In my research for my build I needed to calculate the c/r of a SR20VE with the N1 head so I could work out if the pistons would need machined to bring it down to a sensible level. Since it was a bloody nightmare trying to get all the data together I thought I'd fire up the info to save others the grief.But remember this data has come from the web & books, I havent verified it personally so dont take it as 100% accurate, more of a guide.

1.2mm SR20 head gasket volume = 6.965cc (0.425 cu inch)
Deck clearance volume(stock value) = 0.737cc (0.045 cu inch)
SR Deck Height = 211.3mm

SR16VE piston crown volume = 9.6cc (0.586 cu inch)
SR16VE N1 piston crown volume = 7.5cc (0.457 cu inch)
SR16VE piston crown volume = 9.6cc (0.586 cu inch)
SR20VE piston crown volume = -4.6cc (-0.281 cu inch)
SR20VE 20V piston crown volume = -2.4cc (-0.146 cu inch)

SR16/20VE (inc. 20V) combustion chamber volume = 41.8cc (2.55 cu inch)
SR16VE N1 combustion chamber volume = 37.4cc (2.28 cu inch)

SR16VE stroke length = 2.705" (68.7mm)
SR20 stroke length = 3.386" (86mm)

SR20/16 cylinder bores = 3.386" (86mm)

Comp Ratio=(Uncompressed Volume+Compressed Volume)/Compressed Volume or Comp Ratio = (Clearance Volume + Swept Volume)/Clearance Volume

Using this static compression ratio calculator:
http://www.race-cars.net/calculators/co ... lator.html

N1 head with the 2 litre crank, rods and N1 pistons works out about 14.5:1...... oh dear.
N1 head with the 2 litre crank, rods and SR16 pistons works out about 15.4:1...... oh shit.
N1 head with the 2 litre crank, rods and SR20VE pistons works out about 11.2:1...... not bad but still a bit low.
N1 head with the 2 litre crank, rods and SR20VE 20V pistons works out about 11.64:1...... not bad but still a bit low. Not even sure the 20V's can be used.
N1 head with the 2 litre crank, rods and SR20DE flat top pistons works out about 12.26:1...... pretty good but I think they might need valve reliefs cut.
SR16/20 head with 2 Litre crank, rods and N1 pistons works out about 13.1:1....... not so bad.
SR16/20 head with 2 Litre crank, rods and SR16 pistons works out about 13.7:1....... not so bad
SR16/20 head with 2 Litre crank, rods and SR20VE 20V pistons works out about 10.73:1....... too low for my requirements. Not even sure if the 20V's can be used.
SR16/20 head with the 2 litre crank, rods and DE (flat top) pistons works out about 11.25:1......not bad in theory but would they need valve reliefs cut?
SR16/20 head with the 2 litre crank, rods and SR20VE pistons works out about 10.36:1...... a bit low but might be handy for a small turbo setup or low quality fuel.

Next I need to calculate howw much needs taken off the piston crown to get the c/r down to about 12.5:1. I'll update when/if I can get my head round it.

Any comments or corrections welcome.Also any data on any other SR piston crown volumes, if anyone has data on the CP 12.5:1's or DET pistons that would be particularly helpful.