B16, B18, B20
User avatar
By kapow
#317737 Hey guys, I have

JDM B16 head
AUDM B18C2 block (oem crank and rods)
PR3 pistons with 1mm shaved off the top
Skunk2 Stage 1 cams

With the 1mm shaved off the PR3 pistons i'm hoping to get a similar compression ratio to a jdm ITR. I will be using the stock oem cam gears, so I won't be dialing it in. What would my compression be with this combo? Do you think I need to clay my motor? Any input I much appreciate it
User avatar
By asianrob
#317746 http://www.zealautowerks.com/bseries.html

from when i did it with what you have posted it showed around 12:35.1
User avatar
By kapow
#317868 Thanks Rob!
By bks84
#317883
asianrob wrote:http://www.zealautowerks.com/bseries.html

from when i did it with what you have posted it showed around 12:35.1


i dont know what benefits there are from shaving the tops of a piston, but if he did then his compression wont be 12:1.
User avatar
By kapow
#317888
bks84 wrote:
asianrob wrote:http://www.zealautowerks.com/bseries.html

from when i did it with what you have posted it showed around 12:35.1


i dont know what benefits there are from shaving the tops of a piston, but if he did then his compression wont be 12:1.


My engine builder thinks 11.5:1 is a bit high for my local gas, shaving 1mm off will get it to 11.3:1 - 11.2:1
By bks84
#317890 Friend of mine ran 12:1 built motor on 91 pump, I'm running 12.5:1 on E85, my old motor was 11.5:1 on pump. It all depends on what your octane level is and how competent your tuner is.
User avatar
By juls1488
#317900 if you want, you could take a look at the P73 pistons. theres two versions P73-A0(USDM B18C5 ITR) and P73-00(JDM B18C5 from ITR). less dome, but slightly higher compression hieght. and then depending on your headgasket thickness, you could get in your target comp ratio range without milling pistons.
just a thought!
User avatar
By kapow
#317911
juls1488 wrote:if you want, you could take a look at the P73 pistons. theres two versions P73-A0(USDM B18C5 ITR) and P73-00(JDM B18C5 from ITR). less dome, but slightly higher compression hieght. and then depending on your headgasket thickness, you could get in your target comp ratio range without milling pistons.
just a thought!


I actually couldn't find any jdm itr pistons anywhere, so had to settle for pr3. Close enough. But everything is all balanced, trying to build a similar engine to Spoons B18C