Piv

I've made some research of few forum and every time on the question : What the max overbore can I get from a B18C ? the answer was 82mm is the limit don't go above

But nobody actually explained why, I know the sleeve can be weak at some point but there's still plenty of room, and for a B18C All motor I would though it would be safe enough to go 84mm

What do you people think ? And what's the difference between a B18C type R bore at 84mm and a B20B std ?

Thanks

Romain/Piv

EdSales

The Sleeves are different between the B18 and B20. The B20 is just a one peice Sleeve I beleive.

mouab18c1

iTrader: (5)

All GSR blocks bored to 84mm are sleeved.

Piv

Ok, but why ? Does the sleeve actually crack ?
Any people actually tried it ?

No argue here just trying to get the right info

ruffrhyder

iTrader: (1)

A buddy of mine went 83mm on stock sleeves. Hasn't had a problem yet. Proper tuning is key.

95skunkedgsr

take your head off the motor and look at the sleeves from the top and your will know why

mouab18c1

iTrader: (5)

The OEM sleeves will get thinner the more you bore it out.

fv8s

i honestly wouldn't go anymore than 82mm. the larger the bore, the thinner the wall, the weaker the sleeve

Piv

Ok, after comparing B20 and B18C the sleeve will obviously go much too thin compare to a standard block !

I'll stick to 82mm and be safe

airmaxbri

Thinner = weaker = less material to dissipate heat.

I was told 82mm is the limit also.