stock d16z6 and the d15b vtec(w/pm6 rods) - w/ p29 dome pistons

[readallen]

what compression ratio does this produce and can it run still 87 octane, and most importantly - would it be worth it(cost vs. hp gains) on ebay there 65 to 135 dollars?

[FrodoGT]

Im not quite sure what your asking here but ill try to answer. The z6 is a stock 9.1 compression. The d15B is a z6 with a shorter stroke, everything else is identical except the crank and maybe the cam. The rods are the same and putting p29 pistons in there will take you to 12.8:1 CR, which yes will require at minimum 93 octane and WILL REQUIRE IT TO BE TUNED!!! That is most important.

[readallen]

I have been researching and this is a can of worms - so i'm going to run stock for now , I have a D15B vtec and a d16z6 and haven't decided which to drop in, I have a si trans, zif socketed p28 ecu(also have a6 dizzy and pm6 if wanted to go that route), wiring plugs, ect.. except for a d16 exaust manifold.

I know you have the d16y8 with a s300 but in my shoes which would you run stock possible light mods in future as a daily driver? thankyou

[Tony]

Basically the D15b and the D16z6 are essentially the same engine....yes there are differences, but about the same outcome with them.

If you are wanting to go the P29 route on the pistons, go with the P28...hell any route you go, go with the P28, they can be used on just about any engine if they are chipped and tuned.

I would go with which ever engine you want, don't worry about a stock exhaust manifold, just get an aftermarket header. I have seen way too many cracked D16 exhaust manifolds too even mess with them now. Go with your P28 ECU and just run it like it is. When you want to upgrade it, its easy to upgrade.

If you want to just toss some minor mods on it, you can. If you want to toss some major mods like the P29s in it, you can. Either way, its easy to do what you want and then go get it tuned.

[readallen]

which one is more dependable / lasts longer for city and expressway driving- and would there be a difference between the mpg that they get?

thanks tony right now Im leaning towards the z6

[Tony]

Like I said, basically they are the same engine, just one we got over here, and one we didn't.

I would just go with whichever has the least amount of miles on it. Go ahead and replace the usual stuff while you have it out: timing belt, tensioner, water pump, any gaskets or seals you see leaking.

[FrodoGT]

Hes right, except for the crankshaft specs (1.5l stroke vs 1.6) and block to match, they are identical parts (cam might be different specs but are interchangeable). Everything else is the same. Casting numbers and all. However since its a smaller displ. the d15 wont run exactly perfectly on the stock p28 like a z6 would so I suggest if you plan to drive the car before it gets tuned go with the z6.