Frugal and Fast?
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From: Anytown, USA
Car Info: '00 RS, Subrosa Letum
Frugal and Fast?
I-Speed has just anounced a 2.5 STI block w/ custom pistons(if they were mass quantity the wouldn't be custom) for about $3000.
Since the bore on 2.5s is about four inches, some aftermarket Chevy pistons should be able to work(given the right specs) for a whole lot less money. My 440 had a 4.35 inch bore and eight pistons only cost me about $800. Being as that this is much more high tech than some Mopar engine, are there any important things to worry about when it comes to Subaru pistons like can I use a flat topped piston? I also had a pretty important question for I-Speed but maybe someone else can help.
Will phaseII 2.5 heads fit the STI block(w/ or w/out new pistons)?
Any insight is would be much appreciated.
Since the bore on 2.5s is about four inches, some aftermarket Chevy pistons should be able to work(given the right specs) for a whole lot less money. My 440 had a 4.35 inch bore and eight pistons only cost me about $800. Being as that this is much more high tech than some Mopar engine, are there any important things to worry about when it comes to Subaru pistons like can I use a flat topped piston? I also had a pretty important question for I-Speed but maybe someone else can help.
Will phaseII 2.5 heads fit the STI block(w/ or w/out new pistons)?
Any insight is would be much appreciated.
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From: Reno, NV
Car Info: 1993/2000/2001 GF4 mostly red
It's mostly a matter of the distance between the center of the wrist pin on the piston to the various points on the face of it. If that length is the same, then sure, other brand pistons would work. Since the forgies used in the i-speed motors are usually flat with a small 'dish' in the center, I imagine they will be appropriate, CR and all, for turbocharging. Using phase II pistons would cheat you out of having forged pistons, as well as keeping the compression ratio high, which causes quite a weak point in your engine. 4.35" is quite a leap from 3.92" though. I'm thinking you woud need a different engine to swap pistons with.
Last edited by Kevin M; Aug 20, 2003 at 09:56 PM.
Thread Starter
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From: Anytown, USA
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I think you have missed my point. I was merely comparing prices between eight large pistons and four small pistons. My other point was that it should be possible to put sohc 2.5 heads on the STI block, would I need new pistons then? $3000 for a short block is a bit pricey, especially when the factory STI block is only $1200(I've heard). Since the bore is ABOUT four inches, I am pretty sure there are other companies out there that can make pistons for less $.
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You might be able to find your own forged pistons for less, possibly. I would still not recommend using stock phase II pistons though. You will need the forgies to make power safely.
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JohnQGearhead - PhaseII 2.5 heads will work with the 2.5 STi block (stock or with aftermarket pistons). You just need to be sure that your CR are within spec. That's of course you are looking for something that is reliable and won't detonate like crazy.
As for the STi block price: People have commented that they know what it costs and where they can get it from. It is always specualtion until someone, other than ourselves, actually purchases the item in question.
If you choose to get the block from someone/somewhere else and then use our pistons, then that's ok.
Chris
I-Speed USA
cescamilla@i-speedusa.com
As for the STi block price: People have commented that they know what it costs and where they can get it from. It is always specualtion until someone, other than ourselves, actually purchases the item in question.
If you choose to get the block from someone/somewhere else and then use our pistons, then that's ok.
Chris
I-Speed USA
cescamilla@i-speedusa.com
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We are trying to get multiple blocks which would hopefully drive down the cost.
Right now, according to a Subaru Rep, 70% of the STi 2.5 blocks are slotted for dealers and the remaining 30% will be for anyone else. The price will vary depending on which dealer/who you get the blocks from.
All this being said, we cannot confirm a price until we sort out a these plus a few more details.
Chris
I-Speed USA
cescamilla@i-speedusa.com
Right now, according to a Subaru Rep, 70% of the STi 2.5 blocks are slotted for dealers and the remaining 30% will be for anyone else. The price will vary depending on which dealer/who you get the blocks from.
All this being said, we cannot confirm a price until we sort out a these plus a few more details.
Chris
I-Speed USA
cescamilla@i-speedusa.com
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