ek9 pistons in a b18c5


C

crazy eyes

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Oct 10, 2007
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i have a b18c5 here and the piston rings need to be done on it. so i was thinking of changing to ctr pistons while the block is split.


i'm just wondering would this be to much compressuion on 95 octaine.also will it need a re map after changing the pistons


i'm think of using a spoon or/mugen thin head gasket to would u reck this would be too much.


thanks
 
I think you will need to run 98 octane because of the high compression (somewhere around 12.8 right?) and a remap is neede for sure but compression that high seems ideal to me for big cams :D
 
_JT said:
I think you will need to run 98 octane because of the high compression (somewhere around 12.8 right?) and a remap is neede for sure but compression that high seems ideal to me for big cams :D
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we havn't got 98 over here thats the problem. if i have to get it mapped i was thinkin of gettin it mapped for e5 which is 97 afaik. but i'm not sure if it will be even safe on that



do u reckon the compression would be that high with pistons alone
 
You will have 12.7:1 compression with the OEM head gasket, that is achievable with 95 Octane but good tuning will be paramount!!

Ek9 Pistons and a spoon/mugen head gasket will bring you up to 13:1

Honestly i suggest you use the JDM ITR pistons and a mugen/spoon head gasket, that will land you around 11.5:1 which is perfect for a street car on pump gas. No matter what you do if you alter compression you NEED to have your car tuned properly.
 
blinx9900 said:
You will have 12.7:1 compression with the OEM head gasket, that is achievable with 95 Octane but good tuning will be paramount!!

Ek9 Pistons and a spoon/mugen head gasket will bring you up to 13:1

Honestly i suggest you use the JDM ITR pistons and a mugen/spoon head gasket, that will land you around 11.5:1 which is perfect for a street car on pump gas. No matter what you do if you alter compression you NEED to have your car tuned properly.
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do u think the ctr pistons would be to much even if it was mapped for e5.

i tink the 13.0 compression would be way to high on the street so i'll be keepin my oem headgasket if i was doin it
 
crazy eyes said:
do u think the ctr pistons would be to much even if it was mapped for e5.

i tink the 13.0 compression would be way to high on the street so i'll be keepin my oem headgasket if i was doin it
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any special reason your going with ctr's? theres more con's than pros when using pct pistions in a 87 stoke setup. for 1 there heavier than jdm and usdm itr pistons. 2 what cams are u running? larger compression and larger cams run hand and hand. so if your gonna run a oem cam i dont think its to good of an idea as 2 much compression can restrict how high your motor revs out and detonation is always gonna be a factor on pump gas no matter what anyone says. i would def go jdm itr or p30 pistons with a spoon gasket or use flat top valves.
i ran a b18c5 setup in a eg with ctr pistons with ctr cams, skunk2 stage2's, and toda b's. on the dyno with the ctr cams we needed to play with the cam gears alot and bleed some of the compression out cause it was having a hard time making power up high. stage 2 and b's were a whole different story.
 
sek2dts@aol.com said:
any special reason your going with ctr's? theres more con's than pros when using pct pistions in a 87 stoke setup. for 1 there heavier than jdm and usdm itr pistons. 2 what cams are u running? larger compression and larger cams run hand and hand. so if your gonna run a oem cam i dont think its to good of an idea as 2 much compression can restrict how high your motor revs out and detonation is always gonna be a factor on pump gas no matter what anyone says. i would def go jdm itr or p30 pistons with a spoon gasket or use flat top valves.
i ran a b18c5 setup in a eg with ctr pistons with ctr cams, skunk2 stage2's, and toda b's. on the dyno with the ctr cams we needed to play with the cam gears alot and bleed some of the compression out cause it was having a hard time making power up high. stage 2 and b's were a whole different story.
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what are p30 pistons?


im goin for the ctr pistons because i dont want after market pistons and i'd like somthing with a bit more compression than itr pistons. any recommendations.


i'm still usin itr cams but i'm planning on up grading the cams eventually i'm just doin the pistons first as the rings need to be done.
 
crazy eyes said:
what are p30 pistons?


im goin for the ctr pistons because i dont want after market pistons and i'd like somthing with a bit more compression than itr pistons. any recommendations.


i'm still usin itr cams but i'm planning on up grading the cams eventually i'm just doin the pistons first as the rings need to be done.
Click to expand...

Google is ur friend.
 
crazy eyes said:
what are p30 pistons?


im goin for the ctr pistons because i dont want after market pistons and i'd like somthing with a bit more compression than itr pistons. any recommendations.


i'm still usin itr cams but i'm planning on up grading the cams eventually i'm just doin the pistons first as the rings need to be done.
Click to expand...

trust me dont use ctr pistons its overkill for what your doing, use p30(jdm b16 pistons) pistons with a spoon gasket thats about 11.6.1 comp. u def do not need over 12.1 compression for a street car. there's also nothing wrong with using after market pistons as they are way better being forged which adds way more strength and reduces weight in some cases. if your stuck on the ctr psitons i would start thinking about researching and buying all the other stuff thats gonna accommodate that compression( injectors, management not a vafc or something similar, cams, springs, cam gears, and def a good header and exhaust setup) as over 12.1 compression on stock cams and stock ecu will not work to good.
 
sek2dts@aol.com said:
trust me dont use ctr pistons its overkill for what your doing, use p30(jdm b16 pistons) pistons with a spoon gasket thats about 11.6.1 comp. u def do not need over 12.1 compression for a street car. there's also nothing wrong with using after market pistons as they are way better being forged which adds way more strength and reduces weight in some cases. if your stuck on the ctr psitons i would start thinking about researching and buying all the other stuff thats gonna accommodate that compression( injectors, management not a vafc or something similar, cams, springs, cam gears, and def a good header and exhaust setup) as over 12.1 compression on stock cams and stock ecu will not work to good.
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Agreed, jdm b16 pistons or jdm itr pistons get my vote.
 
sek2dts@aol.com said:
trust me dont use ctr pistons its overkill for what your doing, use p30(jdm b16 pistons) pistons with a spoon gasket thats about 11.6.1 comp. u def do not need over 12.1 compression for a street car. there's also nothing wrong with using after market pistons as they are way better being forged which adds way more strength and reduces weight in some cases. if your stuck on the ctr psitons i would start thinking about researching and buying all the other stuff thats gonna accommodate that compression( injectors, management not a vafc or something similar, cams, springs, cam gears, and def a good header and exhaust setup) as over 12.1 compression on stock cams and stock ecu will not work to good.
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Bit offtopic, but my mid-term planning involves using a b18c4 bottom with CTR pistons and then adding BIG cams with springs, valves etc. Of course after having modified the intake etc and getting Hondata management or something like that. What do you think of that?
 
mEh

P30 pistons yield a lower compression value than JDM ITR pistons. Don't trust what you see on compression calculators that do not know how to take the compression height into account.

In terms of DOME, it goes from

highest: PCT,
- P30,
- PR3
- JDM ITR
- US ITR

but in actual **compression** for the B18C it is:

Highest: PCT
- JDM ITR
- P30
- PR3
- US ITR
 
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_JT said:
Bit offtopic, but my mid-term planning involves using a b18c4 bottom with CTR pistons and then adding BIG cams with springs, valves etc. Of course after having modified the intake etc and getting Hondata management or something like that. What do you think of that?
Click to expand...

I think you should start your own topic and specify just how big of a cam you intend to use and what other supporting modifications you have/will be using.
 
_JT said:
Bit offtopic, but my mid-term planning involves using a b18c4 bottom with CTR pistons and then adding BIG cams with springs, valves etc. Of course after having modified the intake etc and getting Hondata management or something like that. What do you think of that?
Click to expand...

what kind of power goal u have in mind? u more of a drag race guy or an auto cross guy?
 
RagingAngel said:
I think you should start your own topic and specify just how big of a cam you intend to use and what other supporting modifications you have/will be using.
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Alright, will do so when I come to that bridge....might be a while :p
sek2dts@aol.com said:
what kind of power goal u have in mind? u more of a drag race guy or an auto cross guy?
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More track minded. Need to be able to drive it normally on the road, but no big priority...but if anyone objects, don't wanna hijack the topic :p
 
sek2dts@aol.com said:
trust me dont use ctr pistons its overkill for what your doing, use p30(jdm b16 pistons) pistons with a spoon gasket thats about 11.6.1 comp. u def do not need over 12.1 compression for a street car. there's also nothing wrong with using after market pistons as they are way better being forged which adds way more strength and reduces weight in some cases. if your stuck on the ctr psitons i would start thinking about researching and buying all the other stuff thats gonna accommodate that compression( injectors, management not a vafc or something similar, cams, springs, cam gears, and def a good header and exhaust setup) as over 12.1 compression on stock cams and stock ecu will not work to good.
Click to expand...

If he is planning on using some relatively large cams say JUNIII or whatever down the road, the compression is fine. Static compression ratio has everybody running scared but with big enough cams, it will lead to a more favorable dynamic compression ratio.

This is one of the key elements as to why big cams do not work well with low/stock compression, it makes your already mild compression lose even more "pump!"

Any time one goes digging into the internals of the motor in efforts to bump the compression ratio either via headgasket and/or pistons, ECU remapping and the consideration of going to larger injectors is a must.

Even a completely bone stock ITR can benefit from better ECU tuning as seen here:
Hondata - 97 type R
 
Hmmm....that thing about the cams and static and dynamic compression confirmed what I was thinking :D
 
ive tuned setups with the ek9 pistons in a 1.8 block with 12.7 compression on 93 octane gas multiple times. No problems with detonation.
 
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