EJ20 better or EJ25

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10-26-2006, 04:27 PM

#16

sigma pi

9 to 5 mod

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Car Info: 03 Impreza WRX

Quote:

Originally Posted by Superglue WRX

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!!!

and tehy look better

10-26-2006, 04:47 PM

#17

MO REX

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Car Info: 02 PSM WRX

Quote:

Originally Posted by Superglue WRX

Your explination is correct but you do have it backwards.

10-29-2006, 10:39 AM

#18

Krinkov

Yeah, You've Probably Never Heard Of Me.

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Quote:

Originally Posted by kansai_wrx

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.

EJ20-25 are built off the same block and weight the same, so if thats the only thing holding you back then by all means get the 2.5

US EJ20s are at he bottom ofthe food chain of EJ20s, you would have to get a JDM one to get the same forged rods/crank/semi-closed deck that come stock in the US STI shortblock. I dont know what you goals are, but Ive owned both 2.0 WRX and an STI and the 2.5 is a much better choice for a street car, theres no question about it. And I would even take the US sti 2.5 over the JDM 2.0s unless I planed to run my car on pump gas all the time, they run 9.0+ compression on those, the ones I have seen trying to run on pump gas here in CA have actually gotten worse results than US 2.0s using the same turbos since the US have enough compression headroom to use mor eboost, the JDM ones are just too high to get alot of boost on unless you constantly run good gas