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.

[integra82786]

good stuff, I was just trying to calculate my ratios before and after the build. thanks for the info...

[WHT_EP3]

sooooo what would be the best N/A set up

[TheChosenOne]

Very nice! I have been waiting for this. Quite honestly, some other people's numbers on IA are a little off...

P72 head/B18A/B Block

STD = 13.170743903246784

--compared to--

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

I know some people who have run this setup on pomp gas for years, and 13.17:1 just isn't possible with 93. 12.27:1 sounds MUCH more accurate.

[TheChosenOne]

sooooo what would be the best N/A set up

Brian... you know better...lol.

The answer for this question is multiple things. When you say best, are you talking about the most Hp, or the most Torque, or the most reliability??? Knowing you, your probably talking about the most power in general.

For the sake of argument, I am throwing out reliability just this once.

As far as B-series are concerned with stock pistons, the best N/A motor would have to be: Ls Block w/ CTR pistons, and a GSR head. Hands down. The Ls/Vtec offers more torque, and more Hp than a full gsr with CTR pistons. (keep in mind this answer is given without taking reliability into consideration).

Honerable mention goes to the B20Z with the GSR head. Don't sleep on the 2.0vtec monster. If this question wasn't "stock piston specific", the B20 with anything above 11:1 compression and a crank balance would rape any 1.8 liter.

[WHT_EP3]

B20z exactly

[VickNotic]

good thread.. i was about to search for my build setup .. and i thought i saw a thread in here.. and thur it is.. thanx..

and j/w why is there not a Dseries compression test in here also..? can we get one .. also..

[allmotoronly]

good thread.. i was about to search for my build setup .. and i thought i saw a thread in here.. and thur it is.. thanx..

and j/w why is there not a Dseries compression test in here also..? can we get one .. also..

I may eventually do one, but I will not have time to do it anytime soon. The B series chart took me days to do.

[suprapower]

been working on my b18 for a while. very helpful. thanks

[xbn83]

http://www.c-speedracing.com/howto/c...c/compcalc.php
Much easier to use than reading so much.

[jerseyef9]

b20z wit ctr pistons and wit a gsr or b16a head

[Just_CHill]

So lets say I was buying some aftermarket B16 pistons for an LS/VTEC, and I wanted to get around 11.5. Would I go for the 10.75:1 B16 pistons?

[southside]

b20z wit ctr pistons and wit a gsr or b16a head

you cant use ctr pistons in a b20 81mm pistons and 84mm block equals fail!

[allmotoronly]

you cant use ctr pistons in a b20 81mm pistons and 84mm block equals fail!

man just wrap the piston with duct tape until it fits better lolol. Didn't you know?

[southside]

man just wrap the piston with duct tape until it fits better lolol. Didn't you know?

Yea that dude needs motor setups for dummies book

[Tensa_Zanget]

GREAT WRITE UP MAN!

[Tech5]

Good post

[allmotoronly]

thanks!

[REDEVO777]

duct tape lol

[scubaspeed]

Glad someone finally posted this! THANKS!

[VickNotic]

how about a LS crank on ITR block p73-00 gsr head? 3 layer HG ?? can this be done?

[envision]

Good Stuff here

Just email link to 3 friends who were arguing with me about this the other day

[sleeper1979]

I hope you people whos giving advice are mechanic because anyone can talk but dont know what it really mean but to me I would say b18c itr bored out 2.0 buddy

[SLow_POke]

IA gets stranger byt he day,


and yhes u can mate the itr and gsr blocks with the ls crank... 89mm crank just after market rods .


if u have all the specs you can do the math to com up with these numbners.

[SLow_POke]

btw i know nothing abuot cars

[Whiteboy572]

Neither does sleeper1979...