B Series Compression Ratio's for different setups

[allmotoronly]

Here's a list of different B series compression ratio's using oem honda pistons with different B series block/head combinations.

(All calculations use OEM Honda head gasket thickness.)



1) B16A Block with B16A/B, or B18C5 head

PR3 (USDM B16A) pistons: 10.20:1

PCT (JDM CTR) pistons: 10.80:1

P30 (JDM B16A) pistons: 10.40:1

2) B16A Block with B18C1 (P72) head

PR3 pistons: 10.44:1

P30 pistons: 10.65:1

PCT pistons: 11.07:1

P73-00 (JDM ITR) pistons: 10.42:1

P73-A0 (USDM ITR) Pistons: 9.94:1

P72-A0 (USDM GSR) pistons: 9.16:1

3) B18A/B Block with B16A/B, or B18C5 head

PR4 (B18A/B) pistons: 9.98:1

PR3 pistons: 11.32:1

P30 pistons: 11.54:1

PCT pistons: 11.97:1

P73-00 pistons: 11.31:1

P73-A0 pistons: 10.80:1

P72-A0 pistons: 9.99:1

4) B18A/B Block with B18C1 (P72) head

PR4 (B18A/B) pistons: 9.73:1

PR3 pistons: 11.59:1

P30 pistons: 11.81:1

PCT pistons: 12.27:1

P73-00 pistons: 11.57:1

P73-A0 pistons: 11.03:1

P72-A0 pistons: 10.18:1

5) B18C1/5 Block with B16A/B, or B18C5 head

PR3 pistons: 11.11:1

P30 pistons: 11.33:1

PCT pistons: 11.75:1

P73-00 pistons: 11.11:1

P73-A0 pistons: 10.60:1

P72-A0 pistons: 9.80:1

6) B18C1/5 Block with B18C1 (P72) head

PR3 pistons: 11.37:1

P30 pistons: 11.59:1

PCT pistons: 12.04:1

P73-00 pistons: 11.36:1

P73-A0 pistons: 10.84:1

P72-A0 pistons: 10.00:1

7) B20B/Z Block with B16A/B, or B18C5 head

P3F (B20B) pistons: 9.10:1

PHK (B20Z) pistons: 9.96:1

8) B20B/Z Block with B18C1 (P72) head

P3F (B20B) pistons: 9.24:1

PHK (B20Z) pistons: 10.14:1


If anyone needs any other B series combination thats not listed, pm me with the block, head, and piston type. I'll post different B17A specs if there is any interest. This stuff just takes a long time to figure up. I've been working on this for about 3 weeks in my spare time. I know this probably mostly applies to the N/A section, but I figured general tech would be the best place to put it so everyone could see.

Reps would be appreciated.