I searched but came up empty. I would like to know what is the best pistons to use with this set up? I want to keep my compression ratio at most 11.5 since I live in cali and we have crappy octane. So what piston would yield me the comprassion I want the JDM P30 or USDM P73? Is it true that the GSR head will add .2 compression to the B16a2's 10.2 compression? Please help me out since I need to order pistons within the next two weeks since my head come in next week.

 

dont use p73 pistons!!! they will lower your compression. The pr3 and the p30 are very similar but if i was you i will put some ctr pistons and will bring your compression to 11 with the gsr head.

 

so with the CTR pistons I will be at an even 11.0 compression? thats great I think I might look into the ctr pistons now since that kind of compression is just perfect for a cali car. Any more input would be appreciated.

 

i believe with ctr's itll bump the compression a lil higher of 12.5.1 with a gsr head, about 11.3:1 with itr's, about 11.6. with p30's just my .02 cents, i say go with the p30s or pr3, basically alllmost the same


Modified by StrokeDC2 at 1:52 AM 6/10/2006

 

thanks man good thing you mentioned that about the CTR's so I guess I'll go with either ITR's or P30s. How safe or reliable would 11.6 compression be with 91 octane cali gas?

 

no problem, it'll be definitely be safe with a good tune

 

but remember!!
he is using a b16a block not a b18

 

So which is it?

 

so ur sayin the compression of a motor depends on the block itself? basically compression is determined by bore, and stroke, and piston, but by his application of just stock b18c, my estimate of each pistons above is a good estimate of how each piston will yield its compression

 

Youll be right around 11.1 with the ctr's. Thats fine with a good tune on 91 octane.

 

also as YOU stated about pcts or ctr piston is gonna hold about 11.1 compression,you surely dont understand wat compression will come out with ctrs or itrs or p30s with a gsr head

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StrokeDC2 &raquo;</TD></TR><TR><TD CLASS="quote">so ur sayin the compression of a motor depends on the block itself? basically compression is determined by bore, and stroke, and piston, but by his application of just stock b18c, my estimate of each pistons above is a good estimate of how each piston will yield its compression</TD></TR></TABLE>

The b18 series blocks have a taller block and a consequently longer rod. CTR's in a stock GSR would yeild around 13:1 compression. CTR's in a B16 block with a GSR head would raise your comp to around 11:1 due to different deck height, stroke, pistons to deck height etc. etc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StrokeDC2 &raquo;</TD></TR><TR><TD CLASS="quote">also as YOU stated about pcts or ctr piston is gonna hold about 11.1 compression,you surely dont understand wat compression will come out with ctrs or itrs or p30s with a gsr head</TD></TR></TABLE>

I dont know if this was directed at me, but i completely understand. You have to factor in stroke, piston to deck height, combustion chamber volume. Have you ever calculated CR before yourself, or do you just use C-Speed?

 

no it was direct at ruben19

 

If you want an approximation, its 11.7:1 figuring in the compression height and dome of the pct's. Fine with a good tune on 91. Good luck with the build.

 

will adding a B17 crank and rods affect the engine compression at all or will it remain the same?