I'm trying to figure out this whole compression theory crap.... Simple favor to ask of you guys....... Please post your year, which intake manifold it came with, and if it's a USDM or JDM b20b...... LASTLY, if it has a 3 layer or 2 layer head gasket.... if you don't know how to tell, it's really easy, just look at the gap right here:


or here:


I'm trying to figure out what the standard is. Especially from you USDM B20b owners. Mine LOOKS like a 2 layer to me.... My friend tells me the standard should be a 3 layer.... so this is what I am checking now...... If the standard is a 3 layer, then perhaps, some JDM B20Bs do have 9.2 compression because of the thinner head gasket. All 96-98 B20bs prolly do have P3f (lower compression) pistons (versus the higher compression PHK pistons), but with a 2 layer gasket (if it's not the standard), it should yield a higher compression.....

So far from my research on a bunch of boards, the going theory is.......

96-98 JDM B20B = 8.8 Compression
97-98 USDM B20B = 8.8 Compression

99+ JDM B20B = 9.6 Compression
USDM B20Z = 9.6 Compression...

And if your still stuck in the past..... NO, not all JDM b20b's have 9.6 compression. That was alreayd been proven by many (pulling the head and looking at the pistons).