i have a fully built sleeved b16a engine, inside cylinder one the wall was scarred. i have a question im hoping someone can answer, i had cp piston sc7000 series 81mm 9:1 comp. im going to go with a 84mm cp piston to be sure the scar will be gone once its bored. will i have to get a retune if i change the piston? that may sound like a dumb *** question lol but i need some good advise. thanks .. jason

 

not necessarily a full retune,

just a touch up

 

ok thanks man

 

i hope you arent just putting in one 84mm piston are you. i got confused reading that.

 

that is a lot more bore...

i would get a retune. more timing would likely be in order.

 

how much boost?hp? u might need to got with a looser p2w clearance so u dont scar ur walls again..cp recomends.0035 go with .0040 if u are over 500hp..

 

I'd go 83mm bore just incase something goes wrong again, you'd have more to bore out before your too big for boost.

 

The block is sleeved. 84mm will be just fine.


And yes you would need a retune. Whether you call it a touch up or a full retune, you will still need to have the tune change for the displacement/compression change.

 

NO ****! I said I'd go 83mm just in-case something goes wrong again. Then he'd still be able to go 83.5mm, 84mm, and 84.5mm before your stretching the limits of the sleeves. I ran 84.5mm and had a piston to wall issue and had to start all over again. That's why I'd go 83mm just so you don't have to worry about having to re-sleeve the block if something goes wrong.

 

the engine made 389hp @17psi on pump 91. i just ripped apart the block and its ordering time..so for sure i'll have to retune? even if im keeping the same compression and just going with 84mm? im not trying to come off cheap its just that the tune i have is great. that really blows lol . thanks for the replys guys ! help me!!