Dynamic Compression Ratio Calculator for LS V8 Engines
(For a dish, positive; for a dome, negative)
Oztrack LS Camshafts – Dynamic Compression Ratio Calculator Data
Based on Static Compression Ratio of 10.7:1 in 6L & 6.2L
FE 8.09
DR 8.10
HP1 8.16
HP3 7.96
HP9 7.98
HPS 7.73
HPX-R 7.87
HP7-R 7.30
The following table provides detailed guidelines for setting the maximum dynamic compression ratio (DCR) based on the fuel type. The table compares premium 98 RON fuel (common in Australia) with E85 ethanol-based fuel. Because effective octane ratings differ and E85 offers a higher knock resistance despite lower energy content, engines tuned for each fuel may require different maximum DCR limits.
| Fuel Type | Effective Octane Rating (RON) | Recommended Maximum DCR | Notes/Considerations |
|---|---|---|---|
| Premium 98 Fuel | 98 RON | Ideal is 8.00:1 – 8.25:1 | Suitable for high-performance engines tuned for premium fuel. Requires precise tuning to avoid knock. |
| E85 Fuel | Approximately 105–110 RON* | 8.25:1 – 9.40:1 | Higher effective octane allows for a higher compression ratio. |
