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2.5L Crank Specs-Searched

Posted: Fri Apr 10, 2009 3:50 am
by subytech
Ok I'm thinking of a stroker build in the distant future but I have a choice right now between 2 cranks. First choice is out of a 98 Legacy GT 2.5L DOHC, second choice is out of a 2.57L 07 STi, now before jumping to the immediate conclusion that "STi" means better, are there any differences between the cranks, dimensionally or otherwise. I know the Leg GT crank will work, my roommate has one in the stroked 2.2 sitting in the engine bay of his 92 wagon in the garage, but is the STi one dimensionally the same? I've looked all over the net and can't find anything. I'd measure the cranks but I'm still waiting for the STi block to be released, as it were, by Subaru to my dealership and I can't touch it until then.

Posted: Fri Apr 10, 2009 4:45 am
by PhyrraM
The Legacy crank is a phase 1 crank. The thrust bearing is on the #3 main journal. The rod bearings are 48mm in diameter.

The STI crank is a phase 2. The thrust bearing is on the #5 main journal. The rod bearings are 52mm diameter.

Your EJ22T case needs a phase 1 (#3 thrust) crankshaft, unless your willing to have the block machined for the #5 thrust.

48mm forged rods are harder to come by, but Outfront motorsports usually stocks them.

Search Nasioc, rs25.com, and here for "ej22t stroker" or "2.35 stroker" and you will get about a weeks worth of reading. It's been done many times, but the current fad is to just use a STI shortblock.