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Discussion Starter · #1 ·
I was think of rebuilding my motor and was wondering if i boar it out what piston will fit and how far i can boar. Also what is stock compression ratio id like to go higher than stock because i use premium gas anyway. Anyone know of cost for JUST boaring (i can get a honer and put pistons in myself)
 

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if your willing to throw out that much money and are that skilled whynot just throw a turbo on? it would be eaisier, probably cheaper and maybe more hp, plus you wont crack your block under load
 

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Figure the price of boring as the same price of a rebuild.

IME/O, by just boring out the block you'll gain low end HP (but sacrifice high end HP) and shorten the power band (peak would be moved to around 4000-4500 RPM).

But if you did it right, you'd gain more torque. IIRC, the bore on the 2.5L is 3.310in, IMO I wouldn't push it past 3.5in (if the block could even take that, I doubt it could w/o sleeves). This would add about 18 ci to you engine also.

If you've got the money to do it and the money to replace the engine, and are willing to take the risk, then go for it. Get a copy of Dyno2000 and mess around w/ it.

Just my $0.02
 

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Increasing bore/stroke ratio always helps top end. The only question is if the rod big end can deal with the extra weight of the piston at 6500 rpm. Assuming you don't used forged pistons...and that valve area is large enough to support the higher airflow...
 

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slartibartfast said:
Increasing bore/stroke ratio always helps top end. The only question is if the rod big end can deal with the extra weight of the piston at 6500 rpm. Assuming you don't used forged pistons...and that valve area is large enough to support the higher airflow...
i had my 2.7 rebuilt, bored 0.030 over, with forged pistons, and the heads ported and polished. never dynoed it, but damn did it go.... sorry i dont have any specs, i had someone do the work for me.
 

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Discussion Starter · #6 ·
cigarettcancerman said:
if your willing to throw out that much money and are that skilled whynot just throw a turbo on? it would be eaisier, probably cheaper and maybe more hp, plus you wont crack your block under load
you obvisously have never dealt with a turbo

first ill start with the cost to have someone do it would be thousands and Maintinence is crazy

Or the skill to make a turbo set up i dont have but i have rebuilt motors before

And IF i were to go to turbo Id have to put lower compression pistons in ANYWAY

Also the stress a bigger piston put on a motor is NOTHING compared to a turbo

a turbo costs more requires more maintence and puts the motor under more stress and i dont have the metal working skills to make a turbo setup

SO its safe for me to say YOU are WRONG!
 

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Discussion Starter · #7 ·
AndaHeart said:
i had my 2.7 rebuilt, bored 0.030 over, with forged pistons, and the heads ported and polished. never dynoed it, but damn did it go.... sorry i dont have any specs, i had someone do the work for me.
What pistons and head gaskets did you use and model #s please?

and

Does anyone know of stock size piston with higher compression ratios?
p and a?

or can answer my origanal question
 

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Well, here are the stock specs for the engine (via Autozone):
2.5L
Bore x Stroke : 3.31in x 2.95in
Compression : 9.0:1

2.7L
Bore x Stroke : 3.43in x 2.95in
Compression : 9.0:1

First question, How far can I bore? To find this out you need to find out the sidewall width.

Second question, What's the cost of just boring? Go ask your local mechanic, the price differs from area to area. IIRC, where I live that JUST the boring will cost me $250 (or it may have been $350). That doesn't include ripping the engine out or anything else.
 

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There are variances in every make and model of mass produced engine blocks. The safest thing to do is bring the block you are going to use to a quality machine shop and have it sonic checked. They can determine the thickness of the existing cylinder walls which will tell you how far you can safely overbore it.

In regards to what pistons to use, I have heard (but never confirmed) that H22A pistons are a direct swap. Personally, I would order custom made pistons. I perfer Wiseco, but most folks in the Honda crowd seem to favor JE. Any piston manufacturer can custom build pistons. They should run you about $150 each, give or take.

reeeky2001, did you get that from autozone's website? I am curious to see the specs for G2 3.0's and 3.2's.
 
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