oem pistons in d15b7 block..

[vpSPOONsol]

sup, im building up a mini-me d15b7, and i want to know what oem rods or pistons can i put into the b7 block to handle higher revs? thanks....
i have access to sohc ZC engines over here..

 

[brian11to1]

UHmmm... any d series sohc most likely. why OEM?

 

[liquid00meth]

your piston has nothing to do with how high your motor can rev. You want to look at aftermarket rods.

 

[brian11to1]

Yes aftermarket... IB Spec, Eagle... etc... Check in to em.

 

[vpSPOONsol]

i want oem rods cuz i can get them for cheap, correct me if im wrong, but i heard that ls rods fit the the d block, with minor mods...

also, i didn't want to even touch the block at all and just work on the head, but since ill have the head off i minus well put a lil money into the block

 

[liquid00meth]

I'm honestly not sure what pistons are the best to use in a D. I know I have heard of people going with the ZCs though. Someone around here knows.

 

[phunky.buddha]

If you have access to a SOHC ZC for cheap, build that block and forget about your D15. You'll get more displacement with the SOHC ZC (1.6L) and have a stronger block and more aftermarket support.

The LS rods will only work in the D16 (or SOHC ZC), but aren't necessary (or desirable, too heavy) for an NA D build.

Run the SOHC ZC bottom end, DOHC ZC pistons (PM7 or P29), a Z6 (12.0:1 comp) or Y8 (12.6:1 comp) head, Y8 manifold and a nice cam like the Crower Stage 3 plus matching valvetrain. You could be done for $1000 in parts if you shop around a bit.

That combo can easily put out 160whp if you tune it well, and it would all be built from OEM parts except for the cam and valvetrain.

 

[vpSPOONsol]

thanks, that was the post i was looking for, but will the dohc zc pistons fit my b7 block. reason is that i plan to bring my car back to cali with me, and dont wanna fail smog cause of a different block number. i also get a big discount on roadtax over here cuz of the 1.5l opposed to a 1.6l.
also, will the stage 3 cams compromise everyday driveability? thanks!

 

[phunky.buddha]

Oh, I see. The DOHC ZC pistons will work in your D15, but I don't know what the compression would be off the top of my head. I'll have to do some quick math...

If you tune it correctly, the stage 3 cam will be fine on the street. There are a few guys on the D series boards that run the Crower 3 cam on their daily drivers, and supposedly their idle is fine. You might want to run a stage 2 or a Zex cam if you're going to try to pass smog in California though- plus your compression with DOHC ZC pistons in the D15 block probably won't be as high, so you may benefit more from a smaller cam.

 

[brian11to1]

I have access to sohc ZC for 175 needs rings... if you want I could buy it then you buy it from me.

 

[phunky.buddha]

Ok- numbers...

D15 block / crank / rods + DOHC ZC pistons + Z6 head + Z6/Y8 head gasket = 10.04:1 compression
D15 block / crank / rods + DOHC ZC pstons + Y8 head + Z6/Y8 head gasket = 10.45:1 compression

D15 block / crank / rods / B7 pistons + Z6 head + Z6/Y8 gasket = 10.11:1 compression
D15 block / crank / rods / B7 pistons + Y8 head + Z6/Y8 gasket = 10.52:1 compression

The D16 pistons have a much lower compression height than the D15 pistons, so you have to have a huge dome to make the same compression ratio numbers. The DOHC ZC pistons' compression height is 1.7mm shorter than the D15B7's, so there's really no point in switching your pistons. Just use the stock pistons you already have and maybe a thin head gasket. If you can get your hands on the 2 layer Y8 gasket and a Y8 head, you'll make:

D15B7 bottom + Y8 head + Y8 2 layer gasket = 10.86:1 compression

Shave the head 5 thousandths and you can get up to 11.01:1 compression easy.

By the way- it slipped by me that you were going to taking this car to California. You won't pass visual inspection with a head swap. I would recommend that you build a D16Z6 outside the car with DOHC ZC pistons, then swap it into the car.

You could also just build the D15B7 without VTEC, but you won't get as big of a power gain. There really aren't any OEM pistons that will increase your compression in the D15B7, although there are quite a few head packages out there which can net you a significant increase in power with the stock pistons and stock head. Look to Exospeed. They've got a ton of great non-VTEC D15 stuff.

 

[krazykoncept]

about using LS rods in the D15, It won't work. The rod end on the crank is smaller. I wanted to do the same. I ended up tossing the D15 and got a D16Z6. I used LS rods refitted end and used the D15B7 pistons (because they are flat tops) and a D16Y8 head. I think i'm getting about 12 to 1 compression. So if you want to build your D15B7 throw in the ZC piston on aftermarket rods, don't need the vtec head, but get a after market cam and port and polish. Also try getting a SI trans with a high final drive to keep the RPMs up. This was my plan to, I just came across ZC pistons, I my do this on the side.

 

[phunky.buddha]

Originally posted by krazykoncept@May 27 2004, 01:57 AM
about using LS rods in the D15, It won't work.

Yes, I said that already.

You actually got your D15 pistons to work in your D16 setup without the tops hitting anything in the head?