Skip to content
View in the app

A better way to browse. Learn more.

Ultimate Subaru Message Board

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

EJ22T + 2.5 SOHC heads..(simple/short/not stupid questions)

Featured Replies

Hey there all, I've been looking around forum for no joke 20'ish hours and I really just need to ask a couple of small questions...

 

I was thinking about getting an 2.5 SOHC head/intake set for my EJ22T 91 Legacy.

 

My questions are.....

 

1)The oil/coolant issue...

 

So for the coolant you just bypass the block+head and just tap into the lines appropiately.

 

The oil you just use a plug on the top towards the back.

Just that simple or I'm missing something?

 

2)Low compression......

 

Are numbers in the low 7's ok? Can I switch to a thinner head gasket to bump it up a bit (I figure theres more clearance then the DOHC)

 

3)Up-pipe issue....

 

I'm leaning towards grinding a small part of my heads because it seems a lot easier then fabing up the up-pipe....why not?

 

4)Phase I and Phase II...

 

whats the difference? Will it matter to me?

 

5)Other problems I don't know about...I'm going to have to mount an intercooler somewhere...not sure where? Anything else....

 

Thanks so much - Jutboy

 

PS> Feel free to instant message me!

  • Author

your right....I mean the 2.5 heads

  • Author

I just was told that I have a feed line for oil in my block (no one would have a pic would they???) and then I need to weld a return line into my oil pan....sounds good....coolant is just tapping in existing lines.

 

Sounds right?

This is usually done with dohc ej25 heads. And there shouldn't be any issue with the uppipe or downpipe that I'm aware of.

 

Its been gone over in detail on www.legacycentral.org as well.

From my reading...there is a clearance issue using an OEM up pipe with EJ25 SOHC heads. No issue with DOHC heads...but if you have them (SOHC) already, no sense in buying more parts. Do the clearancing you need and go.

 

The low compression is going to mean slow spooling. That's pretty low, even for a turbo motor....A thinner HG isn't going to bring it up by much and decking the heads plus the thing gasket might bring you more problems with cam timing than the compression will help.

 

I can't be absolutely sure on the oil tapping point on the block but I know of others who have Tee'd off the pressure sender or used another port on the other end of the block. A simple drainback into the pan is sufficient although I can't believe people try and sell banjo bolts to double as a return line/oil drain plug....

 

Any particular reason why you want to go with the EJ25 heads on the EJ22 block?

 

Jay Storm

  • Author

They flow really well...lets you take advantage of a bigger turbo.

They flow really well...lets you take advantage of a bigger turbo.
The replies you've gotten over on nasioc describe what I have also learned. Personally, I think the better option would be WRX heads on the EJ22T block or new pistons. With such low compression and a huge turbo, you'll be needing to stay in boost much more often for a daily driver.

 

Just my opinion though...YMMV.

 

Jay Storm

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.