Ok so the shop had to over-over bore and now I'm looking at going 81.5-82mm on a B18C block. I will mate this to an ITR head, and run JUN III cams. I am lazy and did a fast search, but didn't see much..

Can I bore the B18C to 82mm AND run 13:1 compression w/o sleeving? The bottom has been balanced, and we're running stronger rods, ACL bearings, etc. I'm hoping that I can get away with this, as I want to get this motor in an start to hit 12s, plus make some locals quiver in terror at the amazing results.

P.S. what can I expect the difference in torque to be from 81-82mm? I would guess about 2 ft/lb

 

81-82mm seems a little big, maybe its just me

 

Well if a b20 block can go 84mm with stock sleeves then i dont see why not,it will definately be weak though.

 

no one seems to have any probs w/ 81.5mm, I'd think 82mm max...I've been told in an all-motor setup you can go as big as 84mm BUT you shouldn't do more than 11.5-1CR...this seems to be the downfall w/ a lot of B20 setups, too much pressure on thin cylinder walls, I'd think at 82mm the CR you're talking about would work. Good luck

 

I wouldn't go beyond 81.27mm before the .25 overbore.. That's max. service limit on the Manual. If you wanna go bigger, I suggest you get it resleeved and get custom pistons. You can do whatever you want. It all depends on your wallet. Plan out what you want to do and check around diff. machine shops. You have to find a machinist that can hold really tight tolerances. Do some research before you go to a machine shop, so you don't sound like a moron when you talk to them. The more idiotic you sound, the more they'll grip you. I have a badass machinist and he's road racer............. just my 2 Cents

 

I thought 82mm was pushing it also... But I don't know. If I can't run 13:1 then what would be the highest I could go? I'm not really wanting to kill the motor that fast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J2turbo21 &raquo;</TD></TR><TR><TD CLASS="quote">Well if a b20 block can go 84mm with stock sleeves then i dont see why not,it will definately be weak though.</TD></TR></TABLE>
b20 sleeves arent just overbored ls sleeves, theyre totally different. i would sleeve it, for 750 you cant go wrong...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiR-DC2 &raquo;</TD></TR><TR><TD CLASS="quote">no one seems to have any probs w/ 81.5mm, I'd think 82mm max...I've been told in an all-motor setup you can go as big as 84mm BUT you shouldn't do more than 11.5-1CR...this seems to be the downfall w/ a lot of B20 setups, too much pressure on thin cylinder walls, I'd think at 82mm the CR you're talking about would work. Good luck</TD></TR></TABLE>
max with sleevs is 87 and you can run 86 and 13:1 compresion on 93 octane..

 

With stock sleeves I wouldn't bore any more than you have to at the most. If you want any more than about 81.5 I would have it sleeved, if not you are just in for problems.

 

That's what I was afraid of... I didn't really want to sleeve this block.. but it's sounding like that's what I might have to do... Could I bore it to 82 and run a lower compression?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridvteceg &raquo;</TD></TR><TR><TD CLASS="quote">
max with sleevs is 87 and you can run 86 and 13:1 compresion on 93 octane..</TD></TR></TABLE>

I'm aware of this, I was talking about w/ the stock sleeves, it didn't sound like he wanted to spend the $$$ on resleeving.

 

i was relaying that to the general public not you, so dont get offended.

 

I wasn't sorry I sounded like it