I was kind of looking for a little more displacement out of my LS block. I was wondering if I bored it out to 82mm would I risk cracking the stock sleeve? Or am I safer just sticking to 81.5mm?

Setup
LS block
Rs machines PR3 pistons

Head
98 spec type R head (not ported)
Jun valvetrain
Blox type B cams (tuner series)
Aebs intake manifold (portmatch to TB)
PP 68mm tb
hytech replica headers

Tranny
b16a2
ITR 4.7 FD
Obx LSD

Shooting for 210whp?

 

82mm sleeves are fine for 500+whp

 

You cannot bore stock sleeves to 82mm safely. 81.5mm is fine but not 82mm

 

82mm is fine, plenty of sleeve to work with. most piston mfgers even mass produce pistons for this. If I'm not mistaken I believe all a b20 block is, is a b18a/b block with 84mm bore, but correct me if I'm wrong

 

ure wrong... very..

 

with proper tuning, i think your sleeves should be fine...had my 12:1 c/r 82mm gsr for about 10/11k now and it still holds good compression and no problems whatsoever

 

yea like they said it should be fine but thats the biggest bore i would go. and also going from 81 to 82mm isnt really upping ur displacement much at all i dont see it making much of any dif. ide prob do 81.5mm just for safety. but shouldnt be an issue.

 

Going from 81mm to 82mm will net you 43.53cc over all 4 cylinders. Not a huge gain in displacement, but if it can be done reliably it's still a gain.

 

Yes, I would call a 23% gain in displacement "worth it".

 

My math above was a bit off for the OP's specific engine. I'm not as familiar with the B series stuff. If you went out to an 82mm bore it would actually be a 46cc increase over the 4 cylinders.

If he was to increase his stock 1834cc, 81mm bore engine to 1880 82mm bore, that is an overall displacement increase of 2.5%. Not sure where you get the 23% displacement gains but I like your math better than mine.

 

Thanks for the response guys! I had a another question that i always been wondering about. Does the type R head comes mild ported form the factory?

 

I forgot ze decimal, her docterr

 

One decimal place.. tiz a goud sing ve are not making z next generation rocket, yes!

 

get a block guard...should help.

yeah, bare itr heads are mild pnp. b16/b17 bare heads are the same as itr they just dont have the mild pnp.

 

it is only cleaned up near the valve seat, thats it.

 

If i wanted 2 bore an ls 2 a 2.0 what mm pistons will i have 2 put in 2 do so? (Noob)

 

84.5mm bore x 89mm stroke will give you a 1996cc (2.0L) displacement. Sleeves will be required to reach that bore in an LS block.

 

Thanks alot.