whats the diff. between like 8:5:1 or 9:0:1 or other ones and which is better for performance? also whats the bore do and what is it ?

 

those are compression ratios, its basically the hight of the poston, it depends on your setup for which is better. high compression for n/a or non turbo motors and low compression for turbo motors.

 

the compression ratio is not the height of the piston. the compression ratio has NOTHING to do with the height of a piston.

compression ratio - It is a ratio between the volume of a combustion chamber and cylinder when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The higher the compression ratio, the more mechanical energy an engine can squeeze from its air-fuel mixture. Higher compression ratios, however, also make detonation more likely. Due to pinging (detonation), the CR in a gasoline/petrol or LPG or CNG-powered engine will usually not be much higher than 10:1. In engines with a ping sensor and an electronic control unit, the CR can be as high as 12.5:1 (2005 Audi A6 3.2). In a turbo charged or super charged engine the CR will be around 8.5:1
In a diesel engine the CR will be 20:1 and higher.

 

and another thing....if you have 5 questions that you need to ask, please ask them all in the same thread. do not start 5 different threads.

this is all you have to do....

"i have a couple of questions...

1. ....
2. ....
3. ....
etc..."

 

I dont ask them all in the same thread because when i do people answer the first question one and not the other ones. I asked about the bore and no one answered it yet.