High comp Mini me :)

N/A build discussion
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By Greasedmonkey
- Mon Jul 20, 2009 4:35 pm #131696 I dont see how your are getting more CR out of the PM3s. They always come up less for me. With his set up Im getting 12.76:1 CR. PM3 give it a 12.42:1

really high compression for a D motor non the less. There is no real need to go that high on a street motor. 11.5:1 is really the highest I would go now. You can make the power on less CR and its easier for the tuner to do so.
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By Mr. Pink
- Mon Jul 20, 2009 5:29 pm #131715 the civic is not my only car. i have my truck as well, but i understand what your saying, i may not go to 12.5:1 i may only go 12:1, or 11.5:1
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By d-mon
- Mon Jul 20, 2009 11:01 pm #131896
Greasedmonkey wrote:I dont see how your are getting more CR out of the PM3s. They always come up less for me. With his set up Im getting 12.76:1 CR. PM3 give it a 12.42:1

really high compression for a D motor non the less. There is no real need to go that high on a street motor. 11.5:1 is really the highest I would go now. You can make the power on less CR and its easier for the tuner to do so.

i posted a link to the compression calculator i used.
pm3's are the tallest honda d-series pistons
compression height for pm3 =30.7mm
compression height for p29 = 29.0mm
pm3s are too tall too put in a d16, they stick out of the block with 137mm rods. only fit in d15 with 134mm rod.
you are correct that 12.xx:1 is very high compression for a street driven d-series, and will sacrifice drivability. (poor idle, no power below ~4k, etc)
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By Greasedmonkey
- Tue Jul 21, 2009 12:36 am #131921 I used the same calc you linked, and I always use that one.

D15 bottom end with z6 head didnt show the PM3 to have a higher CR. Compression hieght is more, but it still has a -1.5cc dish. P29s have a 7.2 cc dome, with a comp hieght not that far off.

In fact, I just checked again and with the D15 block, crank and rods the PM3 seems to stick out of the deck. By .059 inches. That wont work at all.
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By Mr. Pink
- Tue Jul 21, 2009 1:08 am #131925 GreasedMonkey,

thats exactly why i am sticking with the P29's because they dont stick out of the deck and i wont have to worry about a valve hitting them like i would with the PM3's
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By d-mon
- Tue Jul 21, 2009 5:31 am #131965
Greasedmonkey wrote:I used the same calc you linked, and I always use that one.

D15 bottom end with z6 head didnt show the PM3 to have a higher CR. Compression hieght is more, but it still has a -1.5cc dish. P29s have a 7.2 cc dome, with a comp hieght not that far off.

In fact, I just checked again and with the D15 block, crank and rods the PM3 seems to stick out of the deck. By .059 inches. That wont work at all.

yeah, when i got home i tried the compression again. this time it was:
p29 12.46:1
pm3 12.06:1

but there is still the valve relief issue.
once you mill the head this is a serious consideration.
especially with a performance cam.
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By Mr. Pink
- Tue Jul 21, 2009 3:26 pm #132035 the valve relief is an issue regardless of piston choice, unless i go with a p28, but i would get nowhere near the numbers that i want.
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By BLaCkSiLo
- Thu Sep 10, 2009 2:03 pm #142794
Mr. Pink wrote:i will be at 12.5:1 give or take.

I have an auto, ARP does not make the bolts for the flexplate. and before you say something about 5 speed swaping, my car is an auto for health reasons(arthritis and a replaced knee)

I am also not worried about the Main's as i wont be making over 200whp. and i will be having Kinsler fuel injection make the ITB's for me(eventually). but for know the Blox manifold and S2 tb.


can you tune an auto well? i was under the impression that you couldn't tune/chip/socket an auto ecu in obd1 honda?

or do i have bad info? .... you said you boosted 14psi on an auto integra?
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