hey guys..i have a b18c1 in my em1.im going na and going to put 12:1 compression ratio pistons in(for skunk2 pro 2).is it worth boring out to 82-83 then put the pistons in or if i leave it at 81 itll make the same power.also if i just put the pistons in do i need a whole tune..or wait till i put the s2p2 to do it alltogether

 

This needs to be posted in AllMotor.

 

If you are still using stock sleeves, my advice is to check the condition of the cylinders and only remove whatever material is necessary to eliminate any imperfections. This will leave the maximum amount of material in the cylinders for maximum strength. This will also leave you with room for a future rebuild if needed.

If you can get away with a hone only, then use standard 81mm pistons. If you need an overbore because of scratches or an 'out of round' condition, then bore it to one of Honda's overbore sizes. I don't think Honda even makes an 82mm or 83mm piston anyway, but aftermarket companys make an 82mm I have heard, and you can always have a custom piston made.

If you have aftermarket sleeves installed, then you can go with 84-86mm safely.

 

can stock even be bored to 83mm?

 

i am close to 13:1 with stock bore if you rehone and looks good then stock bore is fine IF not then at the max go up to 81.5 THATS IT 82 will not be a good d.d and good chance your cylinders will crack very quickly. just stay 81 because then if the block goes out you can rebuild it at 81.5

 

82mm is max.. i agree with dsracing stay 81mm..you have room for future honeing