I have been trying to find exactly what the difference between phase I and phase II motors are. can someone please help me. i have searched here and on nasioc but i cant find it put in a clear way.

 

Essentially....

Phase I= first gen motor, weaker, less thought put into it.

Phase II= stronger, built better and will last longer


But there's always an on going debate.

Phase I frankie ftw

 

is there a specific year that subaru switch to phase II? is there anyway to tell what phase the motor is by just looking at it or do you need to know what year it was made?

 

Are you refering to upgrade stages I.E. catback stage 1 up pipe down pipe catback and intake stage 2, turbo and injectors fuel pump stage three? That is not how its rated but thats what I understood your question to be. for example. I have up pipe down pipe cat back and intake and run a stage 2 map from cobb.

 

Every shop offers packages; each coming with different parts. From Power, Drivetrain, and Suspension packages. But in general speaking, and differs through different shops. . . IMO power stages are

Stage 1: Catback, Intake
Stage 2: Turbo-back, Intake, w/ or without tune
Stage 3: Turbo-back, Intake, FMIC/TMIC Upgrade, Turbo Upgrade, Injector Upgrade, Fuel Pump Upgrade
Stage 4: Stage 3 with Engine Internal Work. . .

 

phase 1 refers to the 2.5l engine 4 cam engine in 96-99 outback, 98 forester and 2.5 rs. phase 2 is sohc 2.5l engine 2000 OB - later , 99 forester ,2.5rs - later

 

so if i understand correctly a phase 1 motor is essentially the dohc in the older cars, and the phase 2 is a sohc in the newer cars. but where would and STIs be? a phase 1 because they are dohc? and would my 2006 2.5i be a phase 2? also are there any phases with the WRX 2.0l?

 

and no im not talking anything aftermarket

 

great jobs guys

 

It's a different bearing configuration on the Phase 1. Phase 1 thrust bearing in the middle. Phase 2 on the end. The thrust bearing placement on the phase 2 is considered to be superior. Not that phase 1 bad, just not as reliable long term. But my phase one engine went 246k miles so I leave that up to you.

cheers

poorman

 

is there any exterior identification? or is the only way to tell is to tear the motor down?

 

thats a challenge!!!!

i am on 160k on my stock motor