EJ22T w/ EJ25 heads?

[BAC5.2]

How direct of a bolt on is this?

Use some N/A DOHC Phase1 EJ25 heads on my EJ22T shortblock.

How well do these heads flow compared to the stock heads? How strong are the heads compared to the EJ22T heads? Would I have to go to standalone engine management if I went this route, or could I run the engine in DOHC form with the stock engine management?

I am just trying to plan out this project (if I decide to undertake it).

Thanks guys, I know there are some topics on this, but I want to stirr a new topic so any new info can be surfaced.

Thanks!

[Legacy777]

http://bbs.legacycentral.org/viewtopic. ... +head+swap
http://bbs.legacycentral.org/viewtopic. ... +head+swap

I think there's a few more you can find if you search, but those are the pertinant ones.

[morgie]

i think the issue with those heads would be oil feed / return + coolant feed ?

[vrg3]

http://www.legacycentral.org/library/headswap.htm

[aspect]

The link posted above is for the phase II heads, btw.

Most of my information about these heads comes from mark ramirez, who made a post on nasioc a while ago telling people about how good this combination really was. (http://forums.nasioc.com/forums/showthr ... genumber=1 scroll down about half way...)

I don't think you'll need any extra engine management, and the installation is apparently very simple. Apart from possible oil line issues like morgie mentioned, I don't know of any problems bolting these on.

I'll copy and paste some exerpts from an email conversation I had with Mark.

<email>


> I'm building a rally engine, based on the stock
> motor in my 91 turbo legacy. The two major goals for
> this engine are reliability and a nice responsive
> mid-range power curve, in that order. From what I've
> read, the dohc 2.5RS heads are not exactly a bolt-on
> part, but do offer good low-end power and are
> readily available. I have also tracked down sellers
> for 98 JDM WRX heads, and 97 JDM Legacy Twinturbo
> heads.
>
> If you were shooting for quick engine response and
> midrange power instead of 400whp, what would you go
> with for a head setup? It seems like a 8:1 CR would
> be a good idea.

Heads: It seems there are a million different JDM
wrx/legacy/sti head options. I use the phase 1 dohc
heads (98 RS, 97-99 2.5 legacy/forester) for two main
reasons: 1. I can get parts and service these heads
easily because they are domestically available, and 2.
they flow really well and can rev high and perform
quite fine. Yes, there are heads out there that are
slightly better, but the gains are really only
noticeable on top end big turbo high air volume
applications. For your criteria, the 98RS heads will
have the port size which will optimize your low and
mid range requirements, will be very reliable if
properly tuned, and very serviceable.

> As for internals, my current plan calls for stock
> turbo legacy crank, some nice forged pistons with
> ceramic coated tops to minimize any possibility of
> detonation, and probably stock rods. Engine
> management is still totally up in the air, but
> something very standalone like AEM or FJO.

Pistons: you won't need ceramic coating. Stock units
are fine. Detonation won't be an issue, especially if
you are running 8:1 comp ratio. Also, the piston oil
squirters on ej22ts keep the pistons plenty cool.

Final recommendation:
1. phase 1 dohc heads (98 rs), stock cams,stock
springs
2. thin 2.2 head gaskets (available on 2001 2.2 liter
impreza) to maintain 8:1 comp ratio
3. 16G turbo
4. stock ej22t block
5. good engine management


</email>

[Shane]

^^^What boost could that setup handle on a daily basis?
What is the MAX boost you would want to run with that setup?
Any links to someone that is running that setup right now?

$800 for the EJ20T complete head, turbo and Intercooler from a 1999 WRX...Good price?