Difference Between B18c1 And B18c5

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Senior Member
B18C5 <> B18C1

Displasment: 1797 <> 1797

Power: 195@8000 <> 170@7600

Torque: 130@7500 <> 128@6200

Compression: 10:2:1 <> 10:0:1

Bore: 81 <> 81

Stroke: 87.2 <> 87.2

Cam Design: Dohc <> Dohc

Vtech: Yes <> Yes

OBD: 2 <> 1 or 2

Well the differece is only Commpression Ratio so that means if I will put new Dome Pistons in B18C1 then its going to have the same amount of horse power as B18C5?
Cuz I want to put it in my Civic and I need OBD1 not OBD2 as in B18C5.
So if anybody know or did something like that or know whats going to happed if I will do it please tell me.
Thank you.

Ow yea I got all the information from www.hondaswap.com<preferences<engines


Super Moderator
there are a few diffrent reasons why the ITR is more powerful and is also more expensive. Reason why it is more powerful are higher compression pistons, more agressive valve train (stiffer spings, bigger cams lobes) and also there was a slight port and polish job that was done at the factory. Also, the intake manifold is a better design and same with the header. Also, the ITR's had lighter flywheels.

Reason why it cost more is also because of its tranny. The tranny has a LSD in it, and has much shorter gearing.


Senior Member


Senior Member
So anyway how much power do you think I will get with DOME pistons in B18C5?


usdm itr pistons in a gsr will bump your compression to 10.836:1
jdm itr pistons in a gsr will bump your compression to 11.362:1

the reason why putting itr pistons into a gsr doesn't yeild it compression is because of the GSR's head. the cumbustion chamber's are different as well.
gsr cc = 41.60 per cyl. while the itr and b16 cc's are 42.70 per cyl.

so, basically, you have a SMALLER area that you are pushing up upon with your piston. as you know, more of somthing in a smaller space equals more psi, etc, or in our case, compression.

like i said, its much different. you are looking for a poor mans ITR swap, really.
if that is the case, what i suggest you do is to get :
gsr block
gsr rods
ctr pistons (im pretty sure the ctr pistson fit the gsr rods... but don't quote me)
b16a3 or b16 sir2 obd1 head
port it
valve train it out with skunk2 stuff or oem honda itr/ctr parts and cams
skunk2 intake manifold
jdm 4-1 itr header with the collector

as you can see, the poor mans ITR actually costs MORE than a regular ITR does - but it does make for an easier swap.
However, dropping an ITR into a 5th gen is not that hard. we just finished one a couple weeks ago.