View Full Version : turbocharging a EJ25 engine

13th February 2001, 20:25
I know that there are some 22b members that already have some experience turbocharging the EJ25 engine...
In order to fit it in a WRX (euro spec 98 car) is it a matter of just swaping the short engine. By this i mean changing the EJ20 short engine with a EJ25 engine and still use the EJ20:
exhaust manifold
intake manifold
injectors (or maybe bigger ones....)
engine mounts
turbocharger (EJ25 engine internales should be able to handle a max of 12psi)


13th February 2001, 20:48
Not sure if the heads will bolt straight on or not. It may be worth you while getting the Phase I EJ25 DOHC heads... the Phase II are SOHC designs http://bbs.22b.com/ubb/frown.gif Might be worth having a chat with Cobb Tuning in the states who have done a lot with the EJ25... closer to "home", J has been looking closely at the EJ25 and may be able to shed some more light on the subject http://bbs.22b.com/ubb/smile.gif



13th February 2001, 21:40
Cobb tunning.....any web page???


13th February 2001, 22:10
Here you are carlos,


13th February 2001, 23:13
There are quite a few differences and combinations... but as per usual.. nothing will bolt up... the manifold will foul..

The 2.5 manifold wont bolt upto the 2.0 heads... the intercooler wont fit with the 2.5 engine fitted...

There are a few things that need to be done.

2.0 heads need to be machined... the crank is different and so are the rods...


14th February 2001, 00:19
uhmmmm.......doesn´t seem like an easy job, specially if the stock WRX intercooler won´t fit with the EJ25 engine.
Although i think the stock heads of the EJ25 are good for upto 350 hp. And if we keep the stock internals (or change them with for example the JUN 2.5L turbo kit)and intake manifold the only pieces that would need to be made would the exhaust manifold, and a custom made TMIC.

BTW Cobb Tunning says that the PHASE II EJ25 is better for turbocharging than the Phase I, but the DOHC heads of the Phase I are better than the SOHC heads of the Phase II......

At the end, it seems to be as expensive as a 350hp EJ20 engine.


23rd February 2001, 04:49
Actually, you might consider using the 2.2l block used in the US spec Legacy turbo (1992-1994, part # 10103aa310) as it apparently is much more compatible. I'm not 100% sure that it is a bolt on affair, but from what I can tell it is.

Also, here's someone who might shed some more light on the subject:

and his web site

Hope this helps.

[This message has been edited by RS25.com (edited 23 February 2001).]