Re:zc d15 turbo
 

With stock pistons the thing would be slow as ----. 7.8 c/r NA.. now that would rock :-\ The ZC has a huge quench pad, hence why stock ZC/A1 pistons are domed.

Re:zc d15 turbo
 

I bet this becomes the next big LS/VTEC for the D series. Hell if you put some pistons and rods in there that thing could take 20 Psi. That would rock.

Re:zc d15 turbo
 

is that the stock zc/a1 cr? the engine i took the head off of had flat top pistons. is the deck taller on the zc? that would explain the pistons and the same stoke as the d 15. my d15 pistons had a flat top with valve reliefs.

Re:zc d15 turbo
 

d16a1 had two different pistons based on year.
you probably got the head from an 86-87.
the 88-89 had pistons like the zc.

Re:zc d15 turbo
 

7.8 c/r? was that for propane? i have never seen an engine other that marine or cng that had below a 8.0-1 c/r. the specs that i saw on alldata said 8.8-1. or is that with the head swap? because that just dont sound right. even on the head swap i figured at least a 9.0-1 with a .035" head gasket.

Re:zc d15 turbo
 

lol, 9.1:1? Yeah......

The DOHC pistons are domed with a larger chamber in the head. The SOHC pistons are flat with a smaller chamber in the head. Putting the flat pistons in the domed pistons motor would lower the ---- out of the compression. You put a DOHC head on a SOHC block which created a very large combustion chamber, lowering the compression.
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Re:zc d15 turbo
 

check the compression calculator. http://www.knology.net/~jediklc/D.htm

Re:zc d15 turbo
 

i got 8.5-1 c/r. it might be oof some because i got to find my spec sheet for my pistons, but this is what the stock setup runs.

Re:zc d15 turbo
 

What did you do differently than me because I got 8.25:1
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Re:zc d15 turbo
 

for the zc stock c/r i get 10.05 all the way down to 9.89 for the jdm setup and 10.55 to 9.98 for the usdm setup. the only variable that i changed was head gasket size.
this also restates what i said before in my h-t thread:

http://honda-tech.com/zerothread?id=...36969#12836969