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Old 03-30-2006, 03:25 PM   #1
HamFist
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Default pop-up pistons...

Anybody make them for a 2.5? (12:1 compression or better?)
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Old 03-30-2006, 03:42 PM   #2
herewegoagain
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I think Paeco does. But their customer service sucks.
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Old 03-30-2006, 10:04 PM   #3
Crawford Performance
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We design custom pistons for any application

Quirt Crawford
www.crawfordperformance.com
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Old 03-30-2006, 11:07 PM   #4
HamFist
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No offense quirt, but I wanted to see if anything was available off the shelf. That piston does look nice. I give people the benefit of the doubt, and I don't want to trudge up any crap. But, how well do they fit? I avoided that whole thread except for a parody "for rent" post .
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Old 03-31-2006, 08:27 AM   #5
JonofScio
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yeah actually, my first mention was going to be crawford, but he already whored out this thread with his huge, and sexy picture of a piston already. hey, if I could get that picture on a huge poster, I'd put it in my room. Think that would make my fiance jealous?

TWE also makes high CR pistons. look for them at rallitek. 11.2, I think they had 12:1. But you're looking at more than CP (crawford performance) sell his pistons at. He sells his sets for a little under $600, but I don't know if he would make you up a nice new 12:1 piston set made for the EJ25 head at that price.

I'll see if I can find any other manuf. that make high CR pistons... one sec...

whoa damn. rallitek sure changed their page. no more high CR pistons it seems... maybe they still carry them. I couldn't find (google) JE or Wiseco high CR pistons.

TWE DOES have 12.5:1 (made for DOHC head chamber) EJ25 pistons, and the other piston sets are at $700+. so who KNOWS how much they cost. But I'm sure they are pretty nice. *cough* crawford. *cough*
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Old 03-31-2006, 10:26 AM   #6
Crawford Performance
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Quote:
Originally Posted by HamFist
No offense quirt, but I wanted to see if anything was available off the shelf. That piston does look nice. I give people the benefit of the doubt, and I don't want to trudge up any crap. But, how well do they fit? I avoided that whole thread except for a parody "for rent" post .
No offense taken HamFist

An off the shelf piston at 12:1+ compression might be hard to come by, but the internet is a great tool... I do not understand your question about "how well do they fit", could you please explain?

Quirt
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Old 03-31-2006, 01:55 PM   #7
TypeC
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Quote:
Originally Posted by Crawford Performance
I do not understand your question about "how well do they fit", could you please explain?

Quirt
+1. Quirt will send you pistons to spec and you size (hone/bore) your bores to fit.
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Old 03-31-2006, 03:21 PM   #8
ImprezaRSX
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Go to TWE. They have high compression pistons that due to their "high quench" design can run lower octanes than other piston designs.
Basically what that means is you can run more timing than other piston manufactures and get more torque with slightly leaner AFRs.

They did afterall make a 300HP N/A subaru 2.5L.
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Old 03-31-2006, 03:24 PM   #9
banzai
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It's not a good idea to bore/hone off what someone tells you. wait until you have the pistons in hand so the shop can match them to the individual cylinders.
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Old 03-31-2006, 03:51 PM   #10
TypeC
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Quote:
Originally Posted by banzai
It's not a good idea to bore/hone off what someone tells you. wait until you have the pistons in hand so the shop can match them to the individual cylinders.
That's what I was saying. Order 99.5 or 100mm pistons, and give the machine shop the pistons and block.
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Old 03-31-2006, 03:53 PM   #11
banzai
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Quote:
Originally Posted by TypeC
That's what I was saying. Order 99.5 or 100mm pistons, and give the machine shop the pistons and block.
apologies, i misunderstood.
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Old 03-31-2006, 04:07 PM   #12
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Quirt, I was curious about the clearances for your pistons. I didn't want the piston/bore clearances to be too loose. I'm looking at taking my factory n/a 2.5L and just honing the cylinders. The block has 58k miles on it. Upgrade to Crower or Eagle rods and clevite bearings and reuse my stock crankshaft. The overall bore/stroke dimensions would stay the same for my engine. TWE would have a slight bit of bias for me because they would very likely fit their own camshaft specs, too. I don't want valve/piston contact. Redline will be a conservative 7k and I plan on using alcohol.

What's just as appealing is reusing stock pistons with better rods and new bearings and staying at 10:1 compression. Wait for my blower kit to be done and just run 5psi with E85, cams, and a retune. I should have enough there to make well in excess of 300hp.
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Old 03-31-2006, 06:33 PM   #13
ImprezaRSX
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you'd be better off upgrading to the twe pistons anyway. Even if you use the same compression ratio you will get more power from the setup. You could go down to 9:1 and bump the supercharger up to 10psi easy with lots of room for more.

I'd just pay the extra 200 bucks to get the cylinders bored to 100mm and fitted custom to your pistons. It's the only way to ensure your clearances are correct. If you try to slap in 99.5mm pistons, no matter who they are from, your chances are low that you'll be noise free.
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Old 03-31-2006, 11:50 PM   #14
TypeC
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Quote:
Originally Posted by ImprezaRSX
I'd just pay the extra 200 bucks to get the cylinders bored to 100mm and fitted custom to your pistons. It's the only way to ensure your clearances are correct. If you try to slap in 99.5mm pistons, no matter who they are from, your chances are low that you'll be noise free.
I had my machine shop measure and hone my cylinders to fit 99.5mm pistons with .0026" PW clearance. The factory service limit is .002, so assuming the sleeves are straigh (Taper, round, etc) the normal bore should fit. But then again, this was on a 5K mile block.

But yeah, if they are custom pistons, you'll be SOL if they don't fit (no exchanging).
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Old 04-01-2006, 02:02 PM   #15
ImprezaRSX
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Quote:
Originally Posted by TypeC
I had my machine shop measure and hone my cylinders to fit 99.5mm pistons with .0026" PW clearance. The factory service limit is .002, so assuming the sleeves are straigh (Taper, round, etc) the normal bore should fit. But then again, this was on a 5K mile block.

But yeah, if they are custom pistons, you'll be SOL if they don't fit (no exchanging).
yeah, 5k and 58k are a bit different.
If you were able to achieve those tolerances on each piston that's awesome. Was your block an all A or all B block? all my blocks except one have been ABAB blocks. Did they do it by a data sheet or did they actually measure each piston?
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