I have a '93 B18a1 engine on a '92 civic hatch. I just bought a '99 B16 Vtec engine but I wanna make it Ls Vtec-Turbo. So my question is which Pistons are better for Turbo application, B18A1 pistons or B20b pistons?? I'ma get rid of the B16 pistons cuz they aint no good for me for turbo... I saw some B20b pistons on ebay, some were with dome and some were flat head.

 

B20 pistons are a different bore than B16/B18 pistons, so they won't work without the block having been bored to match.

 

what about the B18a1 pistons? do I need to bore the block as well for them to fit? weather I have to bore the block to fit the B20b pistons in the B16 block or not which pistons are better for Turbo is my Q's....

 

No, B18A1 pistons will work without needing to bore the block. B18A pistons will make a ridiculously low compression number in an otherwise-B16A motor. (8.6, according to ZealAutoWerks compression calculator)
I'm going to let someone more knowledgeable answer your questions about which would be best.

 

b16a = pr3 and p30
b16b = pct
b18a/b = pr4 and p75
b18c = p72
b18c5 = p73

all are 81mm

b20b and b20z are 84mm.
does that help?

 

yes it does thanks!!!

 

hey I put the specs of putting Ls pistons in a B18a block and it didn't give me no 8.6 comp. I'm not sure where its read but here's what I got> piston to deck height -0.096 , effective comp ratio 11.86, rod stroke ratio 1.77 @ a max operating RPM of 8000

 

http://www.zealautowerks.com
use this to find what combo of parts will help you achieve your CR goal. Use the LS block with the b16 head, that'll keep you at 1.8 L.

 

ok I guess I'm gonna have to use my 1.8 block and do Ls Vtec that way, I thought I could keep it 1.8 using the B16a block if I were to put on a LS crank,LS Piston wit LS piston rods on that B16a block... Thanks for the Info by the way!!