just got back from pure tuning in toledo. They claim that they've can run a forged piston in the h22 without sleeving. They make their own pistons, and they say that if they use a (softer,harder i forget which) alloy, that once heated the piston will not expand nearly as much as the other. They also use a moly skirt, the down side of all this is they don't have a local car to show it. They said that they sent otu a couple sets of pistons that are going to be used, so i will keep it updated

-seperate question, i can't find what the jun pistons are made out of, because they can be run in the stock sleeves with no problems, and at the same time what is it that makes a forged piston "non-compadable" with the frm sleeves?

 

maybe this helps. https://honda-tech.com/zero...age=2
edit: it does depend on the type of metal used...different properties cause the piston to expand and hit and score the wall causing damage.

 

is piston expandage the only reason that the forged pistons don't go well with the frm sleeves?

 

not really sure, i'm not an ME with metallurgy background...my best bet is yes, but I'm not sure, I would just always sleeve for a bulletproof engine.

 

thanks for replying, i'm going to wait for the other guys to put theirs in and see how they run, i'd realy like to just put pistons in and just get a really good tune instead of sleeving it