im confused on my compression. ive been told im gonna be 10:1 to 12:1 i dont understand how to calculate it out.

i have a b16a stock crank and stock rods. CTR pistons. the head hasnt been milled I dont think.

what compression can you safely run on 91 pump gas?

will aftermarket cams bump up the compression? im running blox type b cams, brian crower ss flat face valves.

thanks

 

anayone have any input?

 

Go to the faq's . The cr calculator is in there.

 

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/diy-compression-ratio-calculation-2476094/

 

http://www.c-speedracing.com/howto/c...c/compcalc.php

use that site and if you are tuning the car they can make it run on 91.

 

ok I need help im using this calculator

http://www.zealautowerks.com/bseries.html

b16a block, b16a crank, b16 head, PCT piston standard bore, b16a rods, oem 3 layer head gasket, the guy who ported my head told me to mill the head 20 thousandths ( havnt done it yet, is 20 thousandths labled .020"? )

max rotating rpm 8500

elevation 300 feet

if I calculate those and leave the milled section at 0 heres the results and the screen turns yellow.

static comp ratio. 11.91:1
effective comp ratio. 11.85:1

if I put .020 for milled the screen turns red
static comp ratio. 12.76:1
effective comp ratio. 12.70:1

 

it looks like it is yellow because the piston to deck is a -.07 and you might hit the head with the piston

 

oh ****. well what does the red mean lol. I didnt have anything taken off the head i just had it surfaced and im using a oem 3 ply gasket

 

with the one i posted it looks ok. u will have to clay the pisno to head/ valves to check and see if you have the room. i dont see y it should be a problem but have it checked and be save.

 

You should check with the shop that you had the head surfaced at to verify how much was taken off after it was surfaced.

I had my head rebuilt and surfaced and the shop I went to took roughly .005"-.010" off mine as was mentioned.

 

the ctr pistons are your problem, the dome is to big on the piston, there to much trouble, get some p30 pistons, mill your head 20 thou, and run a 2 layer head gasket, youl have nice compression, when combined with the flat face valves you already have, and youl have much much more piston to valve clearance, and will be totally fine with 91 octane

you dont need huge compression to make good power

 

I will check with them on that im picking it up after work

 

I could not have said it better.

 

I dont have the time or finances to pull the pistons out and buy new. if I have to do that i might as well scrap the build and run ericks racing pistons with an ls crank and ls rods

 

Might i mention, Cometic makes different thicknesses of head gaskets from .030"and up which might offer an alternative to help lower the C/R and make room for additional deck clearance if needed.

 

noted lol thanks i might look into getting one of those

 

i did my comp check using the zeal calc. and mine is 11.67:1 on a D. using pg6 pistons....i melted the pm7's i was running when the vtec solenoid froze open about 2 years ago. switched back to the y7 head and put the pg's in and it runs pretty good.