breadstick Posted May 8, 2013 Share Posted May 8, 2013 I've been searching for a while, but I can't seem to find an answer. What, if any, differences are there between Legacy engines (2007 GT specifically) and STI engines? Are they the same short blocks with different throttle bodies, turbos, and intercoolers? Link to comment Share on other sites More sharing options...
Max Capacity Posted May 8, 2013 Share Posted May 8, 2013 There's a lot of discussion about this. The external piece's seem to be the main difference. Last year I put a ej257 short block in my wagon using the gasket kit for my 05 ej255. Some have talked about the pistons being different. Really its not a big deal. Here's my ej257 http://i185.photobucket.com/albums/x40/92Si/DSCN4652.jpg here's the ej255 http://i185.photobucket.com/albums/x40/92Si/DSCN4754.jpg 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
TheBlackPearl Posted May 9, 2013 Share Posted May 9, 2013 Intake manifolds are obviously different, and dual ACVS heads vs single AVCS heads are another that I know of. I thought something else in the heads were differnt too, maybe retainers? Somebody will inow for sure, but IIRC, it seemed like the heads and intake manifolds were the big difference. Self proclaimed PNW Craiglist find of the day Champion, April 2014. Link to comment Share on other sites More sharing options...
Zero1 Posted May 9, 2013 Share Posted May 9, 2013 Cams are completely different, single AVCS on the EJ255 vs. dual AVCS on the EJ257, forged internals on the EJ257, IM, injectors, turbo, TMIC, EJ257 is a semi-open deck block where the EJ255 is an open-deck block, the list goes on lol. The short blocks are swappable though Link to comment Share on other sites More sharing options...
stuck686 Posted May 9, 2013 Share Posted May 9, 2013 forged internals on the EJ257 are u sure?? Link to comment Share on other sites More sharing options...
bigjweb Posted May 9, 2013 Share Posted May 9, 2013 Short blocks are exactly the same and share the same parts numbers for early 4th gen models Link to comment Share on other sites More sharing options...
bigjweb Posted May 9, 2013 Share Posted May 9, 2013 are u sure?? 257 has the same cast pistons as the 255 Link to comment Share on other sites More sharing options...
sbw Posted May 9, 2013 Share Posted May 9, 2013 Lots of misinfo in here. Both shortblocks are the same. Not all 257s had variable timing on the exhaust cams all years. They both have forged rods, and cast pistons. Link to comment Share on other sites More sharing options...
sbw Posted May 9, 2013 Share Posted May 9, 2013 Oh the dishes are different on the pistons. There have been some minor changes to both blocks over the years so that needs to be considered too. Link to comment Share on other sites More sharing options...
bigjweb Posted May 9, 2013 Share Posted May 9, 2013 Oh the dishes are different on the pistons. There have been some minor changes to both blocks over the years so that needs to be considered too. Over the years there are some differences. But for 05 they are the same. Pistons included Link to comment Share on other sites More sharing options...
Zero1 Posted May 9, 2013 Share Posted May 9, 2013 EJ257's have forged cranks EJ255's don't... 2005 is the only exception for the bottom end being the same. Don't know how that makes them the same??? Link to comment Share on other sites More sharing options...
Max Capacity Posted May 9, 2013 Share Posted May 9, 2013 breadstick, why do you want to know ? That's the question I didn't ask sooner. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
BAC5.2 Posted May 9, 2013 Share Posted May 9, 2013 Cams are completely different, single AVCS on the EJ255 vs. dual AVCS on the EJ257, forged internals on the EJ257, IM, injectors, turbo, TMIC, EJ257 is a semi-open deck block where the EJ255 is an open-deck block, the list goes on lol. The short blocks are swappable though EJ257's have forged cranks EJ255's don't... 2005 is the only exception for the bottom end being the same. Don't know how that makes them the same??? Just so no one gets confused, I highlighted the wrong stuff in Red. [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
bigjweb Posted May 9, 2013 Share Posted May 9, 2013 Breadstick - go over here and look around: http://opposedforces.com/parts/info/10103AB440/ You can see what parts interchange and what parts do not Link to comment Share on other sites More sharing options...
breadstick Posted May 9, 2013 Author Share Posted May 9, 2013 Thanks for all the information. I'm looking to replace my engine with a short block from a local builder (vigilant motorsports) and he uses a new STI short block. I just wanted to be sure they will mate up. Its not something I'll do soon, but I'm info gathering right now. Link to comment Share on other sites More sharing options...
Max Capacity Posted May 9, 2013 Share Posted May 9, 2013 My 05 wagon has a STI ej257 short block, it's what most of us do. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Strizzy Posted May 10, 2013 Share Posted May 10, 2013 No body mentioned that 07+ Legacy switched to D25 heads, which bumps up the compression ratio. If you are shopping for pistons, they are usually rated with the B25 heads. So if you see a stock replacement STI piston rated at 8.2:1, your CR will end up around 8.5:1. IIRC, all EJ257 long blocks come with B25 heads. My bad luck build Link to comment Share on other sites More sharing options...
Zero1 Posted May 10, 2013 Share Posted May 10, 2013 Well thank you for the correction BAC. Perhaps you can help me understand why it would be better to have a 257 bottom end than a 255 bottom end? I've always been under the impression that the 255 was not as strong and could not hold the same power/boost as the 257, leaving the heads aside. Link to comment Share on other sites More sharing options...
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