Subject: How do you figure final compression ratio for supercharger applications?
Answer:
The formula is: FCR= (Boost/14.7)/1xCR FCR: Final Compression Ratio CR: Compression Ratio
Comp.Ratio Boost (in pounds per square inch)
2 4 6 8 10 12 14 16 18 20 22 24
6.5:1 7.4 8.3 9.2 10.0 10.9 11.8 12.7 13.6 14.5 15.3 16.21 17.0
7.0:1 8.0 8.9 9.9 10.8 11.8 12.7 13.6 14.5 15.3 16.2 17.0 17.9
7.5:1 8.5 9.5 10.6 11.6 12.6 13.6 14.6 15.7 16.7 17.8 18.6 19.5
8.0:1 9.1 10.2 11.3 12.4 13.4 14.5 15.6 16.7 17.8 18.9 19.8 20.9
8.5:1 9.7 10.8 12.0 13.1 14.3 15.4 16.6 17.8 18.9 19.8 20.9 21.9
9.0:1 10.2 11.4 12.7 13.9 15.1 16.3 17.6 18.8 20.0 21.2 22.4 23.6
9.5:1 10.8 12.1 13.4 14.7 16.0 17.3 18.5 19.8 21.1 22.4 23.6 24.8
10.0:1 11.4 12.7 14.1 15.4 16.8 18.2 19.5 20.9 22.2 23.6 24.8 26.0
10.5:1 11.9 13.4 14.8 16.2 17.6 19.1 20.5 21.9 23.4 24.8 26.2 27.6
11.0:1 12.5 14.0 15.5 17.0 18.5 20.0 21.5 22.9 24.5 26.0 27.5 28.9
Final compression ratios above 12.4:1 are not recommended for use with "premium pump gasoline."
The higher the final compression ratio, the higher the octane rating of the gasoline must be, in order to avoid detonation and serious engine damage.
Altitude plays an important role in determining compression ratios. If the altitude in the area where the vehicle is driven is significantly higher than sea level, then the compression ratios will vary. To determine the effects of the altitude on a calculated compression ratio, us the following formula: Corrected Compression Ratio = FCR - (altitude / 1000) x 0.2
top
|
