B18Sleeper

ok i was lookin into pistons and i was wondering what the difference is when you go with a bigger piston? i seen cp pistons 81mm cr 9.0:1 and then 84mm cp pistons with the same cr. what is the advantage or disadvantage to a better piston? will it help or make any difference on a FI car? thanks

B18 CYA

81 or 84mm doesnt mean which ones better. the bigger the displacement, the more torque you'll make. so pretty much the bigger the pistons, the bigger the bore you have and the more torque you'll get

B18Sleeper

ok so i should get mine bored out as big as i can with a 9.0:1 cr? which will be 84mm? that will make higher torque numbers and not a higher hp number.

B18Sleeper

am i off track or on the right one here?

B18 CYA

if u do that, you will have to sleeve your block. 84mm bore on stock sleeves will crack in no time

B18Sleeper

i was planning on sleeving it either way with daron mids

B18 CYA

then go with 84mm

B18Sleeper

is it stupid to sleeve, bore, and port/polish a motor when your build is for 400 to 450whp?

B18 CYA

for 400whp i wouldnt port/polish ... plenty of people making 400-450 without port/polish. and if you want to make 400+ whp id sleeve for safety...especially on 84mm bore

B18Sleeper

ok would u happen to know a good place to send my motor to get bored? i tried the search but it said the past 2 days that its temporarily unavailable or something.

B18Sleeper

oh and how much would i have to get it bored over to achieve 84mm? and i was lookin at the pistons i want CP and the place i was goin to get them from only carry 83mm 9.0:1 pistons so what would it take to achieve 83mm bore

Riceintegrars

hopefully i know wat im talking about

when ur overboring, ur thining out ur cylinder walls, so they become weaker, but since ur getting them sleaved, its no problem.

when u go to get ur block bored at the machine shop, they usually require u to bring ur pistons aswell, so they know it will fit.

B18Sleeper

sorry my question was a little confusing..i want to know like when ppl say i bored mine .20 over...what will mine be bored over to get 83 or 84mm?

SOHCD16y8

every .020 overbore is .5mm

B18Sleeper

so it would be a .12 bore over? thanks man

B18Sleeper

anyone know a good place to send it too? or would it be just any machine shop can do it? what are the running price for boring something .12 over?

NJIN BUILDR

OK my head is spinning.Talk milimeters or inches.Standard bore is 81mm or 3.189".Plus .5mm is .020" (81.5mm or 3.209").To have the bore 84mm will require sleeving,thats too big for the stock sleeves.
Glenn

B18Sleeper

yes and i am goin to sleeve it with darton mids.

SOHCD16y8

Not to be a dick but it seems like you are rushing into things and not planning it out very well. Think it through and do some research before buying this and boring that. In the matter of a day you went from not knowing anything about bore and sleeve to deciding to sleeve and bore to 84mm. Just some good advice to think about. The smallest mistake can screw your whole build.

B18Sleeper

yes and my build wont begin for another 5 months. which is why i am asking questions and tryin to learn now. just cause i say something now wont mean i will do it when i start my build.

B18Sleeper

thanks though..

SOHCD16y8

Just trying to help, dont want to see people making simple mistakes. But if it does come together as you are planning it will be a very strong car.

B18Sleeper

i hope so, i am planning this out completely. i mean i wanna go into it knowing what i want and what i need. i plan on parking my civic and pullin my motor in about 2 months but i am goin to do the body work first then start on the motor. it gives me more time to get all my motor in check. thanks for hte help tho