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