7A-FE Compression Ratio, Looking at changing the CR of my 7afe when I rebuild. Options

[PaukST]

Hey all, I'm trying to decide what to do with my 7AFE (have to take it apart due to a rod knock anyway). I've kicked around a few ideas (or maybe a lot ), and I'm currently researching what an increase in compression ratio might do. Does anyone have any info on this? I'm unsure of the potential difference in performance, and I can't seem to find any hard data on what pistons (4age, smallport 4age, 4agze) result in what CR. I've been trying to make sense of these tools and formulas - http://www.csgnetwork.com/compcalc.html http://s-86.com/s-cr.html and http://s-86.com/s-cr-chart.html - but I'm having a hard time digging out the relevant numbers. Doing the math myself or using the calculator I come up with significantly different numbers than their little handy chart, so I don't know what to think. Is this a futile exercise? Will I even be able to notice a performance difference over the stock 9.5:1 without having to use higher octane?

[Special_Edy]

My local import machine shop charges $35 to deck a 4cylinder head and $45 to deck a 4 cylinder block. A chemical dip is included in the price for the heads, Im not sure about the block.
This would be the route I would go, you can also get a thinner head gasket for some extra $s. Im not sure how many thousandths of an inch you can remove but with an inline 4 the only major issues you have to worry about are the valves and sparkplug hitting the piston and taking to much material off where the waterjackets are located.
Do some research and find out how many CCs to remove from the combution chamber. I think you could run 10 to 1 CR without needing high octane(unless you try to advance it) and once you get to 11 to 1 CR you will most likely need to go 93 octane. I think 13 to 1 and up requires racing fuel and that gets real expensive.

[mandrek]

My local import machine shop charges $35 to deck a 4cylinder head and $45 to deck a 4 cylinder block. A chemical dip is included in the price for the heads, Im not sure about the block.
This would be the route I would go, you can also get a thinner head gasket for some extra $s. Im not sure how many thousandths of an inch you can remove but with an inline 4 the only major issues you have to worry about are the valves and sparkplug hitting the piston and taking to much material off where the waterjackets are located.
Do some research and find out how many CCs to remove from the combution chamber. I think you could run 10 to 1 CR without needing high octane(unless you try to advance it) and once you get to 11 to 1 CR you will most likely need to go 93 octane. I think 13 to 1 and up requires racing fuel and that gets real expensive.

WOW!!! $45 to deck the block!!! awesome.. my shop here charged $135 to deck the block.. but he also told me that it was because the block is cast iron.. and not aluminum.. is that $45 for iron block aswell?

and to the OP... IMO do a clean rebuild, and then go turbo.. thats what im doing.. and all of my research shows it the best option, if not doing a swap.

[Special_Edy]

My local import machine shop charges $35 to deck a 4cylinder head and $45 to deck a 4 cylinder block. A chemical dip is included in the price for the heads, Im not sure about the block.
This would be the route I would go, you can also get a thinner head gasket for some extra $s. Im not sure how many thousandths of an inch you can remove but with an inline 4 the only major issues you have to worry about are the valves and sparkplug hitting the piston and taking to much material off where the waterjackets are located.
Do some research and find out how many CCs to remove from the combution chamber. I think you could run 10 to 1 CR without needing high octane(unless you try to advance it) and once you get to 11 to 1 CR you will most likely need to go 93 octane. I think 13 to 1 and up requires racing fuel and that gets real expensive.

WOW!!! $45 to deck the block!!! awesome.. my shop here charged $135 to deck the block.. but he also told me that it was because the block is cast iron.. and not aluminum.. is that $45 for iron block aswell?

and to the OP... IMO do a clean rebuild, and then go turbo.. thats what im doing.. and all of my research shows it the best option, if not doing a swap.

Yeah the fine print is *prices may vary
the head was definately a good deal.

I would say that for performance mods to your engine, increasing the Compression Ratio is one of those things that doesnt increase your fuel consumption, it just helps you extract more energy from the fuel you are already burning. Increased efficiency plus increased power is a win-win