97 Legacy engine build
Thread Starter
Registered User
Joined: Feb 2003
Posts: 59
From: Chicago, IL
Car Info: 1997 Subaru Legacy Outback
97 Legacy engine build
So a belt tensionor disintegrated on my 97 outback and snapped the timing belt and bent 6 exhaust valves. The engine has 216k miles on it, so I've been waiting for an excuse to replace the engine. Well here goes the new rebuild specs:
Brand spanking new Phase II block
ACT pro street flywheel and exedy organic clutch with lightened flywheel
DOHC heads are getting 3-angle valve job, ported/polished, milled to increase compression. New springs in preparation of cam regrinding when the 12mo/12k mile warranty runs out on the engine.
Ported/polished intake manifold.
It should be a fun little station wagon. After I recoop from the work being done, I'm going to get equal length headers and a full exhaust to complete the job. I may slap a supercharger on it but I haven't thought that hard. I hope to be around 180-190hp by the end of the work.
Brand spanking new Phase II block
ACT pro street flywheel and exedy organic clutch with lightened flywheel
DOHC heads are getting 3-angle valve job, ported/polished, milled to increase compression. New springs in preparation of cam regrinding when the 12mo/12k mile warranty runs out on the engine.
Ported/polished intake manifold.
It should be a fun little station wagon. After I recoop from the work being done, I'm going to get equal length headers and a full exhaust to complete the job. I may slap a supercharger on it but I haven't thought that hard. I hope to be around 180-190hp by the end of the work.
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The thing is, and im not trying to knock your knowledge about subys but there are some serious flaws in your so called engine build up.
First- You need to consider use of the car( track only, rally, dailydriver ect.)
Second- You need to have a HP goal That corresponds with your budget, Which if you can afford all those parts you talked about could be a whole lot higher than 180-190.
Third- Realistically the EJ25 is not a very good motor for building power (see post under Overheating/cracked cyl section)
Lastly- If all you are looking for is 180 to 190 HP try a replacement longblock from subaru i think there like $6,800 but they also have a decent warranty then slap on the headers and clutch and maybe a few other bolt ons, take it to a qualified dyno tuning shop and have them tweak your ECU for those particular parts. ( I know from experience My best friend had his 2.5 RS blow and he did exactly that and now he basically has a brand new 1998 2.5 with 205 HP with a warrany) If you seek max power per dollar consider an engine swap for 2-3K you can find used USDM or JDM wrx motors and its a pretty straight forward bolt in
and will be 227 HP or close with no bolt ons.
Once again im not knocking your knowledge i just think that there are cheaper and better alternatives to building a EJ25 especially if you want to boost it
First- You need to consider use of the car( track only, rally, dailydriver ect.)
Second- You need to have a HP goal That corresponds with your budget, Which if you can afford all those parts you talked about could be a whole lot higher than 180-190.
Third- Realistically the EJ25 is not a very good motor for building power (see post under Overheating/cracked cyl section)
Lastly- If all you are looking for is 180 to 190 HP try a replacement longblock from subaru i think there like $6,800 but they also have a decent warranty then slap on the headers and clutch and maybe a few other bolt ons, take it to a qualified dyno tuning shop and have them tweak your ECU for those particular parts. ( I know from experience My best friend had his 2.5 RS blow and he did exactly that and now he basically has a brand new 1998 2.5 with 205 HP with a warrany) If you seek max power per dollar consider an engine swap for 2-3K you can find used USDM or JDM wrx motors and its a pretty straight forward bolt in
and will be 227 HP or close with no bolt ons.
Once again im not knocking your knowledge i just think that there are cheaper and better alternatives to building a EJ25 especially if you want to boost it
Thread Starter
Registered User
Joined: Feb 2003
Posts: 59
From: Chicago, IL
Car Info: 1997 Subaru Legacy Outback
I was definately being conservative with the HP numbers since I don't like to boast too much and it is pure speculation until i dyno it. I'm already getting all the engine work done for ~$5200 so the budget thing isn't much of an issue for that price range.
Yea I'm not trying to make this a track car or anything, basically the heads are getting reworked and I decided that doing the extra work wont hurt and I needed something a little fun since I'm trying to sell my 2002 A4 to reduce montly overhead (selling cheap hit me up for info). I would had loved to put in a wrx motor but since I do take the car off the beaten path sometimes I didn't want the anemic torque of the EJ20T below 1500 rpm (and it's my girlfriends car that I bought for her to use to haul the baby around, so I don't want her being intimidated by big turbo speed). Sure it could be enough, but I really appreciated the torque last summer when I was driving up a very unmaintained mountain road in Canada with 4 people, 2 dogs, and hiking gear following a jeep in 4-low w/o trouble.
The block was from Subaru for $1800, so I'm satisfied with that. I was going to have them put in high compression pistons, but I honestly don't want to spend the $900 + labor for them to do it, especially if I am going to eventually slap a blower/turbo on it at some point after break-in if I can recover from this work fast enough. After I get the exhaust all done I'm going to get the ECU tuned to take full advantage of it. Do you think any tuning shop can modify the ECU, or will I have to get a piggy back module and have that tuned?
I'm just lucky the car is paid for (bought it last spring) for $4500 so this seems the appropriate thing to do since I love the car, put in the cost of a new car to make this car a new car in the same body and get another 216k miles out of it.
EDIT: It's been some time since my last post, and 63k miles. Life and all... I have brullen equal length headers, high-flow cat, cat-back from an Impreza fitted (add about 5.5" w/ sleeves on the mid-pipe and you're gtg). Still on stock cams and ECU. I'm tempted to get cams first, but I also feel unlocking the ECU potential may be a better next step. Anyone recommend anything and can post install howto or results for S-AFC or the like? I'm tempted to bite the bullet and get 034efi.com Ic ECU... What do people think would benifit me the most? Any recommended dyno's in the Chicago area just so I can establish a baseline?
Yea I'm not trying to make this a track car or anything, basically the heads are getting reworked and I decided that doing the extra work wont hurt and I needed something a little fun since I'm trying to sell my 2002 A4 to reduce montly overhead (selling cheap hit me up for info). I would had loved to put in a wrx motor but since I do take the car off the beaten path sometimes I didn't want the anemic torque of the EJ20T below 1500 rpm (and it's my girlfriends car that I bought for her to use to haul the baby around, so I don't want her being intimidated by big turbo speed). Sure it could be enough, but I really appreciated the torque last summer when I was driving up a very unmaintained mountain road in Canada with 4 people, 2 dogs, and hiking gear following a jeep in 4-low w/o trouble.
The block was from Subaru for $1800, so I'm satisfied with that. I was going to have them put in high compression pistons, but I honestly don't want to spend the $900 + labor for them to do it, especially if I am going to eventually slap a blower/turbo on it at some point after break-in if I can recover from this work fast enough. After I get the exhaust all done I'm going to get the ECU tuned to take full advantage of it. Do you think any tuning shop can modify the ECU, or will I have to get a piggy back module and have that tuned?
I'm just lucky the car is paid for (bought it last spring) for $4500 so this seems the appropriate thing to do since I love the car, put in the cost of a new car to make this car a new car in the same body and get another 216k miles out of it.

EDIT: It's been some time since my last post, and 63k miles. Life and all... I have brullen equal length headers, high-flow cat, cat-back from an Impreza fitted (add about 5.5" w/ sleeves on the mid-pipe and you're gtg). Still on stock cams and ECU. I'm tempted to get cams first, but I also feel unlocking the ECU potential may be a better next step. Anyone recommend anything and can post install howto or results for S-AFC or the like? I'm tempted to bite the bullet and get 034efi.com Ic ECU... What do people think would benifit me the most? Any recommended dyno's in the Chicago area just so I can establish a baseline?
Last edited by paulpas; Mar 10, 2009 at 08:39 PM. Reason: Update
The combination of a Phase II block and DOHC heads are going to increase your compression above 10:1 anyways. There's a bit of discussion over at NASIOC about such things in the N/A forum, pretty cool stuff. Turboing later would definitely warrant lower compression pistons in that combination.
ECU tuning for older ECUs is all but nonexistent. Piggyback units like the S-AFC would get you some performance though.
ECU tuning for older ECUs is all but nonexistent. Piggyback units like the S-AFC would get you some performance though.
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