I have a question for every impreza fans.

The 2002 Impreza WRX's EJ20 is more durable or the 04+(EJ25) is more durable ?
and what's different between Spec C EJ20 and US EJ20? I heard the Spec C's engine is totally different from the US EJ20, higher RPM, more powerful, and fast reaction.
I personally like EJ20 then EJ25 because I think EJ25 is too heavy. Therefore, not good on corner.

 

Here's a good place to start http://www.spdusa.com/wrx_intro.htm

 

Research these engine models for the Impreza:

EJ205 (US WRX 02-05)
Although it's strong, it's probably the least impresive of the 4 engines. Designed for the world market WRX models, but no variable valve timing.

EJ207 (JDM WRX '99-01; JDM WRX STi '98-present)
Very sought after for it's 8K RPM limit, forged internals, valve timing, DOHC, etc.

EJ255 (US WRX '06-present)
Another very strong block with more displacement and low end torque than the EJ205. It replaced the EJ205 and also comes with DOHC.

EJ257 (US WRX STi '04-present)
Same block design as the EJ255, but different internals and heads. Very stout engine and holds up to over 500whp on stock block and stock internals and is friendlier to the bigger turbos than the 2.0liter versions due to the extra displacement.

There's more to it than that, but I just wanted to go over some of the basics. I didn't include the EJ22K used in the holy grail of Imprezas, the WRX STi 22B. They're all great engines. Some have their shortcomings, but there's really nothing "negative" about any of them in regards to performance and reliability.

 

Thank you for your infomation. But I have other questions that~
How much horsepower does the EJ205 can stand? If I want to change a big turbo, should I change the internal parts? Moreover, sometimes I feel my transmission is not following to my engine. I mean the reaction is too slow......is that ture? or just my feeling is not right?

 

Thanks man, this website is really helpful~ I print out all the information I need. Ready for take some time to study for it.

 

300 for the ej205

ej207 > ej22 turbo motor > ej257

 

I'm not sure what you mean by you tranny not following your engine.

But the EJ205 can handle plenty of power with stock internals, somewhere in the ~350whp realm, it's not an exact science. It all depends on how you treat the car.

However, your tranny is only good for around ~260-280whp. After that it becomes iffy. Once you go beyond that power level, it would be in your best interest to upgrade the gears.

But, ultimately, your title asks which is better between the EJ20 and the EJ25... the EJ25. Bigger is better in this particular case.

 

hmmmm

 

Good catch, not sure why I put that. I wanted to write that it had no variable valve timing.

*Fixed

 

yea i heard that the ej20 is supposedly better because of open loop system? somethin bout fuel i believe...n also that it takes mods without fuel management a little better then 04+

 

open loop is ECU stuff

Superglue WRX
i was gonna go home tonight and pull the timing cover off my car hehe

 

oic...thanks for clearing it up...so im assuming it might be easier to tune a 02

 

Yeas, but that's totally ECU related. The 02-05 EJ205 engines are identical, the ECUs are not. The problem in the 04-05 ECUs is in switching maps. They use one map for Partial Throttle (open loop**), and one map for Wide Open Throttle (closed loop**). There is a significant time delay when it switches between maps. This results in a temporary, yet unhealthy, lean condition in the engine. This can theoretically lead to engine misfires, or worse. Getting an engine management system should be the first thing on an 04-05 owners list if they plan on driving the car hard.

** I may have the open and closed loops labeled backwards, but it's not important. I just wanted to demonstrate what is happening in the ECU. Just one more reason to get a Bugeye!!!

 

thats some good info. i have a 05wrx and i want to know more about the difference in our ECU thats making us slower than bugeyes. you got any more info or links? thatll be great help.

 

Here's some OL/CL info that I found on Nabisco....

http://forums.nasioc.com/forums/showthread.php?t=671294

http://forums.nasioc.com/forums/show...hlight=OL%2FCL

Cheers!