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Discussion Starter #1
hey guys :D
I think I'm done with the Na world, and it's time to move on to the other world :D
I have a new/spare EJ253 shortblock and I will build that block so it can handle +15 psi for my DD purpose. For some time I will run it @ 6 psi until I get enough $$ for the fuel system (AFAIK oe rs fuel system can't go above 6 psi) anyway, here is my block parts list:
- New EJ257 pistons, pins, and pistons rings.
- New Brian crower econo rods (I already have those).
- Stock EJ253 crank shaft and bearings.

I already have my heads P&P with delta 2000 grinds cams, and will get a free lupespeed turbo kit from a friend who got an STi last year.
What do you guys think about this setup? Will run it @ 6 psi for some time till I get the fuel systme sorted out for 15 psi ;)

oh yes, my car is 03 RS with map system and it's rwd (I have JDM R180 rear end)
 

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2009 Legacy GT
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513 Posts
Well while you are at it I would get a EJ257 Crank, and the head gaskets instead of the EJ253 crank. For fuel a high lph pump isnt that expensive you would only need to update your injectors and rails. What engine management will you use?

You should also thing about keeping the EJ253 intact and running the turbo kit at 6psi for a while ive ridden in a 03 RS with the AVO kit at 6 psi on the stock motor and that thing pulled. The owner said he had the desire to start at 6 and move to 16 ( generally speaking) but was so happy with the 6psi and the results he never did.

Sounds good either way keep good notes
 

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MY99 GF4 EJ227 JDM 6spd
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why stay with stock Ej257 pistons when you can go forged and not worry about ringlands?

Get some forged pistons, STi rods, and put that with your crank. Now with that setup being lower CR than before, You can run your 6psi just fine. Just change out to bigger injectors, then you're all good to go. OR add an FMU, which is simple.

But really when you start gettin into the turbo stuff, and wanting 300whp and stuff like that, this will NO LONGER be a budget build like how "most" want to stay. Simple stuff would be a direct WRX swap over to yours and stg2 with 16G or HTA68 and be with it. hahaha
 

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Discussion Starter #4
Well while you are at it I would get a EJ257 Crank, and the head gaskets instead of the EJ253 crank. For fuel a high lph pump isnt that expensive you would only need to update your injectors and rails. What engine management will you use?

You should also thing about keeping the EJ253 intact and running the turbo kit at 6psi for a while ive ridden in a 03 RS with the AVO kit at 6 psi on the stock motor and that thing pulled. The owner said he had the desire to start at 6 and move to 16 ( generally speaking) but was so happy with the 6psi and the results he never did.

Sounds good either way keep good notes
I would like to get upgraded fuel pump and injectors, but currnetly I'm on budget. Yeh head kaskets are on my to do list for the 6 psi, I don't like the idea of changing them after a while for higher boost :D
oh and about the injectors, I made some search and came up with an o-rings kit that make you able to use wrx injectors? how good are they for 15 psi (I don't have any plan to go higher than 15 psi)
I know the STi crank is much stronger, but why change my new ej253 crank if I'm not going to make over 250whp?

why stay with stock Ej257 pistons when you can go forged and not worry about ringlands?

Get some forged pistons, STi rods, and put that with your crank. Now with that setup being lower CR than before, You can run your 6psi just fine. Just change out to bigger injectors, then you're all good to go. OR add an FMU, which is simple.

But really when you start gettin into the turbo stuff, and wanting 300whp and stuff like that, this will NO LONGER be a budget build like how "most" want to stay. Simple stuff would be a direct WRX swap over to yours and stg2 with 16G or HTA68 and be with it. hahaha
I love to get forged pistons, but I'm on budget. Sti pistons are cheap and can handle 20 psi so easy, they will lower CR too.
about the rods, what's wrong with Brian crower rods?

I'm not looking for 300whp, I guess at 15 psi I will mostly make ~250whp? right? I've been living with my 160hp impreza for years, and I guess 250whp will make me happy for years too :D
 

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MY00 //// BRP 2.5RS coupe
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fuel pumps are cheap and stock 06+wrx or sti injectors should be good enough, rather not cheap out on that

you are going to the extent of cracking the motor apart i wouldn't go cheap on some things if you know what i mean =]
 

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2002 Aspen White WRX
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There's no reason to buy a crank. They're all forged.

Make sure you get aclutch that'll hold the power. You could run your stock injectors for a little boost but, not a whole lot. IIRC, the factory tune maxs the stock injectors out at like 80% duty cycle. So there is a little bit of room but, I would suggest you just buy injectors. Better safe than sorry. I would HIGHLY recommend that you dont halfass it when it comes to EM, it controls how everything and that's very critical when boosting an N/A setup.
 

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1990 legacy wagon
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Get some STI rods instead of the BC rods. Cheaper and good for 400whp. Then you have money left over for a Walbro fuel pump.
 

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2006 2.5i San Remo Red SC
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don't know how old this thread is but STI,wrx, and impreza share the same crank, the ej253 rods are also forged its the pistons with out a good tune that get damaged. you can go to 9 psi supercharged boost at least safely on stock block with a very good tune. you can also just get forged 10:1 pistons like the stocks and not have to run high boost, something like 14psi like wrx stock boost is like 18 psi of boost but since torque will still be there you don't have to go up in boost when you have stock compression with forged pistons. 2.5i fuel system with injectors and pump is good for 15 psi of fuel demand and flow..regulator is the same as wrx from what I hear. The most important thing is engine management tune tune tune!!!
 

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2002 Aspen White WRX
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Get some STI rods instead of the BC rods. Cheaper and good for 400whp. Then you have money left over for a Walbro fuel pump.
It's all in the tune, but yes STi rods are forged. They're cheap as dirt too.
 

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2003 Subaru Forester Black/Gra
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don't know how old this thread is but STI,wrx, and impreza share the same crank, the ej253 rods are also forged its the pistons with out a good tune that get damaged. you can go to 9 psi supercharged boost at least safely on stock block with a very good tune. you can also just get forged 10:1 pistons like the stocks and not have to run high boost, something like 14psi like wrx stock boost is like 18 psi of boost but since torque will still be there you don't have to go up in boost when you have stock compression with forged pistons. 2.5i fuel system with injectors and pump is good for 15 psi of fuel demand and flow..regulator is the same as wrx from what I hear. The most important thing is engine management tune tune tune!!!
Sorry but stock Injectors won't work with 15 psi, you will need larger ones
 

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So if you were going big on a EJ253 what would be the way to go.

Build EJ253 block, is it even worth it? A brand new stock EJ257 is 1800 bucks.
Even with forged pistons, EJ253 is still open deck.

How much is it going to cost to get the EJ253 able to handle 300 HP?

Application is a supercharged EJ253, don't want to blow it up, but build it to handle say 240 WHP - 300+ crank horsepower.

The most likely choice to me seems like bone stock EJ257 short block and EJ253 heads and accessories and ECU?
1800 bucks for the short block. I'd love to put in forged pistons but it's another 500 minimum, although then you could put in 9.8:1 pistons...?
 

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2000 Forester
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Open deck motor-
You have less room for error, but "open deck" doesn't mean your motor is a ticking time bomb. It's all in the tune.

When I was first doing research to turbo my motor, I saw that a lot of paranoia was in the air in the early 2000's with people worried about their open deck motors. When posing questions about "boost + open deck" people would say "it can't be done, just go sell your car and buy a WRX".

This site and the countless members are definitely proof of the fact that, that's not the case.
I wouldn't worry about your block, especially if you're planning to build your motor.

I'm not sure what tuning options your ECU has, but if there's no open source tuning available for it, you can always use Emanage. :projectsti.com:
 

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All good with tuning. Currently running stock ECU - we've uncovered some useful parameters in the ROM like rear O2 sensor fuel trims (turned off) and engine load limit (raised).

So I guess I need to figure out where this is going. I think my Supercharger maxes out around 11 PSI which would be around 240 WHP (assuming staying near 9.8 or 10:1 CR) 320-340 crank HP. What it takes to reliably support that power... Opendeck EJ253 I've heard is an issue beyond 10 PSI but how much work and/or money is it worth putting into a engine that is only 320 or 340 HP.
 

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All good with tuning. Currently running stock ECU - we've uncovered some useful parameters in the ROM like rear O2 sensor fuel trims (turned off) and engine load limit (raised).

So I guess I need to figure out where this is going. I think my Supercharger maxes out around 11 PSI which would be around 240 WHP (assuming staying near 9.8 or 10:1 CR) 320-340 crank HP. What it takes to reliably support that power... Opendeck EJ253 I've heard is an issue beyond 10 PSI but how much work and/or money is it worth putting into a engine that is only 320 or 340 HP.
05Outback, sorry for the late response, but I think this thread might be worth your time. http://www.rs25.com/forums/f7/t39629-boosted-ej25d.html

It's really up to you how much money you want to put into your car. I think being able to spank 2.0L WRX's and keep up with STIs is a pretty good feat for a daily driver for the cost of maybe only $1200 in parts (I'm turboing my car). If you want to spend a little more money, the thread above is proof that "open deck" really doesn't mean anything with some internals.
 

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Thanks

Yes I think I should just put stock STI Rods and stock STI pistons in my Stock EJ253 block. I found out that my supercharger will only go up to 11 psi though.

Still quite a bit of labor just to get it rebuilt with stock STI rods/pistons, probably a couple or 3 thousand bucks R&R'd if I do not do any work myself. But gets me a "like new" engine.
 

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2001 SRP 2.5RS/RA/SOHC Monster
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An OEM 257 shorty can be had for $16-1800 Brand new, not sure it would be worth it.
 

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2001 SRP 2.5RS/RA/SOHC Monster
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Yes, there is more to be done,but it can definitely be done within the 3k you are quoting for yourself.
 

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New 257 on my intake, heads, etc. installed for 3000 bucks, do you think?
I just did the headgaskets and timing belt unfortunately, so a lot of stuff could be reused, like water pump, timing belt.


I have never pulled an EJ let alone built up a long block but maybe I Can do it. If it was just parts, no labor, it'd be closer to $2000 I bet.
 
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