hey i wanna upgrade my internals on my gsr but first i want to know whats the difference between overbored pistons and regular pistons. thanks people

 

ones bigger in diameter.

 

just for a little more clarity...overbore is for situations in which the piston ring to wall clearance is no longer within spec due to honing etc.

 

so overbores r bigger pistons? do these pistons like induction?

 

do you mean forced induction?

and why would u raise the compression ratio if your going to use FI ?

stock bore is 81mm, one overbore would be 81.25mm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec_joe &raquo;</TD></TR><TR><TD CLASS="quote">hey i wanna upgrade my internals on my gsr but first i want to know whats the difference between overbored pistons and regular pistons. thanks people</TD></TR></TABLE>

first off... it's oversized pistons. there's no such thing as "overbored pistons". it's more like "overbored block". when you get oversized pistons you have to bore out your cylinder walls a bit wider to fit oversized pistons. the difference is that regular pistons are 81mm. overbored JDM's are .25 over, meaning 81.25mm. there are also other sizes larger, that's the difference. and it will help you raise your compression a bit.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec_joe &raquo;</TD></TR><TR><TD CLASS="quote">so overbores r bigger pistons? do these pistons like induction?</TD></TR></TABLE>

as previously stated, yes, and it's "oversized". overbored is for the cylinderwall in the block. and actually for the forced induction question, some oversized pistons are dished out in shape (for lower compression) and can accomodate turbo. other oversized pistons, definitly not. it really depends on the type of piston surface.

 

so whats the compression ratio on the type r oversized pistons bro? and whats the compression difference from the non oversized type r piston? if i want to go n/a, what do u suggest?