I just finished building my motor and I thought that I would share my experience. I hope that I can help answer some of the common questions about swapping from a 2.0 block to a 2.5. My prior setup consisted of:

Stock EJ205 Block and Heads
FP TD06 20G Turbo
Tial 38mm External Wastegate
Pink Injectors
Walbro FP
TurboXS Front Mount Intercooler
HKS BOV
Perrin Uppipe
Invidia DP
Invidia Racing Catback
UTEC
Blitz SBC-id Boost Controller
And a few other small things

I made 355HP and 350TQ (corrected) on this setup and never had any problems. My car is a 2002 WRX sedan and had 49,000 miles when I decided to switch to a 2.5.

So, where to begin. The swap is very straight foward. Everything from the 2.0 block will swap over to the 2.5. This includes: oil pump, oil pan, water pump, thermostat, thermostat housing, intake manifold, power steering pump, alternator, a/c, accessory belts, motor mounts, timing belt, oil cooler, etc. Oh, and of course the 2.0 heads.
The gaskets are one issue that I would like to bring to light. I was told to buy a Subaru master gasket and seal kit for the 2.5 (STI) in order to do my swap. I would not recommend anyone who is doing this swap to buy it. It is far too expensive, has too many parts that are not needed/used and does not have all of the parts that you need. Instead, I believe that the gaskets and seals should be purchased seperately. I don't have part numbers on hand, but here is a complete list of gaskets and seals that you will need:

2.5 STI Headgaskets
Four WRX Camshaft Seals
Right and Left Valve Cover Gaskets For WRX
Spark Plug Hole Gaskets For WRX
Oil Pump to Crank Seal For WRX or STI
Water Pump Gasket For WRX or STI
Thermostat Gasket For WRX or STI
Intake Manifold Gaskets For WRX or STI
Water Jacket Crossover Pipe O-Ring For WRX or STI
Copper Turbo Oil Feed Banjo Washers
Valve Cover Bolt O-Rings
All New Exhaust Gaskets
One Tube Of Grey FujiBond

*the STI intake cam seals will not work with wrx cams
*the STI valve cover gaskets will not work with wrx valve covers

I believe this is everything, but please correct me if I am wrong. If you are doing TGV deletes you will want to get gaskets for them. If you are swapping your own pistons you will need the appropriate gaskets for that as well. Check out 2phless's thread for more information on these gaskets.

http://forums.nasioc.com/forums/showthread.php?t=996220

There were only two "problems" that we ran into during the swap. The first was getting the cam sprockets off. This seems to be a common problem, but can be accomplished with the right tools. You will need a strap wrench, large crescent wrench and a breaker bar. Have someone hold the strap wrench around the sprocket, another hold the crescent wrench onto the flat spot on the camshaft and another loosen the bolt using the breaker bar. It will take quite a bit of strength to get them off, so don't be affraid to get rough with them. The second problem was with the oil pan. I don't think this is common, but we had an issue with mine. Subaru doesn't use a rubber gasket for the pan, but rather silicone gasket (FujiBond) which bonds the block and pan togehter. We had to gently pry the pan off of my old block which caused small dents in the pan's lip. We tried straightening it back as well as possible, but we didn't succeed. It ended up leaking and I replaced the pan to avoid the problem again. So, be very careful when you take off your old pan and try not to put dents in it.
I thought I would share the cost of everything so you can have an idea of how much you would need to spend to do a comparable swap. Keep in mind that the prices I paid may not be the prices you will pay. I'm sure I overpaid for some things and got a deal on others. Anyways, here is a list of everything I bought and the prices I paid (shipping and taxes included):

Worldone Performance Stage 2 Block $2,455.00
ARP Headstuds $180.00
Crower Stage 3 Cams $850.00
Crower Valve Springs and Titanium Retainers $250.00
Supertech SS Nitrided Valves (standard size) $275.00
Perrin GT35R Rotated Turbo Kit $2,470.00
Perrin Rotated Turbo Intake Kit $320.00
Exedy Stage 1 Organic Clutch $395.00
STI Group N Motor Mounts $95.00
Power Enterprise Kevlar Timing Belt $175.00
STI Gasket and Seal Kit $300.00
FujiBond $25.00
Timing Belt Tensioner $156.00
Water Pump $131.00
Surface Flywheel $10.00
Modify Oil Line for 35R (to work with 2.0 heads) $35.00
PCV Valve $10.00
Timing Belt Bearings $50.00
Alternator Belt $20.00
Valve Cover Bolt O-Rings $10.00
Thermostat and O-Ring $15.00
Battery $80.00
Oil Filter $9.00
Oil (Mobil 1 5W30 non-synthetic) $20.00
Valve Job, Heads Decked, Valvetrain installed, Valve Seals, Lash Set $320.00
Spark Plugs $30.00
Coolant $20.00
Turbo Feed Line Washers $5.00
2 WRX Cam Seals $15.00
WRX Valve Cover Gaskets $22.00
Labor $250.00

Grand Total: $8,998.00

Total without Turbo Kit: $6,208.00

I would also like to mention that I had to modify the oil feed line that comes with the Perrin turbo kit in order for it to work with my WRX heads. You need to have the banjo fitting that is on your stock turbo feed line that connects to the head cut off and welded to the female end of the new feed line. I personally had a whole new line made using my old banjo fitting and it only set me back $35.00.

As I mentioned before I had a problem with my oil pan leaking. The leak was coming from the back area of the block, but before we knew this for sure we couldn't tell if it was the pan, the rear main seal or one of the piston access plates so we pulled the motor to find out. The reason I mention this again is because I ended up taking the Crower cams out and putting my stock cams back in when we pulled the motor to fix the leak. The Crower stage three cams were too aggressive for what I had in mind and I'm going to sell them and put a milder cam in later on. To make the Crowers work right, I would need a stand alone ECU or a reflash on top of my UTEC and that wasn't what I wanted to do at this time.

I fully intend on going further with this swap in the future, but I am limited right now because of a lack of funds. I understand that I am crazy/stupid to run my setup with a stock 5 speed tranny, etc., but I will upgrade these things in time. I am only looking to start with a ~375-400 HP tune and go from there. Please don't flame me for some of the shortcomings of my setup. I am completely aware of them and they will be fixed in the future.

So far I have only put 100 miles on the new motor and everything is great. I will post my progress with the break-in and my initial tune. Please feel free to ask me any questions.

Here are some pics:

Car
http://i12.photobucket.com/albums/a219/20Geezy/JessiesCamera187.jpg

Heads Before
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild090.jpg

Heads After
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild101.jpg

Valvetrain
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild104.jpg

Block
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild173.jpg

Turbo
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild116.jpg

Engine Bay
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild203.jpg

Engine Bay
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild196.jpg

I know that my intercooler piping looks like crap, but it's only temporary. I'm having all new piping fabbed soon.

NICE write-up! Way to well document everything for yourself and to share with us. Car is lookin good. Congrats on the project 'completion' and good luck.

Also, I bought the Subaru master gasket/seal kit with my subaru bucks... Guess I'll be getting some new valve cover gaskets since you said those don't work. Thanks for shedding that light. Just by looking at it, you can tell it has so many you'd never really use...

This is pretty
http://i12.photobucket.com/albums/a219/20Geezy/SubaruBuild173.jpg

Great write up good stuff, been through this myself over the last month :)

Mike

Nice write up man, I know what you mean when you say you have over extended your budget :p . Good luck with your set up.







-Z

For the spark plug hole gaskets... do they NEED to be for the WRX or can they be STI? Just double checking even though it's in your post.

For the spark plug hole gaskets... do they NEED to be for the WRX or can they be STI? Just double checking even though it's in your post.

They are all the same, even on the JDM heads.

what do you mean they were too aggressive???? my engine build is very similar to yours . with the stg 3 crower cams?? did the car not idle nicely? was it hard to start? what was it????

and?? on the 2.5 there is an extra breather tube coming out of the top rear of the block. where did you connect it?? or did you plug it? and yes i did realize that the sti gasket kit is a waste a money too. i dont recommend it either.

did you follow the ARP stud specs when you put the heads on?

Congradulations!!! Awesome write-up... I am in the midst of ordering my parts for the same job on my '02 and had actually posted the same question (misc parts other than turbo, sb, valvetrain, etc) a couple of day ago. I will be going with a TD06-20G and 264 cams though.

Also want to know about the extra breather tube.

In the service repair manual, they call for a cutting tool to remove the oil pan... Now it make sense. :)

Again, Congrats,
Tony

and?? on the 2.5 there is an extra breather tube coming out of the top rear of the block. where did you connect it?? or did you plug it? and yes i did realize that the sti gasket kit is a waste a money too. i dont recommend it either.

Yes, the car was hard to start, had a terrible idle and misfired like crazy. For the extra breather, I purchased a PCV cap from the auto parts store and capped it off.

did you follow the ARP stud specs when you put the heads on?

Yes, the instructions said to follow Subaru's torque sequence and to set the final torque at 72 ft/lbs. We started by using 24 ft/lbs, then 48 ft/lbs and then ended with 72 ft lbs.

Congrats man.....looks SICK! I can't wait to do mine.

Yes, the instructions said to follow Subaru's torque sequence and to set the final torque at 72 ft/lbs. We started by using 24 ft/lbs, then 48 ft/lbs and then ended with 72 ft lbs.
I'm urious as to this torquing process of ARP's. So for head studs 1 through 6... say you start at 1 (assuming order doesn't matter) and torque to 24, then 2 to 24 ft-lbs, so on and so forth until #6 is 24 ft-lbs. Then you start back at 1 and do the same process but to 48 ft-lbs. Then one more time to 72 ft-lbs.?

Yep. It makes sure the head goes on evently and straight so you don't warp them. Aluminum warps easily.

thanks for the info. mine is ready to drop in sometime this week.as soon as i tune it i'll see if i keep the crowers??

i fired up my engine and it idled like crap. but there is a trick that is applied from muscle cars. ( i own one ) when you run long duration cams you must drill a 1 to 2 mm hole in the throttle butterly to lessen the effect of the long cam. i drilled a hole in mine and it idles very nice and it also stopped the misfire codes. now i need to get it tuned up....

i fired up my engine and it idled like crap. but there is a trick that is applied from muscle cars. ( i own one ) when you run long duration cams you must drill a 1 to 2 mm hole in the throttle butterly to lessen the effect of the long cam. i drilled a hole in mine and it idles very nice and it also stopped the misfire codes. now i need to get it tuned up....

what duration cams are you using? 264? is this a fairly common trick with the Subees?

[EDIT: nevermind; i see that they're 272. think this'll be a problem with 264s?]

Question.

When you put the heads onto the block, did you do anything out of the ordinary or did you just reassemble them the way you disassembled them? Was there a need for anything more than that?

Question.

When you put the heads onto the block, did you do anything out of the ordinary or did you just reassemble them the way you disassembled them? Was there a need for anything more than that?

No, just make extra sure the block, heads, and head gaskets are extremely clean. If you are using ARP studs, lube them with the supplied oil/grease and hand tighten them into the block. Next, put on the head gaskets. Finally, lower each head on to the block and tighten them down per ARP's instructions.

[EDIT: nevermind; i see that they're 272. think this'll be a problem with 264s?]

No, there shouldn't be any problems with the 264s.

The only thing I saw was your disagreeance with purchasing the gasket kit.

if you can get one for 200 dollars, i would for SURE pick it up

theres so many parts in it, its not even funny

i added up the ones that just I used and it was well over 200

alex

No, there shouldn't be any problems with the 264s.

thx!

Tony

wow, sick!

Glad to see it up and running! I saw it at Suba and looks great now! (we were there when the fmic hose was in the way) Are you going to tune it with the utec or go with something else?

Glad to see it up and running! I saw it at Suba and looks great now! (we were there when the fmic hose was in the way) Are you going to tune it with the utec or go with something else?

Thanks! Yeah, I'm going to stick with the UTEC for now. I would love to switch to Autronic in the future though.

Update:

Got the motor broken in and went to the dyno for a basic tune. So far the new motor is running flawlessly. It had some piston slap for the first couple hundred miles, but is nearly stock sounding now. I dynoed on a Dyno Dynamics dyno @ 5280+ ASL (it was 100 degrees in the shop) and put down 300.5 HP and 291 TQ @ 16 psi. I'm still on 550cc injectors and they were maxed. I'm running a stock size MAF housing as well and we were seeing 4.9v. Looks like I need to slap on some bigger injectors and a big MAF housing. The car is definately faster than my old setup (2.0 block with a 20G @ 23psi) and I'm very happy with the results so far. With bigger injectors and MAF housing I should have no problem seeing 400+ HP with moderate boost. That is, if my stock 5 speed holds together. I will post a graph as soon as I can.


For comparison, a local STI with the same turbo kit put down 380 HP at 19 psi (on same dyno) with a couple more/different mods than I have. He was running a Magnus intake manifold, APS TGV deletes, PE 850cc injectors and a blow through MAF.

Hows that 20g spooling on that?

Very nice!

Hows that 20g spooling on that?

I saw full spool @ 4,000 rpms on the 2 litre, but never ran it on a 2.5.

Very nice!

Thanks!

post more pics of the engine bay! looks so damn sexy! i'm debating wether to go wtih the kingpin kit or the perrin pipe kit. (money doesnt matter) but the perrin kit in these pics doesnt look as hidden/low in the engine bay as most other people.

do you have a pic without the chargepipe on top of the turbo and the inlet pipe not connected? looks sexy bro, keep up the clean work!

good luck!
-alan

What cams do you have in there now? How high do you rev, or how high is the crower valvetrain good till?

I also vote for more pics :banana:







bigger pics if you can please :)

my god thats the most comprehensive write up ever done for a 2.5 swap - definitely bookmarked. Thanks man thats one sick wrx!

you've single handedly saved people hundreds of hours of asking and reasking the questions needed to swap the block.

--keith

Hey what are the Trq Specs you used for the ARP Head studs.. I was wondering myself?