z6 here too

 

my Z6 loves the 10psi im throwing at it every day.

 

I got a D15 that's better than both of them

 

Yea, but I can go start my Z6 right now. (and drive it lol) [sm=exactly.gif]

 

You got a JDM D15B right? Weren't the D15's made from 92-95 virtually identical to the z6's, and weren't the D15's made from 96-00 virtually identical to the y8? From what I've read, the 96-00 D15's are only 3hp more and 5trq less than the y8, so not much difference there (D15=1493 cc, D16=1590 cc). What makes it better than the y8 or the z6?

 

I've read the Z6 flows better at higher rpms, and it seems most people I see running D-series motors use the Z6 head. The only application I've seen the Y8 head used well was in the Pinks Full-Race Civic.
It had very aggressive porting though, so high rpm flow was no prob.

The JDM D15B is my favorite D-series motor though. I can't claim it's the best, because I haven't seen enough dynos of them or other D builds. They really seem to have potential though. Shorter stroke, long D16 rods, just seems like a better design. Torque would be lower with them in lower and midrange rpms, but I think it could follow through the high end much better. Might make up for it. I'll find out when I get mine, I guess.

 

More favorable r/s ratio.
More willing to rev and make power higher in the rpm's

I have drove and worked on more Y8's and Z6's then I would even like to remember. This engine pulls harder than either one of them to me. I layed down 122 or so whp and like 114wtq with it with crap ebay bolt ons. That is around 5 to 7hp more than any Z6/Y8 I have ever seen lay down with really high priced name brand bolt ons. I boosted a Y7 which the bottom end is exactly the same as the Y8 with 7psi from a T25 and drove easy on it and treated the engine like gold. Well it spun a berring and crapped a rod into the oil pan. I have hit close to 1 bar on this engine and drove the **** out of it and never had any problems at all with it. Never.

 

If you wanted to get replacement parts for your motor, (i.e. alternator, head gasket, spark plugs, etc...), can you get the same parts that you would get for a z6 or y8 (within the corresponding years)?

One other thing.... If the z6 is better than the y8 for the various reasons stated, would the D15 from 92-95 be better than the D15 from 96-00 for those same reasons?

This is really great info. Thanks for the input everyone.

 

Exactly what Marty said. Shorter stroke with long D16 rods. :drool:

As for parts, I'm not sure. I have a feeling parts from several D-series motors are interchangable with it though, and most if not all parts from a Z6 probably are.

I've read of rare OBD-2 D15Bs (post 96), but for the most part they are OBD-1 (pre 96).

 

The D15B is a oddity so to speak, not that it uses advanced parts or anything like that but here I'll lay it our to you somewhat.

The USDM D15's do in fact have smaller rods vs the D16's. But here is the thing about it, you can not use the crank from a D16 in the jdm D15B as the crank mains are smaller in the JDM engine just as they are on the usdm engines. But here is the kicker, while the crank mains are the same on the usdm and jdm d15 the jdm d15b has the same rod mains as the U.S. D16's. What does this mean?

It means that unlike a USDM D15 you can buy and use D16 aftermarket rods on the JDM D15B. Also to be noted you can not use any off the shelf aftermarket D16 pistons though. The deck is shorter on the D15B there for the piston will actually buldge out of the block smacking the head.

I will write more just give me time.