Bore of STi Cylinders - Subaru WRX Forum
 
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post #1 of 11 Old 10-13-2006, 11:24 AM Thread Starter
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Bore of STi Cylinders

I am going to go with forged internals as well as the GT35R turbo in my 04 STi. I am not planning on boring out my cylinders at all. Does any one know what the bore and cubic inches of the stock STi cylinders are? Thanks

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post #2 of 11 Old 10-13-2006, 11:37 AM
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If you're swapping internals, it's a good idea to do at least a .030 over bore to remove any surface imprefections and ensure the rings seat well.

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post #3 of 11 Old 10-13-2006, 11:45 AM Thread Starter
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yea i was worried about that. how much does a shop charge to bore out your cylinders. Do you know what the final bore would be? I'm just trying to price things out and i need to figure out how big my pistons need to be. Thanks

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post #4 of 11 Old 10-13-2006, 02:56 PM
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You'll have to find an engine builder or machine shop and price them out. If you're gonna do this you should be prepared to spend some money. You can do it on the cheap side, just throw some forged con-rods and pistons in and call it a day, or... You can bore the cylinders, knife-edge the crank, and have the whole thing balanced and blueprinted. More money, but at the very least you'll know the thing was done right and have an idea of what it can take.

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post #5 of 11 Old 10-13-2006, 06:25 PM Thread Starter
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o believe me I am doing this right, over the winter I am planning on doing extesive mods after i get the engine build done. As far as the engine goes though, I am going with cobbs rods and pistons, new main bearings, and rod bearings. I first need to find a reputable shop around here to do this. Does anyone know of any shops in minnesota or not too far from it that could handle this job?

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post #6 of 11 Old 10-13-2006, 07:16 PM
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Quote:
Originally Posted by rex-ya
If you're swapping internals, it's a good idea to do at least a .030 over bore to remove any surface imprefections and ensure the rings seat well.


Very big +1...I only did a .02..but you should bore it a bit

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post #7 of 11 Old 10-13-2006, 08:44 PM
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Keep us updated. I'd like to know for when I get to that point. I want a GT35R kit so bad....I think I have a kidney I don't need.....

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post #8 of 11 Old 10-14-2006, 12:12 AM Thread Starter
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yea i will definatly keep you guys posted. I gotta get all the funds together first. This is going to be an all winter project so i can have it ready for the track next summer. Thanks for the input.

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post #9 of 11 Old 10-14-2006, 12:15 AM Thread Starter
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Just out of curiosity, how hard is it to rebalance the crank? I am going to be running the stock crank.

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post #10 of 11 Old 10-14-2006, 12:19 AM Thread Starter
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Also, I am going to be running a considerable amount of boost, and am expecting 500+hp after the UTEC with a tune. I have a feeling that if i miss a shift with 500 hp, my stock tranny might shred like tissue paper. I'm not a bad driver, but accidents can happen/ I have heard of people cryo treating their trannys. Would this be a good investment?

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post #11 of 11 Old 10-21-2006, 11:11 AM
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definitely. Cryo-treating adds anywhere between 30 and 70% to durability a wear rating. (depending on the original condition) while you're at it, you could do the block, internals, the turbo itself. It's worth it if you have the spare cash.

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