GS/8g/Hyundai 4g64 piston comparison
Well now I have a spare 4g64 block lying around and began considering my options, a rebuild is in the works. However, I've been noticing more chatter on the 3G/8g boards for the past few years about the Hyundai version of the 4g64 (g4cs) and there seems to be a bit of grey area when it comes to compression ratio. I have a few questions...
1. What is the actual compression ratio of the 89-91(six-bolt, dohc/8V-sohc) and the 00-01(seven-bolt, dohc) Hyundai Sonata 4g64/g4cs pistons when paired with a Mitsubishi head?
2. How do they compare to the standard GS/8g pistons?
*I've found conflicting numbers ranging from 10:1 to 12.5:1 when mated to the Mitsubishi heads. Both the 1g/2g and 3g/Evo 8+ guys are saying that the Hyundai heads have a larger or higher capacity 'valve-cup'(not sure what to call it) in the combustion chamber. Which would compensate for the Hyundai high compression piston, but when the hyundai pistons are paired with a Mitsubishi designed head it would cause a much higher compression.
I'm trying to find what combination would be the most suitable for a decent higher compression n/a setup. I'm aware that the *discontinued* GS pistons have a 10:1 ratio while the sohc Mitsubishi version can go from 9:1-9.5:1. I'm just wondering how the Hyundai pistons would compare to the GS pistons in actual compression ratio, seeing that most of the sources I've found are conflicting.
If anyone has experience with the Hyundai pistons and possibly pictures of the piston shape so that we could compare it to other options, it would be very helpful and appreciated!