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Old 12-17-2018, 08:18 PM   #1
aaronnichols
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Default Can I install a 2015 ej 25 sti short block in my 04 rs impreza?

Hello again. Just found a great deal on a 2015 sti short block and would like to install on my 04 rs impreza and i have just a few questions.

First will it bolt to my 04 bell housing?

Also can i bolt my heads back on it or should i upgrade the head/valves.

Also can i use the old injectors or should i upgrade?

Should i upgrade the fuel pump if i go with bigger injectors? What injectors do you recommend?
Thanks!
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Old 12-17-2018, 08:37 PM   #2
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Yes.





All of those things are a bad idea.
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Old 12-17-2018, 08:41 PM   #3
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Yes.





All of those things are a bad idea.
Can you elaborate?
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Old 12-17-2018, 08:48 PM   #4
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It will bolt in just fine but you'll have a much lower compression ratio, so less power, really sluggish response, and more fuel won't do anything to improve that.
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Old 12-17-2018, 09:00 PM   #5
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It will bolt in just fine but you'll have a much lower compression ratio, so less power, really sluggish response, and more fuel won't do anything to improve that.
Why is it not sluggish in the 2015 STI? Whats different about the cars? Thanks
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Old 12-17-2018, 09:25 PM   #6
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Quote:
Originally Posted by aaronnichols View Post
Why is it not sluggish in the 2015 STI? Whats different about the cars? Thanks
Turbo vs. NA. Low compression turbo SB will suck running as a NA.
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Old 12-17-2018, 09:28 PM   #7
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Turbo vs. NA. Low compression turbo SB will suck running as a NA.
Nice. So what you guys are saying is slap a 24psi turbo and im good to go?
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Old 12-17-2018, 09:37 PM   #8
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Okay at this point your just throwing stuff at a wall and hoping something sticks... start with a wrx or sti platform and go from there, i dont get what is up with you and sti swapping your 2.5rs, its a bad idea. Itll take way more effort than it is worth. Just dont...
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Old 12-17-2018, 09:50 PM   #9
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Do what is required to get your car running well, and forget about swapping it, making 800hp, or whatever else. If you want a turbo subaru, you need to just sell it and buy one. If you can't afford to do that, you probably can't afford to make one yourself.

In the meantime, I'd suggest doing some reading about how turbochargers, and engines in general, work.
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Old 12-17-2018, 09:52 PM   #10
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Okay at this point your just throwing stuff at a wall and hoping something sticks... start with a wrx or sti platform and go from there, i dont get what is up with you and sti swapping your 2.5rs, its a bad idea. Itll take way more effort than it is worth. Just dont...

the whole reason for buying an RS was to throw stuff at walls. Lol Im sure ill need to Add better brakes, drive shaft, transmission, rear differentials as well but i think if i take it easy for now it should be fine.

What would be the bare minimal i would need to make it work if i took it easy. 🤔
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Old 12-17-2018, 10:08 PM   #11
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Quote:
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Can you elaborate?


Option 1 - Too lazy to do the research that has been listed 1000x times before ,specifically on this forum
Option 2 - Trolling
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Old 12-17-2018, 10:41 PM   #12
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Option 1 - Too lazy to do the research that has been listed 1000x times before ,specifically on this forum
Option 2 - Trolling

Sorry, i didnt find the thread that shows me how to upgrade my 04 rs to a 450 whp sti 1000x can you link at least one? 😂

Last edited by aaronnichols; 12-17-2018 at 10:47 PM.
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Old 12-17-2018, 10:43 PM   #13
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Trrolll x10000
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Old 12-17-2018, 10:48 PM   #14
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Trrolll x10000
When did asking sincere questions on a subi forum become trolling? Wow the toxicity with some of you is unreal.
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Old 12-17-2018, 10:54 PM   #15
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I do appreciate jamal and that one other guy for offering actual help. Thanks you two! Oh also is there another subi forum? Cause Im looking around now. 🤔
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Old 12-17-2018, 11:05 PM   #16
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You already have at least one thread about this where a lot of this was already covered/ So why are you starting another one asking basically the same thing all over again?

There's a good reason basically no one has ever bothered with an 04 impreza when there's a wrx and sti version of the same car. You can buy an 04 wrx for like $3k these days and even that would be a much, much better starting point.
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Old 12-18-2018, 03:05 AM   #17
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Don't ever put a na 2.5 SOHC on a DOCH 2.5 STI engine. You're defiantly better off buying a long block not short block. Lots of JDM front clips for sale that will include complete engine, ecu, engine/chassis harness. This is your cheapest option and a lot of the times you can get a complete STI drivetrain (6 speed ,R180 and brembos) with it. Shop around and you can get good deals.
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Old 12-18-2018, 06:55 AM   #18
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Don't ever put a na 2.5 SOHC on a DOCH 2.5 STI engine. You're defiantly better off buying a long block not short block. Lots of JDM front clips for sale that will include complete engine, ecu, engine/chassis harness. This is your cheapest option and a lot of the times you can get a complete STI drivetrain (6 speed ,R180 and brembos) with it. Shop around and you can get good deals.

Ok so my sohc headers are a problem. Ive been shopping around and this is the best deal i could find. 2015 15k miles perfectly working engine only $800 sti. So ill just shop around for the headers and pop em in. Next ill grab a lo boost turbo, and work my way up to drive train and ecu wire harness.
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Old 12-18-2018, 11:37 AM   #19
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Quote:
Originally Posted by aaronnichols View Post
Ok so my sohc headers are a problem. Ive been shopping around and this is the best deal i could find. 2015 15k miles perfectly working engine only $800 sti. So ill just shop around for the headers and pop em in. Next ill grab a lo boost turbo, and work my way up to drive train and ecu wire harness.
Good luck
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Old 12-18-2018, 07:04 PM   #20
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I love how all you guys always say “you would be better off buying or doing a different way” lol I bought the car with a specific project in mind. I chose to do it a certain way. If you dont have anything good to say or helpfull information that enables, or teaches a beginner how to go about doing it in his way then why say anything at all. So if anyone can guide in upgrading my rs into a performance sti then by all means speak up but if your here to troll or offer remarks that dont help then just avoid my threads. Im sure the subi enthusiast wh are looking for information regarding the topic would appreciate it.
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Old 12-18-2018, 07:57 PM   #21
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Quote:
Originally Posted by aaronnichols View Post
I love how all you guys always say “you would be better off buying or doing a different way” lol I bought the car with a specific project in mind. I chose to do it a certain way. If you dont have anything good to say or helpfull information that enables, or teaches a beginner how to go about doing it in his way then why say anything at all. So if anyone can guide in upgrading my rs into a performance sti then by all means speak up but if your here to troll or offer remarks that dont help then just avoid my threads. Im sure the subi enthusiast wh are looking for information regarding the topic would appreciate it.
You don't seem to be listening. what you are doing is a bad idea. several people who know way more than you are giving you ideas and you are ignoring it. there is nothing special about the sti shortblock. if you use it with 2.5 rs single cam heads you are waisting your time. so you go ahead and do what your gonna do.
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Old 12-18-2018, 09:28 PM   #22
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Please stop feeding the trolls
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Old 12-29-2018, 10:06 PM   #23
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You don't seem to be listening. what you are doing is a bad idea. several people who know way more than you are giving you ideas and you are ignoring it. there is nothing special about the sti shortblock. if you use it with 2.5 rs single cam heads you are waisting your time. so you go ahead and do what your gonna do.
Yes i already got that part. After all the trolls just flamed me a gazillion times Some kind soul finally told me why it was a bad idea. Im still going to upgrade this rs. But i might as well just buy a IAG block already built with heads to match the hp im looking to achieve. Its still a great deal on the STI short block. $800 for 10k miles nothing wrong and it 2015 model.
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Old 01-18-2019, 10:59 PM   #24
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Quote:
Originally Posted by aaronnichols View Post
Yes i already got that part. After all the trolls just flamed me a gazillion times Some kind soul finally told me why it was a bad idea. Im still going to upgrade this rs. But i might as well just buy a IAG block already built with heads to match the hp im looking to achieve. Its still a great deal on the STI short block. $800 for 10k miles nothing wrong and it 2015 model.
I personally find RWD converted RS with a decent NA power build (180ish whp) to be pretty nice. But that's just me.
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