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wrx swapped rs? from ej205 to ej207

4524 Views 56 Replies 9 Participants Last post by  heel.toe.tim
Just wanted to document the process i went through building my rs . vehicle started off as a mostly stock RS the only aftermarket part the vehicle had was a warm air intake
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after a couple of months of owning the car i really started getting the urge to modify it . at first i told my self "im just going to do exterior mods oem + look " well that was only halfway true .started with adding rep front lip ,fog light covers, coupe spoiler, pro drive axle back
Then i was able to find some of jdm bits and pieces eventually and found a old set of oz Cronos wheel and restored them
found a really cool piece from 6 over crest , hood induction scoop

eventually found v6 sti front seat and v6 sti cluster along with honeycomb grill
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Hmm, I had to work that weekend, sounded like a fun time...
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At this point i was baffled saying to myself "there no way motor is toast "i did a compression test on all 4 cylinder and cylinder 2 had 40psi of compression and cylinder 4 had 60psi . performed a leak down test to isolate failure found rush of air coming from oil cap . so out the motor went .
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removed cylinder 2 and 4 pistons , it didn't look good at all have no clue how it was running soo good
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was hoping that they were just cracked so i could replace with drop in forged pistons but due to cylinder wall damage i couldn't do that .
so I re-split case half's and inspected everything else
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after inspecting mains its possible i had mains set a lil tight or it could of been from multiple detonation events plus i was hovering around the max hp /tq the stock rods could take . it was sad to see but all i could do is make the car better from there take what i learned and build from there .
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now came the hard part how am i going to go about fixing i thought of plenty of different options , standalone ecu sky really the limit of what i could do .
1- (i could machine the bores and use a over sized forged piston and slap back together - i didn't like this idea would be cheapest option but i could still bend a rod )
2- (forged rods and pistons - the only weak point after that would be case design couldn't run super high cylinder pressures would be boost limited down the road)
3- (2.1 closed stroker from out front)
4- (2.5 hybrid ) had a 2.5 block laying around
5-(de stroked 2.3l) had some of the parts laying around to achieve this but due to assembly complexity thought it wasnt a good idea
6-(iag 2.5 block and d25 heads ) had that kicking around the shop but i didnt want to deal with wiring in the avcs for newer style cam sensors
7- (piece a 2.14 stroker motor together myself and send case half's to out front to close deck ( seemed cost effective at the time and wouldnt alter the set up too much )
the reason i stayed with 2l it revs freely and has a better piston to rod ratio . with the 2.1 you get a even better ratio nitrated crank and more toque

cleaned case half's and ordered rotating assembly parts
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shipped case half's to outfront in iag box lol
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while i was waiting for my block to return finally got the gauge pod i ordered 3 months prior
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looked way cleaner and you can still use upper cubby


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at this point i started getting ancy waiting and started thinking im going to put this motor together and it's going to grenade my trans
i weighed my option and sti 6 speed seem the way to go. after doing research i really wanted a 1CA prodrive gear box due to surtrac diffs ,sort gears and no complexity of dccd (epically after I found out how much a new center diff is 3-4k my cost .but at the time i couldn't find one for decent price , then i came across sg9 forester gear box that was low mileage ,came with shifter and had 06-07 sti gears

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a few weeks later i received my Outfront block back
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at this point i needed to really measure oil clearance .not trying to have this built motor eat it self so i bought new micrometers to help with spec the motor out
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after measuring main line clearance found first main had negative clearance and seemed way more eccentricity then others . every measurement was extremely tight barely in spec . something really didn't seem right so i brought everything to local machine shop do have a second set of eyes on it. after they measured everything they found the same thing and a couple of other things not 100% right. They found main line pinched and cylinders to wall clearance a lil to tight for Manleys piston recommendation. another issue i had was with the oem 257 nitrated crank they aren't 100%
consistent along main journals they are a few ten thousandths which kinda messed with oil clearance. i had to bring the machine shop 5 different crankshafts to find a more consistent crankshaft .
I emailed outfront and found out that they don't check main line after they close deck and wasn't able to provide specs that block was set to . at this point i was upset but couldn't be upset since i assumed they checked main line after close decking process . I decided to fully blueprint and balance block due to oil clearances being all out of whack . I wanted to have even oil pressure across all main clearanced to .00225 and rods clearanced .0020 to able to take more abuse and be able to hold together at higher rpm . to achieve those clearances i had to use stand x bearings and have main line and rods honed
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had rotating assembly fully balanced also
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after i got everything back from machine shop i went and double checked a few measurements and found to be spot on. confident in what i found, I went forward with assembly .
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After doing a few side jobs and saving up i acquired a set of used v8 sti big port heads . i originally was going to use my s20 heads but they were starting to crack around the spark plugs and cracks were almost to valve seats . i planned on swapping gsc valve train into t20 heads but when i had the heads professionally gone through , i was told valves matting surface thickness on gsc valves was out of spec which was weird for only having 4000 miles on them if that . at this point i could use stock jdm valves or buy new valves. i decided to go with manley extreme duty exhaust valves +1 and pro flow stainless steel intake valves.i wanted to future proof the heads incase i wanted to full send later on a big turbo set up or rotated
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while i was waiting for machine work on the heads to be done .I started a few side projects i was sitting on for the car .
rebuilt a set of front brembos and installed on vehicle and second project was installing a front external oil cooler
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the next project was fitting a external front oil cooler . this was pretty tricky because there technically not a kit available for this chassis unless u can source a old school greddy kit or hks kit .
i looked at tons of different places to install on google images, biggest hurdle is the car still has ac wich limit routing of lines most pictures i saw were straight race cars .it came down to installing in fender or installing in front bumper area . i decided to install in front bumper area due to stock bumper having some ducting i could use to funnel air into oil cooler instead of designing my own fender duct felt it was more susceptible to damage in fender since crash bar doesn't reach that area . i ended using a koyo 25 row oil cooler seemed to be decent core that would have minimal pressure drop and have adequate cooling
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i used 3 points to mount oil cooler 1 existing hole other to hole i had to rivnut . top right uses uper condenser mount between headlight mounting bolts. the lower left mounting point uses front crash beam as mounting point . the lower right uses a rivnut attached to fame and uses a rubber insulator to dampen vibration to take stress off o other mounts. please not u still have to clearance crash beam to get oil cooler to fit in this location and it takes a bit of cutting .
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once i got to this point i had to figure out hose routing i originally was going to go around frame and threw fender area . but after messing around with a couple ideas to make hose routing shorter found if i notched the frame slightly near passenger side next to condenser i could fit the lines around radiator
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if you notch frame just just right u can fit 2 -10 lines with sleeving
from this point i couldn't go any further until motor was i but i can show where the line route to the engine

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parts list
2x (m22 -10 setrab oil cooler sandwich plate adapters)

Setrab oil cooler sandwich plate and spacer

1x some sort of heat sleeve this worked the best for me after trying 3 different products

koyo oil cooler : Koyo Universal 25 Row Oil Cooler Black

8 feet of -10 lines of your choice suggest vibrant or fragola

2x (-10 65degree an fitting)

1x ( -10 straight an fitting)

2x (m22 orb -10 fittings for oil cooler )

you will need pack of stainless steel zip ties

fitting angles may change on oil filter side depending if you are running stock header


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after i finished the oil cooler mounting and routing i received my heads back from machine shop
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and they were ready to bolt on
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got both heads on and adjusted all valve buckets apparently valve adjustment is same from ej257 -ej205 -ej207 couldn't find anything stating different
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i was able to use 04 sti avcs hard lines everything lined up as it should also did another set of painted valve covers for new heads
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due to extra oil clearance and restriction reduction i decided to install 12mm jdm pump after extra research found out 12mm pump was used on spec c so my thought it wouldnt hurt
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side notes there a lot of question marks when comes to using these heads i found out after trial and error along with research u can use US 257 single avcs came gears on v7-v9 207 heads
the lh cam has trigger wheel on back side of cam just like jdm cams . you can also use single avcs 257 oil control valves you just need to bend mounting brackets or use spacers the only difference is connector orientation . the one thing u will have to by jdm is the rear cam sensors for avcs
jdm rear cam sensors pn: 22056aa091
you will also need passenger side 257 single avcs timing cover 205 timing cover will not clear avcs

finally got my hks equal length header from ceramic coater and got my iag oil pan from my tuner
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one thing i learned when trying to get ej205 intake manifold with iag fuel rails to bolt to 207 heads u need at least 8mm phenolic spacers to clear avcs solenoids u may be able to get better clearnce if use rcm rails which is designed based of ej207 engine

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at this point i had to find wiring diagram for jdm ej205 to wire in a custom overlay loom to wire in avcs sensors and solenoids u will need the following parts
1x multimeter you can do this with a cheaper meter i just recommend a auto ranging meter
2x ej257 injector connectors for rear avcs cam sensors
2x avcs solenoid connectors from any early 257 or 255 engine
22 gauge wire
18 gauge wire
wire loom of your choice i used braided loom and assortment or dual wall shrink wrap

open barrel crimps and crimper



2 conductor shielded wire: this is a lil hard to find this was automotive specific
you will need a scrap harness or find pins through i wire for engine harness to bulkhead female connector pins

in order to do this you will need some experience with depinning connector , crimping and also need to know how to use multimeter to verify connections
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this is what i used for reference if you have any additional questions on how i did this i can explain further

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you can also buy harness from iwire or iat
for me bought a new oem engine harness and used subaru wire repair kit for pins for engine harness connectors
i could save a few dollars by doing it my self
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at this point motor was ready to back in car with fresh exeddy lightweight flywheel and stage 1 hd clutch
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starting to notice my car moving into the direction of being track oriented i really didn't want any issues with fuel starving i would experience some sort of fuel slosh doing high way pull near the quarter tank mark so i decided to add a radium surge tank . i wanted to see if i could mount it in the engine bay where the washer reserve was or near frame rail near radiator . at the time there wasn't enough room to mount along frame rail so i went with mounting it where washer tank was
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it was pretty simple install hardest part was finding a spot low enough to clear hood for surge tank lines wiring i set up like a fuel pump hardwire which is wired off injector power circuit for a trigger
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the last thing i had to do was clearance electric fans to clear headers i don't recommend doing this as permanent solution just to get you going to your tuner for a base map . it did work though
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i eventually bought ebay fan shroud and replaced with davies craigs fans
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i recommend replacing fan connectors with DTM connectors to get weather proof seal or use stock connecters
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Wow, amazing build, thank you for sharing! Incredible attention to details! I'm down on the Long Beach Peninsula if you ever make it down this way! (SW corner of Washington State)
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Thanks I appreciate it just wanted to share some knowledge there were alot of things I had a very hard time figuring out and had to search old fourms to figure out or trial and error
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Great write up! Thanks for sharing your ups and downs.
Inspiring man! Thanks for documenting your build and please keep it going. I loved the pic of your manifold in the oven - I about got my ass kicked for trying that shortly after getting married. Again, thanks for sharing!
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Killer build bro. We had the same idea for oil cooler line routing by the condenser. clean AF!
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