COMPRESSION RATIO?
February 08, 2007
by: jovial_cynic
by: jovial_cynic
I'm trying to figure out how I came to a 9.5:1 CR calculation that I mentioned early on in this project.
Right now, I've entered in some stats into the CR calculator, with the following values:
Bore size: 87.75mm (Z22 bored out .75mm)
Stroke: 86mm (L20b crank)
Headgasket bore: 88mm (that's a guess; I just figure it's gonna be 1mm over the stock bore)
Compressed gasket thickness: 1.2mm
Combustion chamber volume: 42.5cc (A87 head)
Piston dish volume: -9.32cc (stock Z22e pistons, but they are shaved down a bit...)
Deck clearance: .2mm over deck (shaved down from .4mm)
The calculator says I'm going to run 9.98:1 CR, which is a bit higher than I originally calculated. Weird.
I had considered running a turbo or supercharge previously, but with the CR so high, I think I'll wait to do that with another engine in the future. 9.98 is probably just fine for an old NA datsun engine.
Right now, I've entered in some stats into the CR calculator, with the following values:
Bore size: 87.75mm (Z22 bored out .75mm)
Stroke: 86mm (L20b crank)
Headgasket bore: 88mm (that's a guess; I just figure it's gonna be 1mm over the stock bore)
Compressed gasket thickness: 1.2mm
Combustion chamber volume: 42.5cc (A87 head)
Piston dish volume: -9.32cc (stock Z22e pistons, but they are shaved down a bit...)
Deck clearance: .2mm over deck (shaved down from .4mm)
The calculator says I'm going to run 9.98:1 CR, which is a bit higher than I originally calculated. Weird.
I had considered running a turbo or supercharge previously, but with the CR so high, I think I'll wait to do that with another engine in the future. 9.98 is probably just fine for an old NA datsun engine.