Honda Acura B Series Piston Tech Guide
Compression Ratio for Stock Engines
| Engine-Piston | B16A-PR3 | B16A-P30 (JDM) | B17A1-P61 | B18C1 P72-A0 (US) | B18C1 P72-00 (JDM) | B18C5-P73-A0 (US) | B18C5-P73-00 (JDM) | B16B-PCT (JDM) | B18B |
| Compression Ratio | 10.2 | 10.4 | 9.7 | 10.0 | 10.6 | 10.6 | 11.1 | 10.8 | NA |
Approximate Compression Ratio for Engine-Piston Mixes
| Engine | Piston | ||
| B16B or Civic Type-R | P73 (US) Integra Type-R | P73 (Japan Spec) Integra Type-R | |
| B16A | 11.1 | 10.4 | 10.7 |
| B17A | 11.4 | 10.6 | 10.8 |
| B18C w/GSR Head | 11.8 | 10.9 | 11.4 |
| B18C w/Type-R or B16 Head | 11.6 | 10.6 | 11.1 |
Approximate Piston Measurements
| Engine-Piston | B16A-PR3 | B16B-PCTX | B17-P61 | B18B-PR4 | B18C-P72 | B18C5-P73 | B20B | H22A1 |
| Rod Length | 5.290 | NA | 5.208 | 5.394 | 5.429 | 5.429 | NA | 5.63 |
| Stroke | 3.031 | NA | 3.205 | 3.504 | 3.433 | 3.433 | NA | 3.571 |
| Bore Size | 3.189 (81mm) | 3.189 (81mm) | 3.189 (81mm) | 3.189 (81mm) | 3.189 (81mm) | 3.189 (81mm) | 3.307 (84mm) | 3.425 |
| Head C.C. | 42.7 | 42.7 | 42.7 | 45 | 41.6 | 42.7 | 53.8 | |
| Compression Height | 1.180″ | 1.210″ | NA | 1.180″ | 1.183″ | 1.190″ | 1.165″ | NA |
| Dome Height | .098″ | .253″ | NA | -.055″ | .000″ | .070″ | -.035″ | NA |
| Weight | 299g | 327g | NA | 280g | 305g | 310g | 312g | NA |