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Old 02-14-2021, 11:21 AM   #1
je03672
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Default 02 WRX EJ257 Engine Replacement

Hi guys,

So my buddy has had a 02 WRX with a turbo EJ25 rotting in his yard for 6 years. I offered to buy it and heís basically giving it away. It turns out itís got an EJ257 in it right now with forged internals and the 2.0 heads. The current EJ257 block has a crack in it so iíve been looking for a new engine.

My original plan was just to buy a full EJ25 engine and then swap my heads onto that engine and drop the motor in along with a new ECU and injectors (current ECU is tuned for e85). I know nothing about Subarus so does this sound like the best idea? I saw an entire EJ25 engine with accessories that came out of a subaru legacy on ebay for a good price and I was thinking about going that route.

My other option was to just buy an ej25 short block and swap the forged internals from my cracked block to the new short block. This would be more work I understand but maybe this is a better idea?

Thanks again for the help,
Justin
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Old 02-14-2021, 04:05 PM   #2
GeoNV
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It would be pretty easy to swap the pistons over if the bore is the same size (not bored out to 99.75 or 100mm). But swapping the rods is way more work and unless you are looking for pretty crazy power levels probably not needed.

Probably have to do quite a bit of searching the faqs and such to get a bit more familiar before you make a decision. Thereís a lot of info needed to understand the hybrid set ups and tuning of them.
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Old 02-14-2021, 04:24 PM   #3
je03672
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Quote:
Originally Posted by GeoNV View Post
It would be pretty easy to swap the pistons over if the bore is the same size (not bored out to 99.75 or 100mm). But swapping the rods is way more work and unless you are looking for pretty crazy power levels probably not needed.

Probably have to do quite a bit of searching the faqs and such to get a bit more familiar before you make a decision. Thereís a lot of info needed to understand the hybrid set ups and tuning of them.
Gotcha, Iím actually leaning more towards dropping an ej205 directly in it for the time being and getting a new ecu and a remap for the turbo. While the ej205 is in the car iíll start building the IAG short block. Any thoughts about this idea or tips/tricks for my build?
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Old 02-15-2021, 07:56 AM   #4
snow_bound26
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You don't need a new ECU. Just get it tuned for your new set up. One thing to take into consideration since it seems like you're not sure what direction to go, is if you reuse the heads on it currently. If they have been chamber matches for the 2.5, then they can only be used with a 2.5 from now on. If they haven't, then you'll need a reputable machine shop to go over them thoroughly. Without chamber matching or the proper hybrid pistons, the hybrid setup creates hot spots/detonation and heads might be shot as well.
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Old 02-15-2021, 08:01 AM   #5
je03672
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Ok cool thanks, and yes they have been matched to the 2.5 bore.
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Old 02-17-2021, 12:39 PM   #6
je03672
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Ok so I went ahead and purchased an ej205 from JDMRacingMotors and I went ahead and also got a JDM ECU and harness so that I can utilize AVCS. I ordered a Tactrix open port 2.0 cable and I plan to use Shenji for tuning. Does it sound like im on the right track here?

Any thoughts or tips you guys might have?
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Old 02-17-2021, 04:35 PM   #7
snow_bound26
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Doing the swap is pretty straight forward. Wiring up the AVCS can be done by making your own harness which requires adding 4 wires plus a shield wire and re-pinning several wires. Or you can buy a pre-made harness through iA Tuning or iWire. Otherwise, just take your time and keep everything in order and we'll marked.
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Old 02-17-2021, 06:10 PM   #8
je03672
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Thanks, yeah he sent me instructions for use with his harness and it requires repin for like 8 wires along with moving the tgv
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Old 02-25-2021, 11:56 AM   #9
je03672
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Ok so my EJ205 got delayed and it finally comes tomorrow. Iíve got the old engine pulled and went ahead and cleaned up the engine bay. I also ordered a VF48 from someone on this site that I plan to install too. This should just bolt directly on right? Iíll be running the upgraded injectors from the old engine as well as an external waste gate for the turbo.

Tomorrow I plan to swap the aftermarket clutch to the new ej205 and resurface the flywheel along with a rear main seal replacement. Am I doing this right? Any suggestions? I have never worked on a Subaru before.
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Old 02-26-2021, 01:56 AM   #10
D-Rodman
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Default 02 WRX EJ257 Engine Replacement

Quote:
Originally Posted by je03672 View Post
Ok so my EJ205 got delayed and it finally comes tomorrow. Iíve got the old engine pulled and went ahead and cleaned up the engine bay. I also ordered a VF48 from someone on this site that I plan to install too. This should just bolt directly on right? Iíll be running the upgraded injectors from the old engine as well as an external waste gate for the turbo.



Tomorrow I plan to swap the aftermarket clutch to the new ej205 and resurface the flywheel along with a rear main seal replacement. Am I doing this right? Any suggestions? I have never worked on a Subaru before.


Itís time for you to move to the ej20 turbo forum.
Yes, the vf48 is a straight drop bolt on turbo.
Your fuel injectors ideally are dark blue oem 565cc or pinks for the vf48.
A new rear and front main seals are a good idea, valvle cover gaskets, new spark plugs and timing belt kit including water pump and thermostat should also be on the list.
Check the motor out really well before you put time and money into it.
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