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Old 04-06-2011, 08:32 PM   #51
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cleaned,

46.6cc
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Old 04-06-2011, 08:42 PM   #52
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Wow, thanks for the quick response! I may have to use thicker than oem sti gaskets, the pics make it look like they shaved off more than they needed. May even need to cc both heads to check they are close. Man it sucks having only a couple of local machine shops, and they deal with 99% domestic. After dealing with them previously getting the heads and flywheel surfaced, I decided to take the 257 block to houston to find someone competent in subaru tech.
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Old 04-06-2011, 09:00 PM   #53
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what pistons are you going to run?
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Old 04-06-2011, 09:09 PM   #54
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Originally Posted by Maxwell Power View Post
what pistons are you going to run?
Trying to decide on:

JE 291060 8.5
CP SC7421 8.2
Wiseco K598M100 8.5

I'd like to have 8.2 CR ideally, also want offset wrist pin for quietest possible but surely normal will do

Last edited by 2slofouru; 04-07-2011 at 10:55 PM. Reason: changed je cr
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Old 04-07-2011, 01:14 AM   #55
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after reading all the thread, so if i own a 08STi with stock pistons, and change the pistons... the only piston that should keep the same CR is the wiseco?? both CP and JE will drop my power due lower CR???

curious....
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Old 04-07-2011, 07:48 AM   #56
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Originally Posted by xandi911 View Post
after reading all the thread, so if i own a 08STi with stock pistons, and change the pistons... the only piston that should keep the same CR is the wiseco?? both CP and JE will drop my power due lower CR???

curious....
They make pistons for normal compression ratio, I just listed those because I'm looking for a lower compression piston to make up for my smaller volume heads so I don't end up with a substantially higher than stock compression level.
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Old 04-07-2011, 10:15 AM   #57
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Originally Posted by 2slofouru

Trying to decide on:

JE 291060 8.2
CP SC7421 8.2
Wiseco K598M100 8.5

I'd like to have 8.2 CR ideally, also want offset wrist pin for quietest possible but surely normal will do
Je is 8.5
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Old 04-07-2011, 10:16 AM   #58
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Quote:
Originally Posted by xandi911
after reading all the thread, so if i own a 08STi with stock pistons, and change the pistons... the only piston that should keep the same CR is the wiseco?? both CP and JE will drop my power due lower CR???

curious....
Isn't the 08 sti 8.2
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Old 04-07-2011, 03:51 PM   #59
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Isn't the 08 sti 8.2
but JE and WISECO have pistons that keep my CR like STOCK?
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Old 04-07-2011, 03:59 PM   #60
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but JE and WISECO have pistons that keep my CR like STOCK?

nope

the dish on the JE piston is 16.5cc.
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Old 04-07-2011, 04:27 PM   #61
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didn't the 08+ sti have a sligthly shorter rod as well?
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Old 04-07-2011, 04:34 PM   #62
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not that I know of....

guess I should look into that.

Last edited by Maxwell Power; 04-07-2011 at 04:44 PM.
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Old 04-07-2011, 05:05 PM   #63
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the answer is no. Unless it's about 3 thou. I measured the compression height of the 08+piston and the 06STi piston. Both were the same within' 3 thou.
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Old 04-07-2011, 05:24 PM   #64
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yeah, it was the rod spec that changed. I think Juan Medina had shown it to me...He quoted Quirt, so it's only so reliable

Edit: found it
http://forums.nasioc.com/forums/show...8&postcount=20
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Old 04-07-2011, 07:03 PM   #65
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nope

the dish on the JE piston is 16.5cc.
and this means... my CF will increase OR DROP?
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Old 04-07-2011, 07:11 PM   #66
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Increase
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Old 04-07-2011, 08:02 PM   #67
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and this means... my CF will increase OR DROP?
Increase. Which isn't a bad thing.
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Old 04-07-2011, 11:00 PM   #68
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Je is 8.5
My bad, I was thinking that because that JE piston is designed for use with the 257 block and ej205/207 heads to maintain 8.5. Its possible I could end up with just a tad higher with the proper gaskets. I'll have to remember to try and call JE tomorrow. Reading their site (which doesn't list weight of the pistons) there are some interesting facts. They also mention offset wrist pins but don't state any of their subaru pistons are. If I could confirm the JE model I listed had offset pins that would push me to get them as long as the CR wasn't excessively high.
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Old 04-08-2011, 10:10 AM   #69
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JE has offset wrist pins...Nick, their import rep, is/was a subie guy.
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Old 04-08-2011, 11:57 AM   #70
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My bad, I was thinking that because that JE piston is designed for use with the 257 block and ej205/207 heads to maintain 8.5. Its possible I could end up with just a tad higher with the proper gaskets. I'll have to remember to try and call JE tomorrow. Reading their site (which doesn't list weight of the pistons) there are some interesting facts. They also mention offset wrist pins but don't state any of their subaru pistons are. If I could confirm the JE model I listed had offset pins that would push me to get them as long as the CR wasn't excessively high.

You're looking at a different piston. We are talking about pistons for the STi heads. JE offers a piston for the S20 heads. I don't recommend running it however due to the shrouding of the valves on the S20 head limiting power and creating hot spots. It's not the fault of the piston, it's the fault of going with a hybrid.
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Old 04-08-2011, 07:16 PM   #71
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You're looking at a different piston. We are talking about pistons for the STi heads. JE offers a piston for the S20 heads. I don't recommend running it however due to the shrouding of the valves on the S20 head limiting power and creating hot spots. It's not the fault of the piston, it's the fault of going with a hybrid.
Which piston are you referring to? I posted the piston JE offers that is designed for the 2.0 head and the 2.5 (sti) block. Aren't we talking about the same one? JE 291060 ? I thought Dave was running this model. Which part number are you referring to, Maxwell?
This type, 100mm with older style square countersunk top:
http://www.jepistons.com/Catalogs/Sp..._ej20head.aspx

Last edited by 2slofouru; 04-08-2011 at 07:33 PM.
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Old 04-14-2011, 07:27 AM   #72
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Ok, good info!

Still a bit confused, I have a blown 05 LegGT which exept for the block saying it's a EJ255 in reality it's a EJ257.

My heads were scored with the cams so which heads should I go with? Was thinking on going with new aftermsrket pistons (bored to 100mm) and 257 heads. Cam profiles the same between the two?
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Old 04-14-2011, 10:46 AM   #73
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the block halves themselves are the same. You had B25 heads which are the smaller ports. You can go to the newer heads with the exhaust air ports but simply block those off and you're good to go.

I've never cross references the PN's nor measured for the cams though. I'd suspect that they're the same knowing subaru but I could be wrong.
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Old 04-14-2011, 11:37 AM   #74
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EJ255 and EJ257 cams are identical.

If your 05 came with the B25 heads, they are the exact same head as an STi as well.
If your 05 came with the D25 heads, they are the same as an 06+WRX.
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Old 04-14-2011, 11:45 AM   #75
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^^^05 LGT heads were a split mid-model year?
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