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Old 10-29-2020, 08:59 PM   #1
Jp925
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Default 06 WRx short block in Sti

I have a buddy who blew his motor and another buddy who has a healthy EJ25 short block he pulled from his WRX when he built a new motor. I know this has been covered countless times with WRX guys who want to run the Sti heads, but is there any harm in an STi doing this? can the slight compression difference be compensated using RomRaider? obviously this isn't a permeant solution, but can this work to DD until he has money for the proper rebuild?

To clarify, I want to run an 06 wrx short block, with my 06 STi heads in an 06 STi.
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Last edited by Jp925; 10-30-2020 at 11:47 AM.
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Old 10-30-2020, 11:12 AM   #2
Samurai Jack
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Don't really understand the question.

What are you asking:
- Can you run STi heads on an STi motor? Of course.
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Old 10-30-2020, 11:45 AM   #3
Jp925
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I want to take the short block from an 06 wrx and install it into my 06 STi paired with the heads from my 06 STi.
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Old 10-30-2020, 12:18 PM   #4
Samurai Jack
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That would not be a problem.
As long as your heads are healthy, and the short block is healthy, you should be OK.

How many miles on your heads?
You may require a rebuild of the heads.

You would just have to re-tune everything due to the swap. You can't just bolt them together and expect not to re-tune.
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Old 10-30-2020, 12:19 PM   #5
BlackFighter
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Its called a hybrid, people have been ding it for ever. Do some research on this forum and you will see lots of info. They might even be its own section. Will def need a retune and maybe some supporting mods but not sure.
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Old 10-30-2020, 12:26 PM   #6
Jp925
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I donít think this is a hybrid swap though, the 06/07 short block is an ej255 2.5l. From doing the deep dive into this everyone says these blocks are identical aside from piston shape, thus resulting in a very slight compression ratio difference.

I was going to have the heads rebuilt, but I had planned to bolt and go on the short block. Short block was pulled at 80k, so it should be fine for a year or 2.
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Old 10-30-2020, 11:09 PM   #7
Jp925
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Quote:
Originally Posted by Samurai Jack View Post
That would not be a problem.
As long as your heads are healthy, and the short block is healthy, you should be OK.

How many miles on your heads?
You may require a rebuild of the heads.

You would just have to re-tune everything due to the swap. You can't just bolt them together and expect not to re-tune.
I plan to rebuild the heads, motor has 60k
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Old 11-03-2020, 03:10 PM   #8
Jp925
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Quote:
Originally Posted by Samurai Jack View Post
That would not be a problem.
As long as your heads are healthy, and the short block is healthy, you should be OK.

How many miles on your heads?
You may require a rebuild of the heads.

You would just have to re-tune everything due to the swap. You can't just bolt them together and expect not to re-tune.
is this something tunable with Rom Raider?
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Old 11-04-2020, 11:02 AM   #9
Samurai Jack
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Quote:
Originally Posted by Jp925 View Post
is this something tunable with Rom Raider?
https://www.romraider.com/
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