So I am in the middle of my mild build research and I'm looking for some pistons at this time. Figure stick with OEM and make my life a little easier and keep the somewhat factory reliability. Based on my build, I need some compression (Spec B's, itbs, headwork, etc..) so I was looking at the JDM ITR pistons. Based on the compression calculators I see online (http://www.zealautowerks.com/bseries.html), the P73-00 pistons will yield 11.32:1 compression. Figure I need to deck the block and head a little to ensure flatness, this should get me close to my 11.5:1 target with plenty of clearance (v2p).

However, I seem to find contradicting information when it comes to the actual comp ratio. Some sites say the P73-00 only yields 11:1 compression.

Am I missing something?

Craig - Who is leaning more and more to CR pistons

 

The Jdm b18cr pistons will get you around 11.1:1 oem but will obviously increase a bit by resurfacing the head and block. Only way to know for sure is to measure. If I were you I wouldn't get too caught up on a few tenths here or there on compression. Bottom line is that it's a good reliable number for pump gas. Nailing the engine assembly, bolt ons and tune will be much more rewarding for your efforts.

 

The 11.1:1 is with b16 head should net around 11.4:1 if you used a gsr head, but other factors come into play, bore size, how much block been decked or head milled, head gasket thickness , dished or flat face valves, etc. as mentioned above anywhere around that comp. of 11.1:1, a good assembly and parts that work good together and a tune on pump gas , you will have a fun, reliable motor.