Different Subaru Powered Helicopters Pretty Awesome. And There Turbo Charged! Im Impressed.. It Can Be Done.
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09-17-2008, 06:04 PM | #17 |
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NSI out of Arlington, WA has been building EJ series motors for airplanes for years. Truely beautiful work from what I hear. I have tried to find their website several times but have failed. Here is an description of the company. I would get in contact with them as they are the experts in this field. Good luck ;
NSI engines are converted from Subaru automobile engines and are built and marketed by NSI Propulsion Systems, Inc. of Arlington, Washington. NSI sells their conversions to builders of homebuilt, experimental aircraft. NSI was founded in 1993 in its present form. All NSI Subaru conversions require reduction of propeller rpm from that of engine rpm; i.e., a Propeller Speed Reduction Unit (PSRU). The NSI PSRU incorporates planetary spur gears and are of the firm's own design. Most of the information here has been compiled from the NSI Website as well as "Kitplanes" (KP) and "Sport Aviation" (SA) magazines. The applications below are available as firewall-forward kits for the various New Glasair, Van's, and Zenith kit aircraft. All of the NSI engines are non-certificated engines for use in experimental, homebuilt aircraft. Not sure if any of this has any relevance to helicopters but just thought I would share |
09-17-2008, 06:51 PM | #18 | |
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Quote:
My suggestion for the turbo'd ej25NA was to maintain linear performance no matter the altitude. I have no experience with aircraft so I'm not sure if its an issue but at least this way the ECU would see a continuous airflow for the RPM during takeoff and cruise. |
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09-17-2008, 08:53 PM | #19 | |
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09-17-2008, 09:51 PM | #20 | |
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Absolutely, did I fail to mention? Look at the Ukraine produced 2-seater. I forget the name of it. Sweet machine. It is just what I want to do, they are also using an EJ25. I just want to run the numbers and make sure what I am doing is going to be ok. |
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09-17-2008, 09:54 PM | #21 | |
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Lowest weight, lowest cost, and highest reliability are the goals here. Not necessarily in that order. I can post a pic of my machine if you want, and it is allowed, not sure how to do it though. Here is the Subaru from the Ukraine....http://www.aerokopter.co.za/Technica...ifications.htm Last edited by cornwallav8r; 09-17-2008 at 10:00 PM. |
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