Ratio
Degrees
Compression
Start
Degrees
Compression End
Degrees
Total
Cubic
Inches Start
Cubic Inches
Finish
Date
 
8.85 : 1 a, b
273.2
352.5
79.3
52.39
5.92
10-Feb-06
 
12.00 : 1 b, c
246.8
352.5
105.7
71.04
5.92
22-Aug-08
Mathematical
Measurements
12.69 : 1 b, c
246.8
352.5
105.7
71.04
5.6
29-Aug-08
Physical measurements
12.35 : 1
246.8
352.5
105.7
71.04
5.76
30-Aug-08
Average:  (12.00 + 12.69)/2
= 12.35
1 Degree = .6721 inches.  Based on the current engine housing size.
a - calculations from 2006. Original
b - piston plate face aluminum inserts details before 22-Aug-08
c - exhaust ports tot he right.  Moved CW 27.75 deg.  Note that the piston plate seals or seal is CCW past
the ports for compression start.
Example;  Otto, ICE:  If the volume of the cylinder with the piston at BDC is 10 times greater than the volume of the combustion
area  with the piston at TDC, then 10 units of volume get squeezed into 1 unit of space, and the compression ratio is 10.0:1.  
http:/www.carcraft.com/techarticles/calculate_compression_ratio/index.html
TRE COMPRESSION RATIOS updated 9/1/09
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