JDM d15b information
 

Hey guys. I'm sorta looking at doing something for my engine, and since a turbo is down the road a ways, I figure a small motor swap would be ok for now. The motor would be going into a 1988 CRX SI. So I've been looking around and I've come to two possible motor's I would swap in.

First there is the infamous D16z6.
Then we have the JDM d15b.

How different are the two motors as far as power, gas mileage, etc. is concerned? Secondly, how hard is it to swap either of them in? Is one easier to change over than the other? The reason I'm leaning more towards the JDM d15b is because apparently there is a deal on them now in the classifieds on this site. So does anyone have any experience with them? Anyone know how well they run? Please let me know any and all information if you know anything! Thanks.

Blaine

Re:JDM d15b information
 

the d15b runs great boosted, i ran one for a while.

only problem is the aftermarket support for it, or even oe replacement. break some ringlands and good luck finding another p08 piston for it.

I say the z6 all the way, it just makes more sense and is less of a headache.

Re:JDM d15b information
 

I use to get them for 250 a pop that was the swap of choice for the budget guys when I was doin swaps for people. Very good motor cant go wrong with either. Same hp #'s the d15b is more rev happy but in the long run whatever is a better deal but the lack of support for the d15b shortblock does hinder if you plan on building one

Re:JDM d15b information
 

Okay I was doing a little more research and apparently the JDM d15b can use aftermarket d16z6 rods/pistons? I was under the impression this wouldn't work... ???

Re:JDM d15b information
 

no they cant. z6 pistons would stick 3mm out of the block.
maybe z6 pistons on d15b7 rods or something.

Re:JDM d15b information
 

http://www.honda-tech.com/zerothread?id=680621

here read my discussion if you wanto know, ive put in the leg work, d16 pistons will work fine in a d15bvtec, essentially the d15bvtec block has the same deckheight as a vx block, has the same stroke as a 1.5 and 1.6 length rods but the rod journal sizes is the same as the 1.6 which is very "different"

please tell me how you got 3mm sticking out, i think you should try the math

yes there is a 3mm difference in pin height is from d15s to d16s EXCEPT for vx's which have the same pin height as a d16

and i would be willing to bet a 12pack of beer that p08 d15bvtec pistons have the same pin height as the d16s just like the vx's

bc if what your saying is true than the idea of vx rods with d16 pistons in a 1.5 wont work either, which would not be true

im not trying to be an ass, just trying to clarify and confirm truths and deny "rumors" and "assumptions" that are and have been circulating honda-tech,sohchonda,d-series.org,and other places

i hope that this has been helpful for all

Re:JDM d15b information
 

I disagree.

If you hold a z6 p2 slug next to a p08 d15b slug, the z6 has a lower pin location and the distance on the z6 from pin to piston top is significantly higher. Therefore if you put them on the hdm d15b rods, they would probably stick out of the block. If I had a z6 piston laying around I'd snap a comparison pic to show you what I mean.

Now if you were to find a shorter rod than the jdm d15b vtec rod, you might get them to work.

And I don't believe you can use any d16 rods in the jdm d15b, as the journal sizes are larger on the d16 than the d15b. We were gonna give this a go a while back when I toasted my ringlands but just looking at them we could see the difference, and a few honda-tech posts confirmed what I thought so we bagged that idea, and thats where my 6 month long motor dilemna started.

Re:JDM d15b information
 

as my pictures and measurements show d15bvtec rod big ends are in Fact 48mm w/o bearings and 45mm w/bearings just as a d16

it sounds to me that if you the rods wouldnt fit your really didnt have a d15bvtec motor you had just a usdm d15 motor espically considering you said the wrist pin height was different, i can compare the wrist pins of my vx pistons and zc pistons and you can see CLEARLY that they are the same height, and the vx block is the same as the d15bvtec other than the d15bvtec having bigger rod journals

Re:JDM d15b information
 

I wasnt trying to make rods fit. I was trying to make pistons fit. I know what motor I had. I may be wrong about the rods but like I said, holding a Z6 p28 beside a d15b vtec p08 showed very unsimilar results. Next time I am up at Pats, I'll grab one of his p28's and my p08 and show you what I mean.

Re:JDM d15b information
 

cool good id love to see the p08 out of a block, maybe i will see if i can get the administrator of sohchonda.com (4dr) to get his ass in gear and just take his apart and get the piston measurements for us

btw ive invited him over here, he says he cant view the site for some weird reason, any ideas?