| |
The compression ratio of your engine has a direct relationship to how much boost you can run. If you have a high compression ratio, such as 9.5:1 or 10.0:1, you will only be able to run a small amount of boost. The compression ratio that is built into your engine is called "static compression." When you combine the boost you are running in conjunction with your compression ratio, the result is known as the "Effective Compression Ratio." You can find your static compression ratio on the left side of the chart. Then read across to the right under the boost you want to run and the number in the box will be your "effective" compression ratio. Experience has shown that if you attempt to run more than about a 12:1 effective compression ratio on a street engine with 92 octane pump gas, you will have detonation problems. To some degree, this can be controlled with ignition retard devices, but we do not recommend that you set up your engine and supercharger to provide more than a 12.0:1 effective compression ratio. Use this formula to calculate the effective compression ratio for your individual engine application. Effective compression Ratio (ECR) = [(Boost / 14.7) +1] x CR
To compensate for altitude when computing desired "effective compression ratio" use the following equation: Corrected Compression Ratio - ECR - [(Altitude / 1000) x 0.2]
|
||||||||||||||||||||||||||
STATIC |
PUMP GAS Blower Boost Pressure (psi) |
RACE GAS Blower Boost Pressure (psi) |
|||||||||||
2 |
4 |
6 |
8 |
10 |
12 |
14 |
16 |
18 |
20 |
22 |
24 |
26 |
|
6.0 to 1 |
6.8:1 |
7.6:1 |
8.4:1 |
9.3:1 |
10.1:1 |
10.9:1 |
11.7:1 |
12.5:1 |
13.3:1 |
14.2:1 |
15.0:1 |
15.8:1 |
16.6:1 |
6.5 to 1 |
7.4:1 |
8.3:1 |
9.2:1 |
10.0:1 |
10.9:1 |
11.8:1 |
12.7:1 |
13.6:1 |
14.5:1 |
15.3:1 |
16.2:1 |
17.1:1 |
18.0:1 |
7.0 to 1 |
8.0:1 |
8.9:1 |
9.9:1 |
10.8:1 |
11.8:1 |
12.7:1 |
13.7:1 |
14.6:1 |
15.6:1 |
16.5:1 |
17.5:1 |
18.4:1 |
19.4:1 |
7.5 to 1 |
8.5:1 |
9.5:1 |
10.6:1 |
11.6:1 |
12.6:1 |
13.6:1 |
14.6:1 |
15.7:1 |
16.7:1 |
17.7:1 |
18.7:1 |
19.7:1 |
20.8:1 |
8.0 to 1 |
9.1:1 |
10.2:1 |
11.3:1 |
12.4:1 |
13.4:1 |
14.5:1 |
15.6:1 |
16.7:1 |
17.8:1 |
18.9:1 |
20.0:1 |
21.1:1 |
22.1:1 |
8.5 to 1 |
9.7:1 |
10.8:1 |
12.0:1 |
13.1:1 |
14.3:1 |
15.4:1 |
16.6:1 |
17.8:1 |
18.9:1 |
20.1:1 |
21.2:1 |
22.4:1 |
23.5:1 |
9.0 to 1 |
10.2:1 |
11.4:1 |
12.7:1 |
13.9:1 |
15.1:1 |
16.3:1 |
17.6:1 |
18.8:1 |
20.0:1 |
21.2:1 |
22.5:1 |
23.7:1 |
24.9:1 |
9.5 to 1 |
10.8:1 |
12.1:1 |
13.4:1 |
14.7:1 |
16.0:1 |
17.3:1 |
18.5:1 |
19.8:1 |
21.1:1 |
22.4:1 |
23.7:1 |
25.0:1 |
26.3:1 |
10.0 to 1 |
11.4:1 |
12.7:1 |
14.1:1 |
15.4:1 |
16.8:1 |
18.2:1 |
19.5:1 |
20.9:1 |
22.2:1 |
23.6:1 |
25.0:1 |
26.3:1 |
27.7:1 |
10.5 to 1 |
11.9:1 |
13.4:1 |
14.8:1 |
16.2:1 |
17.6:1 |
19.1:1 |
20.5:1 |
21.9:1 |
23.4:1 |
24.8:1 |
26.2:1 |
27.6:1 |
29.1:1 |
11.0 to 1 |
12.5:1 |
14.0:1 |
15.5:1 |
17.0:1 |
18.5:1 |
20.0:1 |
21.5:1 |
23.0:1 |
24.5:1 |
26.0:1 |
27.5:1 |
29.0:1 |
30.5:1 |
| Performance Automotive Warehouse Inc. 20235 Nordhoff Street, Chatsworth, California, 91311 USA Copyright © 1998-2008 Performance Automotive Wholesale Inc. All rights reserved. P.A.W. logos are trademarks of Performance Automotive Wholesale, Inc. Performance Automotive Wholesale recognizes all manufacturers' trademarks contained herein and disclaims any proprietary interest in their use. |