I have a 92 civic Vx with a z6 tranny and a z6 ecu, i didnt swap out the head but i have a z6 head, and ECU, i put the ecu in a it runs great, should i swap the heads out too? also, can i put any D16 pistons in a D15?

 

yes put the head on if u have it. and u cant use the d16 psiotns unless u bore it

 

i heard the vx motor would produce to low of a cr to run it. Not sure if i am mistaken though.

read this:

https://honda-tech.com/zerothread?id=554053

 

but i was pretty sure that the difference between a D15 and a D16 was the rods and that the pistons were the same bore, the extra displacement was due to rod length

 

Using the Z6 head on a Z1 will net somewhere between 8.2:1 and 8.4:1, depending on gaskets used. Not very good for performance, it will run, but not be as powerfull as it could. Something else that's really not good is using the Z6 (P28) ecu on the Z1 (which should be using the P07) - you'll actually be MUCH slower in this configuration (and, you are probably getting a check engine light due to the O2 sensor wiring difference to boot). This is because of how the VTEC-E engine operates.

First of all, let me help with some misconception:

VTEC-E works differently than VTEC. At low RPM, the primary intake valve operates normally but the secondary intake valve opens only enough to keep fuel from accumulating on that valve. At the P07's VTEC engagement point, about 2500 rpm, if you have the proper requisites (high engine load, proper temp an oil pressure) it will switch to "normal" operation on both intake valves.

You will feel a big "kick" if you use a P28 with a P07 head because you are choking the motor until the other valve is active. It will feel like a big kick only because you are so far down on power before you activate VTEC. Not because it's faster. I would be slower with the P28.

My advice - put the Z1 computer back in, keep the Z1 head, and enjoy the added performance of the Z6 transmission gearing. If you want to go to true SOHC VTEC operation, please get either a full Z6, D15B, or do a mini-me (using something other than the Z1 as a base). Or, get D15B pistons to go into your D15Z1 - but I've not see this combo tried yet. It, in theory, should net the same compression as the D15B SOHC VTEC.

 

great info

 

great info thank you, what if i replace the pistons with flat top pistons ( i have a set) and do the head swap, i think this will keep a decent compression because VX's have dish pistons, feel free to correct me, by the way, the pistons are out of a D15

 

Can I use a d15z1 trans with a d16z6 engine?

 

Yes.

 

You can but the Z1 trans has totally different gearing than the Z6 trans. It has a 3.25 final drive and huuuuge gaps between gears so it's awful for spirited driving. Amazing highway cruiser though, you can cruise 80mph @ 2500rpm with some big tires.