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Discussion Starter #1
nOOb here

ok so I have a obd2 jdm d15b 3 stage that I want to build. I've been researching and there seems to be some confusion on this engine. I wanted to know if i can use y8 pistons and rods or do i need to get custom length rods. as for the head they say there isn't any cams for the head. I would like your inputs.

My plans
Head (p2j-a?4?)(cant tell if it says A or 4)
Supertech Valve/Springs/Retainers (y8 or zc?)
Bisimoto 2.4 level cam(y8 or zc?)
Arp head studs(not sure if i need y8 or z6)
Skunk2 pro series manifold(got it)
Y8 throttle body(got it)
Golden eagle fuel rail
RC 550cc injectors
Block (jdm d15B)
Vitara YCP pistions
Eagle H beams rods(custom or y8 length?)
Tranny (y8)
MFactory lsd
4 stage Competition Clutch
Completion Lightweight Flywheel
Engine Management
P28 with s300(got it)
Turbo
Precision 5431 t3t4
(have a ebay turbo for now)
Fuel Pump
Walbro 255(got it)
 

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ej8
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As the man said.
The jdm motor tend to have a lil bit more power but that's because of higher compression.
And when swapping one in for a replacement there great.
Bit when building one it's different story. Parts are different and it's can be hard to find out which part is needed.
 

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93 DelSol S, 95 DelSol Si, 01 Odyssey EX, 04 CRV EX
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the jdm d15b takes 0.1 liters away by putting the wrist pin higher on the piston, thus lowering deck height.

this is your concern.

to verify your crank fits this description, your main and rod journals will have the same measurements give or take a few thousandths.

from there, build and check clearances along the way.
 

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93 DelSol S, 95 DelSol Si, 01 Odyssey EX, 04 CRV EX
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no replacement for displacement. the 1.6 has more potential and larger main bearings which is good. also the D16 has a longer stroke.
displacement isnt always key. r/s ratio, as well as b/s ratio are key to power potential. the reason a dohc with a different bore and stroke makes waaaay more power. i dont need to go in-depth, but suffice to say, dynamic compression trumps all. (ramjet/pulsejet anyone?)

why is it the jdm d15 being soo close spec wise makes as much power as a z6? location from crank, less time in the quenching space of rotation, more harmonically balanced, less rotating mass, etc.
 

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Discussion Starter #8
One of my concerns was the deck height. But as I researched ppl have said due to the crack in the d15 it should be fine. I just want more opinions. I could also use a thicker gasket?
 

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Compression, 1.6l at 9:1 c/r vs 1.5l at 9.3:1 c/r. A b16 has higher compression vs a d16 and a very different r/s ratio. The d15b vs d16 isnt much difference. Im just trying to tell you the benefits do not outweigh the headache. If you have the block already go for it and build it but the head you cant do much but leave it stock


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Discussion Starter #10 (Edited)
Do u think I would run into a deck height problem with my rod choice. Or do I need custom length rods. As for the head I'm not to concern if I get to make 280 whp ill be fine if I don't Ill just swap my y8 head into it. Also I could that bisimoto makes cams for the d15b can anyone confirm if they work for the p2j d15b head or just the po8 head
 

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have you searched for the difference between the obd1 D15B vtec and the OBD2 D15B Vtec?

OBD1 is basically a 1.5L with a custom crank, D16 rods, D16z6 head and a custom cam offset 4.75 deg. sometimes the cam is slightly more aggressive. so yes you can run any D16Z6 cam in it with the correct cam gear or adjustable.

OBD2 has 3-stage vtec that's why there are no cams for it. you will have to figure out how to activate the second/third stage vtec spool solenoid and that is where the headache comes from. it can be done but how far do you want to get into it?

do some research. the 3-stage is just an economy thing if i were you and wanted to run that engine i would simply drop a y8 head on it and call it a day. then you only have to worry about mechanical timing. most people give up on the 3-stage vtec d15b that's why there is not much info on it. your best bet is to get a hondata s300 and connect the extra spool valve to IAB since it's an RPM activated switch. for that you will need a conversion harness and a relay.
 

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I built a jdm d15b vtec bottom end with vitara pistons and FJ d16 custom length rods. I used a z6 head and a stock z6 headgasket. The pistons did sit above the deck height but the engine ran and took it into vtec without the pistons hitting the head. It yeiled around 9.4:1 compression and had great throtle response.

You will have no problem using eagle rods.
 

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Discussion Starter #13 (Edited)
have you searched for the difference between the obd1 D15B vtec and the OBD2 D15B Vtec?

OBD1 is basically a 1.5L with a custom crank, D16 rods, D16z6 head and a custom cam offset 4.75 deg. sometimes the cam is slightly more aggressive. so yes you can run any D16Z6 cam in it with the correct cam gear or adjustable.

OBD2 has 3-stage vtec that's why there are no cams for it. you will have to figure out how to activate the second/third stage vtec spool solenoid and that is where the headache comes from. it can be done but how far do you want to get into it?

do some research. the 3-stage is just an economy thing if i were you and wanted to run that engine i would simply drop a y8 head on it and call it a day. then you only have to worry about mechanical timing. most people give up on the 3-stage vtec d15b that's why there is not much info on it. your best bet is to get a hondata s300 and connect the extra spool valve to IAB since it's an RPM activated switch. for that you will need a conversion harness and a relay.
I did do research on the 3 stg not a lot of info on it unlike the obd1. But I was currently running the 3 stage with my s300 in a p28 it was real good on gas but I switched the vtec solenoid with my y8 solenoid and when vtec cranks that shit got balls bro. I've smoked d16 in hatchs, ef's. I have a 96 coupe with full interior and system and I still haven't seen a d16 catch up to me. I even ran a ls vtec coupe and got him by a fender. So I know this lil engine has alot of potential
 

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There are a lot of factors at play a beat down ls compared to a healthy d15 may be the answer. driving style etc...

I would have to say a y8 has more potential since you can install a more aggressive cam on it where the D15b will be limited to the oem cam. I got a D16 you can try to catch up to ;)
 

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Discussion Starter #15
So back to my question. Do u think I would have a problem with the piston and rod choice. And as for the head. I can just swap my y8 head into it.
 

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Discussion Starter #19
What type of problems. I did some more research some are saying I might have to low of a compression other say I might get 9:5:1 or 9:1. Due to my head but not a lot off people have built this engine so now I'm stuck
 

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measure the rod journals, if they match the mains, your good to use z6. if they are 10-20 thou smaller, they are the z1 style.

i got my $ on same as the mains.
 
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