ok soo.... i currently am running a bone stock b18b1 motor on 10 pounds of boost. i also have a b16a block from japan with a stock bore of 81mm. i am wondering if it would be safe to increase the bore to the 84mm to make it the same as an ls block. i am going to build the b16a block for a turbo setup with an 8:1 compression, and want to keep the same bore as the ls. i am also wondering if the blocks are the same, but maybe the ls has thinner sleeves because of the bigger bore? and the b16a has thicker sleeves because of the smaller bore? thus, boring the b16a to 84mm would result in the exact same sleeve thickness as a b18b1 ls block?? anyone with any ideas please post. im lookin to run no more then 18 to 20 psi on the stock sleeves. i am not going to have it resleeved. anyone else ever bore a b16 block to 84mm with out resleeving it?

 

You are truly confused about bore sizes.Stock ls is 81mm just like a b16.Max recommended overbore with out sleeving is 82mm.

 

maybe i can just increase the stroke to pick up the extra cc that i am going to lose by switching to a b16a block??

 

so youre saying the b18b1 gains its extra cc's from the longer stroke? if this is so i could just run ls rods in my b16a block correct? they should work with the crank right?

 

no no no
the difference between the blocks are
b16 has a shorter deck height there for you cannot use the ls rods..(unless you have custom pistons).. and i do think the b16 crank would work with the ls rods..
the b18b block has the same deck height as the gsr and type-r do but the
b18b has a longer stroke.. all the b-series blocks have the same bore except the b20 blocks which come with a 84mm bore ls rods and ls crank.
hope this helps you out..
and no you can't bore it out to 84 with out sleeves..
just keep the ls motor sleeve it and then boost 18-20 lbs thats with sleeves and pistons of course

 

well i am stuck here, my b18b1 is currently in use in my daily driver, and i have the b16a block already apart, cleaned and honed. if i decide to build the b16, and run anywhere from 15 to 20 pounds of boost, am i going to be at any major loss of power compared to building the ls block? its about a 50 cc per cylinder between the 2 blocks.