89 dx ti zc dohc ?'s
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88-89 Integra D16A1 used the same exact PM7/P29 piston as the 88-95 DOHC ZC with compression ratio of 9.6:1 - 86-87 Integra D16A1 used the PG6B piston with a smaller dome with compression ratio of 9.3:1
I ordered the P29s, (nippon) which my machine shop recomended. (had it bored over for perfect cyl. )
one interesting thing i noticed. is the nippon pistons have a 0 deck hight. so they sit flush with the deck. unlike factory. which has a -1, or -2 mm deck hight. i was told this should raise my C/R even more, which is a plus, just wounder why it says it is still 9.5-1.. but either way it will be fine, my head was milled .8mm for 10-1, If what the head guy at my machine shop (a friend of mine) said is true, i should have ruffly 10.5-1C/R(witht he deck hight change. anyone heared of this deck hight being diffrent? i have read some articles about it... but nothing solid...
so now that i have a good set of PM7s i am going to stick them in the D15 when it comes out...
one interesting thing i noticed. is the nippon pistons have a 0 deck hight. so they sit flush with the deck. unlike factory. which has a -1, or -2 mm deck hight. i was told this should raise my C/R even more, which is a plus, just wounder why it says it is still 9.5-1.. but either way it will be fine, my head was milled .8mm for 10-1, If what the head guy at my machine shop (a friend of mine) said is true, i should have ruffly 10.5-1C/R(witht he deck hight change. anyone heared of this deck hight being diffrent? i have read some articles about it... but nothing solid...
so now that i have a good set of PM7s i am going to stick them in the D15 when it comes out...
No idea about Nippon piston compression height. The OEM P29/PM7 is supposed to be .040" in the hole at TDC I think... which comes out to 1mm. If you raise the piston surface a whole millimeter, you'll raise the compression quite a bit. If the compression is listed to be the same, maybe the pistons have a lower dome and a higher crown- which would be better for more even combustion.
As far as static compression goes, you could realistically go to 12:1 or even 13:1 on a daily driver if you have the cams and the tuning to support it. When your static compression goes up, you need to go to larger cams (longer duration, more overlap) to bleed off some of your static compression. By doing that, you still reap the efficiency gains of the higher compression for more power plus you get the breathing benefits of the bigger cams. All this combined with really good tuning = great power.
FYI- I ran several engine builds at higher than 12:1 on pump gas in a daily driver. No problems for me, but I spent a LOT of time tuning the car. I also had access to 93 octane, but 92 didn't ping.
As far as static compression goes, you could realistically go to 12:1 or even 13:1 on a daily driver if you have the cams and the tuning to support it. When your static compression goes up, you need to go to larger cams (longer duration, more overlap) to bleed off some of your static compression. By doing that, you still reap the efficiency gains of the higher compression for more power plus you get the breathing benefits of the bigger cams. All this combined with really good tuning = great power.
FYI- I ran several engine builds at higher than 12:1 on pump gas in a daily driver. No problems for me, but I spent a LOT of time tuning the car. I also had access to 93 octane, but 92 didn't ping.
yeah thats what i was thinking, what stage cams should i run? i was thinking stage 2 bisimotos... or nippon's (but i have read some bad reviews) any sigestions?
would i need cams 4 sure? or use adjustable gears to advance/retard?
i have no problem waiting for the money to do it right, i just want to do it once.. lol
i was planing on runing factory compression and puting a SC on it, but i guess im going all motor lol.... no biggie, either will be fun for a DD.
also is there a way to figure out what lift/duration i need or would be optimal?
or is bigger the better?
lol
would i need cams 4 sure? or use adjustable gears to advance/retard?
i have no problem waiting for the money to do it right, i just want to do it once.. lol
i was planing on runing factory compression and puting a SC on it, but i guess im going all motor lol.... no biggie, either will be fun for a DD.
also is there a way to figure out what lift/duration i need or would be optimal?
or is bigger the better?
lol