Using Steve's Formula - bolded values are my revised numbers.
Volume at BDC is (swept volume - pop up volume)+ flycut and ring land clearance volume + gasket volume + chamber volume.
Volume at TDC is (volume in gasket - pop up volume) + flycut and ring land clearance volume + chamber volume.
Volume of BDC over Volume at TDC is expressed as a ratio to one (xx:1)
Your bore is 87.00
Your Pistons are
86.15 above the top ring land and the top ring groove is
8mm down from the crown.
Your Valve Flycut measured volume is
2.1cc
Your Piston sits at 0.65mm plus deck
Your Combustion Chamber measured volume is
36cc
Your head gasket is going to be 1.5mm compressed and has an inside fire ring diameter of 87.2mm (assuming a Felpro 21195-PT2)
So lets do some math...
Swept Volume of the cylinder.
Pi x R squared x Stroke
3.14285 x (43.5 x 43.5) x 67.4
3.14285 x 1892.25 x 67.4
400.831cc
Volume of the piston 'pop up'
3.14285 x (
43.075 x 43.075) x 0.65
3.14285 x
1855.4556 x 0.65
3.790cc
Volume of the head gasket.
3.14285 x (43.6 x 43.6) x 1.50
3.14285 x 1900.96 x 1.50
8.961cc
Volume of the ring land clearance.
[3.14285 x (43.5 x 43.5) x
8] - [3.14285 x (
43.075 x 43.075) x
8]
[3.14285 x 1892.25 x
8] - [3.14285 x
1855.4556 x
8]
47.576cc - 46.651cc
.925cc
and then put these numbers into the equation,
Volume at BDC = (400.831 -
3.790) +
2.1 +
0.925 + 8.961 +
36 =
445.027
Volume at TDC = (8.961 -
3.790) +
2.1 +
0.925 +
36
=
43.271
Static Compression: V at BDC / V at TDC (
445.027 / 43.271) =
10.285:1
note: there is a chamfer at the top of the piston that is not accounted for - actual compression will actually be less. Not sure how much less. Need to see if I can get the specs on that from Wiseco, I never measured the depth of the chamfer and the diameter of the crown inside the chamfer...