Hey,
I have some JE 9.8:1 pistons for a GSR, if I stick them in my b16a2 with stock headgasket, this shop owner says I will be at around 9.3 - 9.4:1 compression ratio, but then reading H-T forums, it seems I will be at 8.8 - 8.9:1. Which will I be at? 8.8:1 is too low IMO for a daily driven street car seeing about 14 psi of boost. thanks!

 

Math is your friend.


Compression Ratio Formulas
GV (Head Gasket Volume) = Bore(in) X Bore(in) X 12.87
X (Head Gasket Thickness in Inches)


DV (Below Deck Volume) = Bore(in) X Bore(in) X 12.87
X (Inches Below the Deck)


HV (Head Volume) = CC's


VV (Dish, Valve Pocket, Dome Volume) = CC's
(Minus for dish or valve pockets, Plus for dome)


PV (Volume displaced by Piston) = Bore X Bore X Stroke X 12.87


Compression Ratio = (GV+DV+HV-VV+PV) / (GV+DV+HV-VV)

Cubic Inches = Bore x Bore X Stroke X Number of Cylinders X .7854

Convert Cubic Inches to CCs = Cubic Inches X 16.386
Convert Cubic Inches to Liters = Cubic Inches X .016386

Engine in Liters = (Bore(mm) X Bore(mm) X Stroke(mm)
X Number of Cylinders X 12.87) / (16386 X 1000)

Engine in CCs = (Bore(mm) X Bore(mm) X Stroke(mm)
X Number of Cylinders X 12.87) / 16386

Convert CCs to Cubic Inches = CCs / 16.386
Convert Liters to Cubic Inches = Liters / .016386

 

lol..too bad I suck at math.

 

Maybe this might help.
http://www.c-speedracing.com/h...c.php

 

well I just did it, its 8.82:1

bust..that seems kind of low. well, how many psi do you think I can run on 8.82:1 with eagle rods and stock sleeves?