Moderators BarManBean Posted July 18, 2013 Moderators Share Posted July 18, 2013 Can someone give me a run down of which engine heads will work for an LGT? My understanding is that an EJ255 / EJ257 shortblock is pretty much the same, but the heads are different across model years. I also thought that the 257 was basically the replacement for the 255 but I'm finding that's not the case since it appears that an '04 forester started with a 257...color me confused. If anyone can point me to a primer for what matches up to what, that would be great. At this point I'm not even sure exactly what to search for. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Rester5350 Posted July 18, 2013 Share Posted July 18, 2013 From what little I understand right now, it depends on the AVCs ( dohc, sohc) and the ecu. Hope that helps. Link to comment Share on other sites More sharing options...
Rester5350 Posted July 18, 2013 Share Posted July 18, 2013 This has been one of my study guides. http://forums.nasioc.com/forums/showthread.php?t=1431376 Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 so SOHC, DOHC, and DOHC with dual AVCS? "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
frank_ster Posted July 18, 2013 Share Posted July 18, 2013 sohc, dohc ,dohc intake avcs, dohc dual avcs. if you put heads with out avcs on at least the intake a lgt you will have ecm issues since the cam position sensor and notches are different. Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 It looks like D25 heads are what you find on LGTs...need to do some more reading. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Gex Posted July 18, 2013 Share Posted July 18, 2013 D25, B25, and V25 should all work. Good thread about flow between the three. http://forums.nasioc.com/forums/showthread.php?t=2034555 Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 D25, B25, and V25 should all work Do you know what motors these are normally found on? "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Gex Posted July 18, 2013 Share Posted July 18, 2013 D25 EJ255 B25 04-06 STI V25 07 STI In 08 they went dual AVCS as far as I know. Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 Are 08+ wrx's dual AVCS or just the sti's. And thanks for the info, BTW! "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Gex Posted July 18, 2013 Share Posted July 18, 2013 98.5% sure 08-10 WRX's are single AVCS. Also if you get heads off a 06+wrx or 07 STI you will need the air pump block off plate. http://www.wrxtuners.com/forums/f103/avcs-faq-28052/ Another good read Link to comment Share on other sites More sharing options...
Nrw Posted July 18, 2013 Share Posted July 18, 2013 Are 08+ wrx's dual AVCS or just the sti's. And thanks for the info, BTW! Just the 08+ STI's are dual AVCS (well and the 5th gen LGT) 05-06 LGT's have the same B25 heads as the single AVCS STI. D25 came on the 07-09 LGT, and 2.5l WRX's IIRC. Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 Thanks Neil. But just to confirm the B25 and D25 heads are swappable, right? I'm guessing you would need a pump block off plate as well if putting D25 heads into an 05/06, but if just building the longblock they would just slap on there fine... "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
jgross2020 Posted July 18, 2013 Share Posted July 18, 2013 I bought a set of reman heads a couple of weeks ago. B25 was the casting number on the ones I took off and on the reman heads. But the reman heads had an extra hole for a cam sensor next to cam gear itself on the right side head. (Left side exactly the same as old head) I had to buy a dummy sensor to plug in hole so i wouldn't have an oil leak. But I am not having any problems with them. Link to comment Share on other sites More sharing options...
Nrw Posted July 18, 2013 Share Posted July 18, 2013 Thanks Neil. But just to confirm the B25 and D25 heads are swappable, right? I'm guessing you would need a pump block off plate as well if putting D25 heads into an 05/06, but if just building the longblock they would just slap on there fine... IIRC the combustion chamber is smaller on the D25 head. I may be wrong on that one though. Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 so....slightly higher overall compression? that makes sense in my head, but as mentioned I'm only just starting to dive in here so that may have no basis whatsoever More or less I just want to be able to build a stock-ish block with forged pistons... "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Nrw Posted July 18, 2013 Share Posted July 18, 2013 This thread might be of some help http://forums.nasioc.com/forums/showthread.php?t=1856856 Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 Pretty neat: http://forums.nasioc.com/forums/showthread.php?t=1856856 "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Nrw Posted July 18, 2013 Share Posted July 18, 2013 tree'd ya Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 Haha, we just posted the same damn thread. I'm reading through part of it now but most of it is way over my head. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
I Donated thefultonhow Posted July 18, 2013 I Donated Share Posted July 18, 2013 Just the 08+ STI's are dual AVCS (well and the 5th gen LGT) 05-06 LGT's have the same B25 heads as the single AVCS STI. D25 came on the 07-09 LGT, and 2.5l WRX's IIRC. Correct, AFAIK. IIRC the combustion chamber is smaller on the D25 head. I may be wrong on that one though. Also correct, AFAIK. I had D25s in my 05 due to the longblock swap after I spun a bearing, and Mike (m sprank) said I had to be careful about which forged pistons I got. IIRC, I bought Wisecos, and he gave me an upgrade to CPs because they "work better" with D25 heads. Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted July 18, 2013 Author Moderators Share Posted July 18, 2013 I was leaning towards CP prisons anyway so that's fine. Seems that there is some speculation that the d25 heads may flow a bit better too... "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
yardie Posted July 18, 2013 Share Posted July 18, 2013 Also correct, AFAIK. I had D25s in my 05 due to the longblock swap after I spun a bearing, and Mike (m sprank) said I had to be careful about which forged pistons I got. IIRC, I bought Wisecos, and he gave me an upgrade to CPs because they "work better" with D25 heads. I have a similar experience as you in that i had to swap in the b25 with a new EJ257 short block in my '08 and I was curious if you noticed any difference between the two heads d25 @ 8.4:1 having a tad more compression than the b25 @ 8.2:1. Also were there any key areas needed to be fine tuned like maybe timing and avcs? Link to comment Share on other sites More sharing options...
I Donated thefultonhow Posted July 18, 2013 I Donated Share Posted July 18, 2013 I have a similar experience as you in that i had to swap in the b25 with a new EJ257 short block in my '08 and I was curious if you noticed any difference between the two heads d25 @ 8.4:1 having a tad more compression than the b25 @ 8.2:1. Also were there any key areas needed to be fine tuned like maybe timing and avcs? I went from Stage 1 to Stage 3 at roughly the same time I swapped in the engine from an 06 WRX, so it's hard to do an apples-to-apples comparison. Especially because I don't even own the car anymore... I think you are in a much better position to judge than I was/am. Link to comment Share on other sites More sharing options...
Xplosivo1 Posted July 18, 2013 Share Posted July 18, 2013 I was leaning towards CP prisons anyway so that's fine. Seems that there is some speculation that the d25 heads may flow a bit better too... This is correct, as long as you use stock compression ratio with each head (stock wrx with B25, stock LGT with D25) you won't run into problems. When you start getting away from stock piston CR though reliability and fueling options come into play. If your CR is too high pump gas will ruin the engine. Man where all you head gurus a month ago when I was trying to swap B25 and D25 heads? Link to comment Share on other sites More sharing options...
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