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Discussion Starter #1
Firstly,

What would the compression ratio be with this combo? I used the comp calc from here.

http://www.c-speedracing.com/howto/compcalc/compcalc.php

By using D15B7 as basis with PM7/P29 pistons it came to about 10.7:1 CR

How will D15Z7 fare in this case? Will it work?

Secondly,

The D15Z7 during lean burn mode will have one intake valve closed. During that instance the air-fuel ratio will go as low as 20:1.

Will that be a potential problem for high compression setup?

So far I have not much luck finding much info on this so if anyone has some concrete info do share.
 

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Hmm, you should have it tuned, and maybe the tuner could add a bit more fuel during the period that only one intake valve is open to compensate.

Why not run a Z6 head?
 

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Discussion Starter #4
I'm sticking with the 3 stage head.

Fuel correction while using high comp setup at lean burn will definitely be done somewhere along line.

But what I am eager to know:
1. will it clear the valves (If I could clay it I wouldn't be asking)?
2. what will be the cr for using PM7/P29 pistons?
3. would it auto detonate during 20:1 af ratio (lean burn mode) whilst using PM7/P29?

One example I read is the JDM ES1 Civic. It is the same D15B block with 12v-16v VTEC-E lean burn mode but with 10.2 CR.
 

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the valve pockets of the p29's arent for vtec heads..
without claying? thats difficult , i wouldnt do it

for a d15 short rod motor (non d15B) the pistons is way below deck..
shaving will be needed to keep up any useful compression

any raise in compression is or should be matched together with a good tune..
thats why most switch to obd1 since its friendly with most tuning softwares,

any oem ecu wont be fast enough.. or atleast capable of switching the tune when ther are lean spots etc..
 

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Discussion Starter #6
If that's the case how's about overbore pistons?

The EPC states that there are two overbore option available for the stock P2J pistons being 13010-P2J-000 (stock), 13020-P2J-000 (0.25) & 13030-P2J-000 (0.50).

IMO there shouldn't be any valve clearance issues since there its still relatively same height. My guess could be a improvement of up to 0.2 CR for the largest overbore.

Looks like overbore seems to be the way to go. Other suggestions welcomed.

I'd like to downgrade to obd1 too but thus far there aren't alot of ppl know it well locally where I'm from. I'd still like to keep the lean burn function.

Which part of South East Asia you are from?
 

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philippines..

i can understand the not having people local, to do the obd1 conversion

this site has tons of info regarding that,
you could prolly look around for an obd1 complete uncut harness, have it shipped , get an obd1 box and do the rest.. but thats just a suggestion hehe
 

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Discussion Starter #8 (Edited)
I can get those locally here in Malaysia as we do have loads of EG civics running around.

Another alternative is probably downgrade from obd2b (yes mine is 99-00 model) to obd1, using the vtec-e ecu from the obd1 civic, chip it and use another rpm tach/vafc to engage the wild cam spool solenoid. That'll be sweet imo and probably easier to go through compared to the gsr/iab mode route.

too bad obd2 chipping is way harder than obd1 if not 3 stage vtec tuning would be alot of fun
 

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if its a 137mm rod motor.. not gona work...

as per transzex...

downgrading or not.. to obd1, its gona be the best option.. specially when u can get urself a p08 d15b ecu in ur area, which is chip friendly..
the tuning capabilities this can give you? will yeild more than ano other mod u can do to a vtec-e with a half baked tune...

just my 2cents
 

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Discussion Starter #12
Thanks for the insight guys really appreciate it.

looks like overbore would be the easiest route hence maintaining the rod/stroke ratio but still bump the cr up a notch.

How about the piston from the JDM ES1 civics? its a lean burn D15B also but with 10.2 CR. So far the EPC I have does not have the part number for it. Anyone who has more info on it kindly let me know as I wish to confirm whether its compatible with the 3 stager.

The info on the ES1 Civic with the iE trim for the lean burn is found here pre-translated

http://64.233.179.104/translate_c?hl=en&u=http://www.honda.co.jp/factbook/auto/CIVIC/200009/029.html&prev=/search?q=honda+factbook+civic&hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&hs=MV9
 

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Discussion Starter #13 (Edited)
Hi guys,

It's me again. I read that there is a possible combo for d15b vtec with 01-05 gx (PMS) pistons. So far my googling hasn't told me it works concretely.

I've asked a local forumer named Dog and waiting for his reply:
http://www.d-series.org/forums/showthread.php?t=14618&page=13

Has anyone got any solid information whether it works or not and some improvement numbers (crank hp, mileage, drivability etc)

All insights are welcome.
 

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That combo will work, increasing cr to 11.3

Hard part is to find those pistons.

Tuning will be needed for sure!
 

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That combo will work, increasing cr to 11.3

Hard part is to find those pistons.

Tuning will be needed for sure!
How do you know the displacement of his 3 stage VTEC head? I have not seen that info posted anywhere.

How are the pistons hard to get? I found them in minutes from Majestic Honda.

OP, you need this calculator: http://www.zealautowerks.com/dseries.html

P72/IAB is the only way I would modify/tune a 3 stage VTEC. I would not trust other methods.
 

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Discussion Starter #16
That combo will work, increasing cr to 11.3

Hard part is to find those pistons.

Tuning will be needed for sure!
Yeah How did you get that number? 11.3 CR

I read on the Z1 head would get 10.8 CR

Looking at the stock specs Z7 would have 9.6 CR whilst Z1 would be 9.3 CR so it could be possible.

I read somewhere the pms could be within the $35-50 range.
 

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As far as i know/read, the d15z7 is pretty the same as the d15z6 (p2j cast, p08 pistons, 137mm rods). If you throw a pms piston, cr should be 11.3 using zeal calc.

About PMS, i couldn't find it at my country, and some places won't take international orders (don't know about majestic) i may have said that in my first post...
 

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Discussion Starter #18
After some googling, I found out another nice donor to bump up the compression.

The engine code is D15Y4 vtec-e found in ES Civics (2001-2005) with 10.2 CR.

Similarly two other D15 variants for the ES Civics are the D15Y3 non vtec with 9.3 CR and D15Y5 normal vtec with 9.9 CR

Now the question is what is the piston code for D15Y4?
 
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