good pistons to start all motor package or no?

 

yes there good !specially for 91 octane (which is all that we have here in cali )
but also depends on the type of cams that you are planning to run .
like the skunk stage 3 lift 12.8 they recommend forge JE do to the deep valve pockets ,such high lifts

 

If you will be going through the expense of installing new pistons, you probably want to go with ones that will yield a higher comp. ratio. If not, you could look into a thinner headgasket and maybe some milling if you are planning on sending the head out.

 

I would go with JDM P30 Pistons instead.

 

what will my comp rtio be with p30 b16 pistons? SGT why p30's?

 

JDM ITR will give about 11.3:1
JDM P30 will give about 11.8:1
USDM P30 will give about 11.6:1

It all depends on what cam you are gonna use.
If you want ITR pistons, save some money and get USDM ones.

 

How about CTRs? Thats like what, 12.2:1 in a B18C1? Should be OK with 91 octane and some decent tuning.

 

right

 

SGT, why do the P30's yeild such a high compression ratio? Im looking on running TODA A's...would that be a good set up with those pistons? Here in SC we have 92-93 octane. I wouldnt run into any clearance or other problems running those would i?

TIA...

 

no prob's at all with that setup.. p30's yield a higher cr due to the taller dome (they displace more volume).. check out my calculator for more oem combinations

 

Sorry for the newbie question.....why would it matter what cams to use?? I thought higher compression will yield higher HP?

 

spec A cams would be good with mid-11 compression ratio

Larger cams with more overlap effectively reduce dynamic compression ratio.
So to make up for that you have to increase the static compression ratio to
compensate.

 

There is no USDM P30 that I am aware of. USDM PR3 pistons (out of a Civic Si) will only net an 11.3 cr...just a tad bit higher than that of the JDM R pistons.

 

94+ b16's from the usdm del sol vtec's come with p30's.. these are identical to the pr3's that everyone is so familiar with..

 

hmm..did not know that, but wouldn't they yield the same cr as the Civic Si pistons? Or more as he stated?

 

civic si = p30

PR3 was the old 1g b16a. after 92 the b16a code changed to p30 due to some
updated parts. The JDM compression ratio is 10.4 in b16a from 1992+ while
the older PR3 and USDM P30 are still 10.2.

The compression is more in a 1.8L due to the increase in stroke, the same reason
why a 10.8:1 civic R piston will yield 12:1 or more in a 1.8.

The main reason why the numbers are higher, are due to the B18C head rather
than the B16A/R head

 

actually, the civic si does have PR3 pistons.

 

part # i recieved said P30.
But they probably have PR3 stamped on them.
Same part. But my point was that you cant go to the dealer and get PR3 pistons.

 

sgT, would it be ok to use the P30 in a B18C5 with high lift cams like Toda B or Jun III?

 

i would get CTR pistons for those cams.
P30 = not enough compression

 

that would only give you an 11.3 cr. Get some ***** and go CTR

 

Or get some quality and go forged

 

Since when does a piston need to be forged to be of good quality???

Sometimes i like a quiet motor.

 

Thats for the info sgT.