ek9 pistons in a b18c5


RagingAngel said:
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
Click to expand...

i am just speaking from experience. there is not need for that kind of compression on a street car its over kill. u can make 200whp fairly easy on a stock jdm itr bottom. most people don't have money to build a bottom end and buy cams ,etc all in one shot. i ran ctr pistons in a b18c5 with ctr cams and it wasnt impressive at all. all in all i would stay stay away from pct slugs, there good for the price but theres alot better out there for that compression range.
 
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turbociv910 said:
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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so have i but u can make the same power with less compression. why put more strain on your bottom end if u dont have to? big compression motors need to be re ringed alot earlier than something less conservative.
 
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...

RagingAngel said:
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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so do the p30 give more compression than the itr pistons.


what rods should i use if i go to use the p30's. i heard the itr ones are to wide.
 
RagingAngel said:
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
Click to expand...
your almost spliting hairs here. with oem gasket jdm itr's 11.32, p30s 11.27.
same ****
ZealAutowerks - Honda B-Series Compression Calculator
 
crazy eyes said:
so do the p30 give more compression than the itr pistons.
pretty much same thing, itr's .05 higher.


what rods should i use if i go to use the p30's. i heard the itr ones are to wide.
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i know for a fact that p30's fit onto ls rods and if memory serves me correct i think 1mm needed to be shaved off each side of my pct's to fit my itr rods but my memory is shot and i might be mistaken.if thats the case then the same needs to be done for the p30's. that can be done for $50 the most at a machine shop which you''l have to go to anyway to press the wrist pins.
 
whether or not I'm splitting hairs is still fact.

The other point being is that JDM ITR pistons are a superior piston as they have wrist pin cooling holes and molybdenum coated skirts.

Along with a flatter dome - you get more compression with better quality compression too this way....the main crux of using PCT pistons due to their extreme dome.
 
The ITR pistons have higher compression than the P30's. Didn't know about that oiling factor though RA, good info.

Also worth noting is what RA said about the piston coating, i pulled my pistons out when they had about 60,000miles on them of hard driving and the coating was still intact!!
 
well can anybody recommend me a piston oem or aftermarket that will boost my compression but still run safely on 95
 
blinx9900 said:
The ITR pistons have higher compression than the P30's. Didn't know about that oiling factor though RA, good info.

Also worth noting is what RA said about the piston coating, i pulled my pistons out when they had about 60,000miles on them of hard driving and the coating was still intact!!
Click to expand...

For most, this is a great upgrade or a piston that will be "easy" to install if you do not trust or know the quality of work from your machine shop.

some pictures for reference:

molybdenum skirts:
rparts3.jpg


wrist pin cooling holes:
rparts2.jpg


Be wary of aftermarket cast pistons which do not have these features; the latter being easy to add with a steady hand and drill press.
 
sek2dts@aol.com said:
The Old One - Energy Dynamics : Components : Forged Pistons

CP Pistons - Home

JEPistons.com | JE Pistons Sport Compact

Honda JDM P73 Integra Type-R Piston Set (STD/OS) - JHPUSA
Click to expand...

Things like piston to wall clearance should always be taken into account and this is especially crucial for forged pistons. This is essential to minimize piston slap and overall wear. Cross hatch/honing is also to be verified. All these specs are to be followed from the piston manufacturer, along with ring gap.

Many have also suggested deleting the oil squirters with a forged piston as they handle the heat much better. That should be up to you, your mechanic and your particular application.

Delete kits are available from Golden Eagle etc.

The benefits of deleting the squirters are:
- a lighter piston (there's no constant supply of oil being sprayed on the underside during reciprocation)
- higher overall oil pressure

we decided against deleting a motor we rebuilt with mahle forged pistons based on two main points:
- we used the stock rods and didn't feel like modifying the small end of the rod for more wrist pin cooling
- the car is used mainly for lapping/track days and we felt the additional cooling would be beneficial.

Choose wisely :)
 
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