Nad_1990245 Posted May 10, 2015 Share Posted May 10, 2015 (edited) Hello all, Disclaimer: This is a benchracing/build list thread for now until I actually get the ea81 hatch that I want to put this beast into. My idea is for a modern drivetrain for an all-weather sporty hatchback with an admittedly heavy emphasis on sport. I've been doing alot of reading and I haven't seen any threads pertaining to these specific questions I have about pulling the trigger on starting to collect parts for this. I'm very interested in building an ej22t "reverse" frankenmotor with 2.5 SOHC heads. My idea is to gain the strength of the closed deck block as well as combining this with the lower compression, better flowing roller rocker SOHC heads for the ability to run some real boost! This would be paired with a WRX TD0516G turbo as I feel this would give both quick,relatively lag-free spool and a nice boost curve with this engine. I would like, if all possible, to stick with the SOHC heads so as not to have to mod the framerails on the EA81 car. While DOHC is not completely out of the question, I would rather try to spend the effort to use the SOHC heads rather than cutting up the car, if possible, but if DOHC ends up being the "answer", then I would do that. Questions: 1. I have read that the SOHC heads coolant passages do not match the closed decks at all and should not be used. I have also read that they match well enough to be used. Has anyone out there tried this or definitively know an answer to this? 2. In the event that the 2.5 heads are a no-go, could a thicker headgasket be installed on the 2.2 heads to lower compression instead? 3. Which intake should be used? 2.2 or 2.5? Thanks in advance for any answers! Edited May 10, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Subruise Posted May 10, 2015 Share Posted May 10, 2015 (edited) I have the hatch for ya...its only a couple thousand miles away heres something that may be useful http://legacycentral.org/library/literature/headswap.htm Edited May 10, 2015 by Subruise Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 10, 2015 Author Share Posted May 10, 2015 (edited) I read that earlier today, it was helpful but still not specific enough to satisfy me Particularly the part about the bore mismatch since we have headgaskets being made for these swaps plus the fact that the car will be turbo-d. My main reason for the 2.5 heads is the lower compression, the superior flow is just a nice bonus. And yeah, I would kill for your hatch but I don't have that money right now. I was going to start looking in earnest next Jan/Feb @ tax time...if you still have it then (highly doubt it!)....then maybe! PS - that car...is it a 4 or 5sp D/R? Edited May 10, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Subruise Posted May 10, 2015 Share Posted May 10, 2015 4spd. but I have a single range 5spd I was going to put in there. its all shiny too 1 Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 10, 2015 Share Posted May 10, 2015 There is no bore mismatch with sohc ej25 heads, they have the same combustion chamber as the phase 2 ej222. And you can use off the sheet gaskets, either the 1.5mm ej22t or 0.8mm 99-01 ej222 gasket will be right for this build, which one you use depends on where you want your compression ratio. 1 Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 10, 2015 Share Posted May 10, 2015 Just for reference this is a 00 ej251 head with a 90-98 ej22e gasket sat on it. 1 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 Sweet, so the bore "mismatch" seems to be a myth. Bratman, I've come across some other posts you've made on these frankenmotors and they were very enlightening. Do you have knowledge of or an informed opinion about about the cooling passge "problem" with the closed deck ej22t block and the ej25 SOHC heads? Is it nothing to really worry aout so long as the cooling sytem itself is up to par, or is there little room for error? I tried to see how the gasket sits with the ports in relation to the head and the only place I can see in that extremely helpful pic is that upper hole inbetween the cylinders looks a little off, but it may just be the pic. Thanks for that, it was very helpful, all of the reading I had been doing was leading me to say screw it and just run the ej22t as is, but I like to be different when I can Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 4spd. but I have a single range 5spd I was going to put in there. its all shiny too shiny...... Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 11, 2015 Share Posted May 11, 2015 (edited) That head gasket is for the NA ej22e, the coolant ports on them are different from what is needed for this application. I took this picture several months ago to illustrate that the sohc ej25 heads were suitable for use on an ej22 bore,at the time those were the only ej22 gaskets I had laying around. You would need 99-01 phase 2 ej222 gaskets or 91-94 ej22t gaskets for the coolant ports to match the heads in this application. I haven't seen any indication that the coolant ports are different enough to be an issue with sohc ej25 heads on the ej22t. But there are several issues worth noting for what you're wanting to build and the car you're putting it in. First is just a general issue with using phase 2 sohc heads in a turbo application. There is interference between the uppipe and the head, you can make it work but I'm not sure what it entails. Searching on rs25.com or nasioc should provide the answer to that. Second is another issue using those heads on a turbo application. There is no provision for oil or coolant feed and return on them since they were never offered with a turbo. There are ways around that, one of which is to use an oil galley plug adapter to feed oil to the turbo, which is something not hard to do. The drain can be tapped into the valve cover quite easily, but this will be cutting it close on space in the ea81 engine bay. Coolant is usually an easy fix on na-t ej251s since all ej era cars have constant coolant flow through the heater core. On these cars you can plumb the turbo in-line with the heater hoses. This will be a no go in the ea81 car because there is a heater control valve that shuts off all coolant flow to the heater core when the dial is turned off heat. So you would either have to run with the heater control valve open or plumb in a secondary bypass system to feed the turbo independently of the heater core. A more minor problem is that the uppipe support brackets won't mount to the phase 2 sohc heads, something could be fabbed to work though. All in all if it were me I would keep stock ej22t heads for this application, just to simplify things. All the other mods needed to run the turbo on the phase 2 sohc heads would create potential failure points down the road. And there is decent potential in the ej22t heads as they are, a properly done port and polish, along with swapping in 96-98 ej22e cams and rocker rockers would really wake the engine up. And let's face it, even stock ej22t power in an ea81 hatch will feel like a rocket compared to the 73 hp they came with. Edited May 11, 2015 by 86BRATMAN 1 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 There is no bore mismatch with sohc ej25 heads, they have the same combustion chamber as the phase 2 ej222. And you can use off the sheet gaskets, either the 1.5mm ej22t or 0.8mm 99-01 ej222 gasket will be right for this build, which one you use depends on where you want your compression ratio. I like the idea of the thinner gasket as I believe that that would put me somewhere in the neighborhood of 8:1 versus 7.59:1 (calculations done with data found online plugged in to the static CR calculator found here: http://www.rbracing-rsr.com/compstaticcalc.html Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) That head gasket is for the NA ej22e, the coolant ports on them are different from what is needed for this application. I took this picture several months ago to illustrate that the sohc ej25 heads were suitable for use on an ej22 bore,at the time those were the only ej22 gaskets I had laying around. You would need 99-01 phase 2 ej222 gaskets or 91-94 ej22t gaskets for the coolant ports to match the heads in this application. I haven't seen any indication that the coolant ports are different enough to be an issue with sohc ej25 heads on the ej22t. But there are several issues worth noting for what you're wanting to build and the car you're putting it in. First is just a general issue with using phase 2 sohc heads in a turbo application. There is interference between the uppipe and the head, you can make it work but I'm not sure what it entails. Searching on rs25.com or nasioc should provide the answer to that. Second is another issue using those heads on a turbo application. There is no provision for oil or coolant feed and return on them since they were never offered with a turbo. There are ways around that, one of which is to use an oil galley plug adapter to feed oil to the turbo, which is something not hard to do. The drain can be tapped into the valve cover quite easily, but this will be cutting it close on space in the ea81 engine bay. Coolant is usually an easy fix on na-t ej251s since all ej era cars have constant coolant flow through the heater core. On these cars you can plumb the turbo in-line with the heater hoses. This will be a no go in the ea81 car because there is a heater control valve that shuts off all coolant flow to the heater core when the dial is turned off heat. So you would either have to run with the heater control valve open or plumb in a secondary bypass system to feed the turbo independently of the heater core. A more minor problem is that the uppipe support brackets won't mount to the phase 2 sohc heads, something could be fabbed to work though. All in all if it were me I would keep stock ej22t heads for this application, just to simplify things. All the other mods needed to run the turbo on the phase 2 sohc heads would create potential failure points down the road. And there is decent potential in the ej22t heads as they are, a properly done port and polish, along with swapping in 96-98 ej22e cams and rocker rockers would really wake the engine up. And let's face it, even stock ej22t power in an ea81 hatch will feel like a rocket compared to the 73 hp they came with. Yes, the more I read the more I am leaning towards just using the ej22t as is - the money spent on buying the heads could instead be used to port and polish the 22t heads or just a bunch of dremel bits and just port match everything I was fine with drilling and tapping oil feeds and I already had a plan to cut the flange off of the uppipe and weld it to a custom pipe. The coolant issue would be a little more annoying, but as you mentioned could have been dealt with. All in all, it is alot of extra work/fail points. I do like being different, but not at the expense of longevity/reliability. I don't have the wallet for that . So that's the end of that particular road...off to investigate thicker headgaskets! Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 11, 2015 Share Posted May 11, 2015 Honestly it's probably not going to be worth lowering the compression any lower than the stock 8:1 on the 22t. It's already lower than pretty much any modern turbo engine, and right in line with the turbo engines of its era. The off boost driving would be fairly sluggish, and it would increase the spool time of the td05 you're wanting to run. Money would be better spent on a set of na ej22e fuel rails, sti yellow top 525cc injectors and a rob tune ej20g ecu. With some port work to the heads, and the above mentioned supporting mods you'd be in the 250 crank hp range with a decent bit more torque since that's where the ej22e/t heads shine because of their port design. 2 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) Bratman, I applaud you for coming forth with this info! On the other hand, I curse you because I now have a TON more reading to do . I'm not new to subarus, but anything made past 1990 is new to me lol. I used to do alot of work on ea81 and ea82 engines, having owned a GL hatch and a GL-10 wagon in the past. My father was an agricultural diesel mechanic and as such, alot of farmers used to drive subarus as they liked the 4WD and having a roof to go fix fences with. Because of this, I got to be known as "that kid who's good with these crackerboxes and their weird engines" lol. Anyway, your suggestions look fantastic and should be a perfect fit for the GL hatchback's "personality". I'm going to keep this thread going as I progress and as time goes on, will put build details in here which should make a neat chronological record of this project from conception to finish. So, to that end, feel free to contribute whatever you wish! Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) I have found an ej22t for sale locally for $350. A friend of mine has it. It's in a 1994 legacy that is whipped to hell. The motor has 222k on it and it runs well. Is this a good candidate? Any engine I buy will be getting a full rebuild anyway, so miles don't really concern me as long as the bores look ok. It certainly is cheap enough, but I am wondering if I should be looking for a later (post 1995) engine with an eye to the future as far as having the OBDII ports available to be able to troubleshoot and read codes. Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
jmoss5723 Posted May 11, 2015 Share Posted May 11, 2015 If you can find the parts for the right price, you could buy that motor and the manifold off of an OBDII car and swap it on. 1 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) So, sensors did not change between OBDI and OBDII, just ecus,wiring and manifolds?...interesting if true, that's very helpful! Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) Browsing on car-part.com has revealed multiple AWD 5MT from $250 to $1000. I ran a search for 1996 Legacy (non-outback) 5MT as I believe, according to various sources, that these are 3.90 final drive transmissions, which I feel is perfect. Thoughts? There are also XT6 5MTs available there as well. Is the newer Legacy 5MT more robust or are they the same? I am uncertain since I am unsure if the 5mt behind the EG27 is EA based or was ahead of its' time and was the basis for the later EJ transmissions? Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
jmoss5723 Posted May 11, 2015 Share Posted May 11, 2015 (edited) So, sensors did not change between OBDI and OBDII, just ecus,wiring and manifolds?...interesting if true, that's very helpful! This should get you started in the right direction: http://www.ultimatesubaru.org/forum/topic/153396-95-subaru-impreza-l-18-liter-more-power/?hl=%2Bej22+%2Bobdi+%2Bobdii&do=findComment&comment=1284413 I only mentioned this because I was doing some research of my own the other day and came across that thread. I haven't done it myself, but it sounds reasonable enough to me. If someone chimes in with different info, don't take this as the gospel. Edited May 11, 2015 by jmoss5723 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) Thank you for that thread, it would appear that all that is needed is to procure an OBDII engine harness (for the plugs and scanner ports), matching era intake and wire it up. It would seem that the task is essentially the same whether it's OBDI or not. Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) As this project stands now: EA81 Hatch EJ22t engine Legacy 3.90 final drive 5MT AWD transmission and AWD 5MT from RX or XT6 as per this thread: http://bbs.legacycentral.org/viewtopic.php?f=7&t=53943 (Looks very simple to do!) TD0516G Turbo STi yellow top 525cc injectors rob tune ej20g ecu OBDII engine and dash (for trouble codes) harness Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 11, 2015 Share Posted May 11, 2015 Obd 2 wiring harnesses are laid out in a way that it's much easier to strip and run for a swap into an ea series car. Basically all the sensors will interchange with the exception of the tps, 90-94 use a 4 wire and 95-98 use a 3 wire. The cam and crank sensors are also different, but can be made to work since the output signal is identical. But, you won't find an obd2 ecu that can run this turbo engine as it should, and the rob tune ecu won't plug into the newer harness. Added to that there are no ej20g ecus that are obd2 equipped, so that negates the benefits of the newer harness. Would be best to just stick with a 91-94 turbo legacy harness (or na harness and add the wiring for the boost control and other turbo specific items) and run with that. You can still retrieve codes fairly easily with subaru obd1 electronics, and there are a few data logging softwares available specifically for them, again basically negating the obd2 being a better option. 1 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 agh, goddammit lol. That was info that up till now I could not find, thanks again Bratman! Edited project summary to reflect this. Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) As this project stands now: EA81 Hatch EJ22t engine Legacy 3.90 final drive 5MT AWD transmission and AWD 5MT from RX or XT6 as per this thread: http://bbs.legacycentral.org/viewtopic.php?f=7&t=53943 (Looks very simple to do!) TD0516G Turbo STi yellow top 525cc injectors rob tune ej20g ecu '91-'94 Legacy Turbo harness Edited May 11, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
Nad_1990245 Posted May 11, 2015 Author Share Posted May 11, 2015 (edited) Decided to also add prices to the build list. These prices are either what I can get locally or what I have found online. Subject to change, of course, but useful for both myself and others who may come across this thread with similar aspirations. (Incomplete and in progress as I research)EA81 Hatch - $$free all the way up to $4k (probably looking at in the $1200-$2200 range for a solid runner with good body from out west)EJ22t engine - $350Legacy 3.90 final drive 5MT AWD transmission and AWD 5MT from RX or XT6 as per this thread:http://bbs.legacycentral.org/viewtopic.php?f=7&t=53943&p=427585 (Looks very simple to do!) Legacy 3.90 5MT - Can be had for as little as $200+p/u.RX/XT6 5MT for "poor man's DCCD" mod - Can be had for as little as $150(!) plus p/u.TD0516G Turbo - New = as little as $205 on fleabay up to $1000 from Precision. Used=??STi yellow top 525cc injectors - New = $100x4 Used = I found a set of 4 on CL for $100.550 rob tune ej20g ecu plus 4to2 ignition converter: $350 (includes shipping, also assumes you are shipping ECU. $455 if he provides ecu for you.)'91-'94 Legacy Turbo harness - varied between $65-$150 for complete engine side and $50 for dash side. Edited May 13, 2015 by Nad_1990245 Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 11, 2015 Share Posted May 11, 2015 To run the xt6 transmission you'll need an ea2ej adapter plate, and it will limit your clutch choices to, well very little, unless you have a custom clutch made. And having driven both stock ej viscous center awd transmissions and center lockers, for street duty you want the viscous coupling awd. The locking unit while unlocked can present very, unpredictable wheelspin situations while taking curves and accelerating. And when locked will push through like truck in 4wd. While the rx/xt6 center diff swap is a novel idea, it is relying on parts that were never designed to take the power you're looking at making, even though it will be stressed to a lesser degree in the lightweight body. Link to comment Share on other sites More sharing options...
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