hi, in a previous post i asked if it was possible to low comp my standard pistons for my s2.
lots of people have said it is ok.
but how much needs to be machined/skimmed off the top?
is it as simple as that?
hope you can help cheers

 

Depends how much of a problem do you have with knocking? Don't take any of you don't need to.
If you do take, take form the center only and not the furthest 5mm, because you don't wan't to shorten the distance fron the top of the piston to the first piston ring.

 

The amount you take off all depends on what CR you are looking to run.

If you go too mad skimming them it will be extremely dull to drive unless you're aiming for massive power and running a seriously big turbo.

And as Jesse says with regards to the area of the crown you skim.