Civic EG

how much power can stock sleeve handle on a gsr with a piston and rod combo some1 told me i could get 450hp safe on a b series

That's about as much as anyone should really try to push stock sleeves but there's always gonna be cases of people making much more and people who've blown out cylinder walls on 200whp NA setups. For about $300 you can send your block to CNC for their cylinder support system that's good to 700hp all day. Just stay away from block guards!

yea alot of ppl have been saying stay away from block guards why is that ? and if i send it to cnc they will re sleve it ? or what do they do to it ?

Block guards do one of two things, either crack sleeves or egg the walls. CSS is what a block guard should actually be, it completely lines the entire walls and has a deep section that stabilizes the walls. It's a little more than $300 tho after shipping and then the block MUST be decked (not included in price) and its recommended for the block to be bored as well. Only down side is that it sacrifices some coolant capacity and requires atleast a dual core rad (any will do just make sure a shroud is used) so I would assume in a humid region you would need to double up on fans as well.

But to answer you original question yes stock sleeves have been known to handle around 450 before it flies apart but many factors play into that, if you never driven a fwd car of that power or close to it then I wouldnt suggest going over 300-350 which stock sleeves can handle safely AFTER A TUNE NOT A BASEMAP.

IM sitting at 390 with a stock sleeve b16a

so CNC cylinder support system is it a block guard that the put in or is it some sort of sleeve ?