Help me find my compression ratio!
 

Hey guys, I am in the middle of trying to find out my CR so I may order an ECU with a basemap.

I am currently using this calculator: http://www.c-speedracing.com/howto/c...c/compcalc.php

My block has been decked and honed to stock specifications. The pistons are Wisecos model number K541M81. Here is all the info I can dig up on them:

K541M81 81.00 / 3.189 Std. 3.504 5.394 1.181 45 -12 .028 .020- 8.347 8.3-8.6 .827 8100xx 268

I also have Eagle H Beam connecting rods. Everything except the pistons should be stock. Which shold make this easy, except I'm unsure about one thing. When I get to pistons deck height do I imput it in as -.020 or .020? I know it seems stupid, but I want to get this correct. Because each of those settings changes my CR a lot. I get 8.2:1 and 8.8:1. Let me know please.

Re: Help me find my compression ratio!
 

9;1 or 9.5;1

Re: Help me find my compression ratio!
 

the number you need from the pistons is the dish or dome in cc's...you just posted a bunch of numbers so I am not sure which it is.

Re: Help me find my compression ratio!
 

Lmao, sorry bout that. The dish is "-12"

Re: Help me find my compression ratio!
 

yeah you're sitting right around 9:1 ...perfect.

Re: Help me find my compression ratio!
 

Ok I left out a lot in my original post.

Engine B18A1 (81mm bore - 89mm stroke)
Head B18A1 (45cc per cyl)
Piston - Other (-12)
OEM 3 layer gasket
Piston to Deck Height <-- Where I am confused. If I imput ".020" in I get 8.2:1 CR. If I enter in -.020(shown as .020-) then it comes out to be 8.9:1. I'm sure this should be obvious to me, but what is it? LMK thanks.

Re: Help me find my compression ratio!
 

http://www.wiseco.com/PDFs/Catalogs/SC06_AcuraHonda.pdf

So 8.3:1 CR is correct.