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Discussion Starter · #1 ·
Sup fellow SubaFans... My car was being babysit-ted by a friend, when he took out for its month run. He told me UltraLord (My cars Name) was feeling a bit lazy and heavy... Few miles down he calls me say the UltraLord just shut down but he made a NASTY BANG,BANG, BANG... noise coming from the the bottom end right before it went dead.... Know the fact of the SPUN BEARING....

>>> I was woundering if any one has WITNESSED the replacement of a 2.5L(ej25) Shortblock on to the heads of a 2.0L(ej20)... Thanks you any feed back on the matter in hand..
 

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hmm...so, is the guy who was car-sitting still a friend? Did he mention he was redlining each gear?

What year is your car? If you were going to replace the motor why would you mix heads from different motors?
 

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Search Hybrid build, it's actually quite common.
 

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Discussion Starter · #5 ·
Its called a hybrid build... make sure the engine builder is good at what they do and make sure they use the 2.5 gaskets...
so was said friend beating on it? Or was it just an act of the Subaru gods?
It was actually a female dog for of better words... But i have been doing lots of research on the Hybrid part, and balancing out the options in cost and peace of mind... i was thinking of swaping it out for a EJ2.0TT but my question be, "Would i need to change the EMC (computer)?"
 

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It was actually a female dog for of better words... But i have been doing lots of research on the Hybrid part, and balancing out the options in cost and peace of mind... i was thinking of swaping it out for a EJ2.0TT but my question be, "Would i need to change the EMC (computer)?"
As in twin turbo? Yes you would need a new ECU and harness. You'd be better off with a hybrid build and a 18 or 20g turbo. Dont forget the trans though, that would need an upgrade too! The advantage to the hybrid is you keep the ECU and wiring harness, but get a stronger engine capable to handle quite a bit more power
 

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Discussion Starter · #7 ·
I have a 2005 (manf. 2004) suba WRX... lil mods.. Invidia exhaust (turb back).... Well going with the complete EJ25 shortblock (piston, rings, crank) brand spankin NEW is about 2K with shippin.... So if i am going to need a diff ecu for the EJ20TT (twinTurbo 250+HP) ENGINE that cost 2k with 30 to 40k miles on it... but the ecu must be up there... then the tranny... the short block is starting to sound like an A of spade.... But what about the heads... look here is the link to the shortblocks .... Subaru STI Short Engine asy TURBO fits 2002-2007 OEM - eBay (item 360293762936 end time Apr-22-11 07:11:04 PDT)
 

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Sorry but I'm unclear what you're actually asking.

I'd avoid a twin turbo.

You will need to remap your existing ECU if you are going to use any motor except the one you already have (the single turbo 2.0L). This means you will need mapping for a 2.5L.
 

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Discussion Starter · #9 ·
Sorry but I'm unclear what you're actually asking.

I'd avoid a twin turbo.

You will need to remap your existing ECU if you are going to use any motor except the one you already have (the single turbo 2.0L). This means you will need mapping for a 2.5L.
I am replacing my EJ20 shortblock (since it spun a bearing) with that of a EJ25... but i found a complete motor ealier which is a EJ20TT... but i guess i need a new ECU in order to make that work?... So i guess i am going to go with the EJ25 shortblock better...
 

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a lot of twin turbo cars end up as single turbo cars later in life because a single turbo is less complicated and reliably makes more power. The twin setup might be a fun project but be prepared for more wrenching than driving. Just my 2c .. but being around the turbo car world since the early 90s.. I've seen what works and what .. well.. doesn't work as well as one would think it should.
 

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Discussion Starter · #11 ·
Yeah, RELIBILITY is the key... that is why i chose to go with the replacing my EJ20 short block with that of a EJ25... I hear the heads fit it..
 

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So i guess i am going to go with the EJ25 shortblock better...
This would be my choice also. However, you will still need to remap your existing ECU in order to run a hybrid motor (or any 2.5L for that matter).
 

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The only problem with running a hybrid is that you have to run e85 or another high octane fuel because of the compression ratio. That or really low boost. (that is what i was told at least from shane and DB)
 

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I have a MOD mappin sys connected to the ecu... or would i have to do any diffrent way...
Sorry I'm unfamiliar with the system.

The only problem with running a hybrid is that you have to run e85 or another high octane fuel because of the compression ratio. That or really low boost. (that is what i was told at least from shane and DB)
The compression ratio can be controlled with sealing choices, machining, or both prior to assembly.
 

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Why lower boost if the shortblock is from a EJ25... I would think i can go with a bigger boost?
The implication was that you would end up with an increased compression ratio, necessitating lower boost overall.

When you say "EJ25" you are including (at least?) four motors. The ones of interest to you are the EJ255 and EJ257. Research those two motors before making decisions. Also research hybrid motors thoroughly, including what supporting modifications you will require.
 

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Ultralord? Um I don't know what to say to that.... :tongue:

I just like calling my cars by a girl's name, preferably the last fine looking woman I had the pleasure of having quality time with if you know what I mean.....
 
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