I'm not quite sure if people that are running big bores are doing this and what their reasoning is. Are you people running stock size combustion chambers or are you opening them to the bore. My thought is there will be clearance issues with high compression and and big bore.

 

85mm IB Wiseco Super Dupers and no clearance issues. 86mm IB Wiseco Ultimates and the combustion chambers were opened slightly at the ends, just to be safe.

 

Are you running a pr3 or gsr head?

 

PR3 with welded combustion chambers-looks pretty much like GSR combustion chambers.

 

85mm bore, chambers opened up to 85mm. JE 12.0:1 piston and PR-3 head. I wish i would not have done it. I want my missing compresion back. On the flip side though, this motor is very strong and I have zero complaints other than a little bit of missing static compression.

 

do most setups that use a 84.5 bore or greater have to open up the chamber to match the bore size?

i'm a little confused on this concept because i hear about crvtec getting put together without having done much of any machine work

even in honda tuning when they did the 13 sec integra articles they didnt do any machine work to the head

what are the pro's and con's to a setup of that sort

 

84.5mm bore 13.4:1 CR and we didnt open up the combustion chambers.

 

yeah, i just don't want any detonation if the piston deck is like .010 inch from the head.

 

84.5 with opened chambers.. ~11.5:1, need more compression, bigger pistons!