hi guys im building a b18a1 motor for boost and not sure what pistons or ratio to go with??? I know stock is a 81mm I was thinking to do a 82mm je piston with a 9.5:1 ratio with eagle h beam rod and a eagle forged crank with acl race bearing looking to get about 350hp head will have a brian crower stage 2 turbo cam supertech valve train my turbo is a turbonetics t3/to4e ceramic ball bearing turbo ........ so what my question is do these pistons sound good for this build is it reliable for 16psi

 

You should read more. Eagle cranks are overpriced, and not worth it unless youre pushing 1000+
I havent heard of anyome breaking a crank.

82 is a bit big for stock sleeves, stick with 81.5 and that compression is ok. Im pretty sure the stock head and cams will do 350, but those cams will be fine.

Psi doesnt matter, itll take what it takes. It might take more it might take less. Go to the forced induction section and read the ls turbo thread

 

I'm running 9.8:1 with boost using 83mm pistons in a block that was 81mm stock (b20a5 block). my last setup using the exact same configuration (except 9.5:1 compression) was making close to 400tq/400whp and held up fine for 130k miles, most of which was fairly heavy abuse. was/am still using stock head bolts and crank bolts too.
long as the block is closed deck it'll be fine running 82mm. 81.5mm will be a tiny hair stronger though

 

Prelude engines have almost zero in common with open deck integra engines. 83mm on an ls block would basically make them paper thin, and shatter.

82mm is max on b18a/b/c block. 81.5 is the biggest i would personally run boosted

 

then apparently you don't know much about the 88-91 prelude. the blocks and heads are nearly identical to LS motors in almost every way. but just different enough for the parts to not be compatible with each other.
boring an 81mm sleeve to 83mm is only thinning the sleeve thickness by 1mm, and to 82mm is only thinning the sleeve by half a millimeter. that isn't squat when you're talking about a 6mm thick steel sleeve with an additional 5-6mm of aluminum behind it.

search pics of the b20a5. if you didn't know any better you'd think it was an LS motor

 

they're not the same. no you cannot bore an ls motor to 83mm. stop talking about things you don't know. you'll crack a sleeve in no time even if you could get it to 83mm.

 

I'm looking at an open b18a1 block right now, and the sleeve thickness is exactly the same as what my b20a5 block was before I bored it over 2mm. it will hold, just use a block guard if you're so worried about it

 

Well then, why doesnt everyone punch em out to 83?
You know at 81mm the bores begin to have issues holding power at 500+hp

Now imagine makong them thinner.

Also, the sleeve thickness between the bores is reduced by 2mm. Even with a block guard, theyre still weak.

I wouldnt even run 82mm boosted

 

to be honest, I don't know why more people don't do it. I'd guess it's because no one wants to be a pioneer to determine just how strong the stock cylinders are when bored over. I've always been a pioneer like that, for personal knowledge, and public knowledge. why else would I be sharing the other info in this thread?

besides, iirc, the 500hp+ issue on stock ls block has nothing to do with sleeve strength, but rather has to do with cylinders shifting and cracking due to lateral loads and being open deck. not expansive loads ballooning the cyls.
and you must remember too, the steel sleeves have nothing to do with the lateral structure of the cylinders, as the steel is only a sleeve embedded into the alum part of the cyls, it is not tied into the block's actual structure in any way.

boring over only reduces expansive strength by a small margin. rough guess, it would limit the cyl strength to around 400-450.
but then again, I ran my 83mm setup at 400tq/400whp for quite a while too, and had zero issues there as well. my block is closed deck though.

bore center to center is identical in my motor as an LS. zero issues. hell, I even had a boost spike at one point where boost went 6psi higher than it was tuned for and 6psi higher than the map sensor could read. It ran about 5 degrees too much timing, and low 13's for af. I hammered the snot out of it like that for a full day. cracked a ringland in the process, but guess what saw zero damage? the block which was bored from 81mm to 83mm.