WTF people.

CTR pistons in an otherwise stock b18c5 yield 12.4:1 and 12.8:1 compression. (81.25mm Oversived pistons)

Please don't talk about compression if you don't know. Most of the compression calculators do not take all necessary variables into consideration.

CTR Pistons = PCT.

quote from omniman -

stock type-r motor with ctr pistons
head Gasket 2.8cc big vol= 488.3cc
piston dome vol. 6.3cc small vol= 39.2cc stock type-r=12.45
camber vol. 44cc
deck height .25mm 1.3cc
cyl vol. 449.1cc

b16 pr3 pistons, b18c type-r pistons and b16b ctr pistons all have a different compression height. the pr3 pistons have the smallest and the ctr pistons have the biggest. with type-r in the middle