Engine displacement

[KnifeEdge_2K1]

Engine displacement is the volume of the number of pistons undergoing combustion at any given time right?

so on a 4 cylinder engine the displacement is the volume of 1 cylinder, on an 8 cylinder engine the displacement is the volume of 2 cylinders.

[Matra et Alpine]

Originally Posted by KnifeEdge_2K1

Engine displacement is the volume of the number of pistons undergoing combustion at any given time right?

so on a 4 cylinder engine the displacement is the volume of 1 cylinder, on an 8 cylinder engine the displacement is the volume of 2 cylinders.

No.

Displacement is the total of all cylinders swept volume.
For those who need to calculate these things - especially when over-sizing pistons - might need this .... http://www.bgsoflex.com/displacement.html

[KnifeEdge_2K1]

Originally Posted by Matra et Alpine

No.

Displacement is the total of all cylinders swept volume.
For those who need to calculate these things - especially when over-sizing pistons - might need this .... http://www.bgsoflex.com/displacement.html

oh crap sorry i was squaring the diameter not the radius ... that sucks im an idiot, alright man thanks

[KnifeEdge_2K1]

im trying to find a way to lower compression ratio so you can run higher boost, i know a thicker head gasket will do but i was wondering how much thicker, when i was doing calculations for the piston volume with the bore and stroke i mistook the bore for radius but in fact it is diameter ... im so stupid

[DodgeNitroBIRM]

I think you can use dished pistons to lower compression ratio for higher boost. Don't take my word on it, though.

[fpv_gtho]

i'd go for the dished pistons for a substantially lower compresion ratio, but if its only a small decrease, then a thicker head gasket should do it

[GTR Dreamer]

http://auto.howstuffworks.com/engine6.htm

try that

[Matra et Alpine]

Originally Posted by KnifeEdge_2K1

im trying to find a way to lower compression ratio so you can run higher boost, i know a thicker head gasket will do but i was wondering how much thicker, when i was doing calculations for the piston volume with the bore and stroke i mistook the bore for radius but in fact it is diameter ... im so stupid

The problem in trying to use thicker head gaskets is that with higher cylinder pressures they are more likely to fail being thicker unless you do seriosu engineering and fit wills rings or similar.
Do you plan to DIY this or use over the counter parts ?
If the latter get comp dished pistons - with comp rings.
If the former .... you can also reshape the combustion chamber in the head. That depends a LOT on the head tho and whilst not to difficult ( and enables you to port and polish it at the same time ) it often involves a few knackered heads before you get it right. BL 12G295 head, been through a few of those in my time

[NAZCA C2]

Like several other people have already said, dished pistons are the best way to lower the compression ratio.