Funkmaster Ferio

Just curious on what is the largest bore you can safely give a d15(d15z1 to be exact). Could you possible get 81mm out of it if you fill the block to bring some strength back to the sleeves. I know it's 6mm's but there's still hope isn't there? lol. I know I'll get the whole why a d15? I'm getting this shortblock for free and it's the odd ball of the d15/d16 . Almost thinking of a b16 rod/1g supra piston setup if exteme boring isn't feasible. That VX block won't know what hit it!

shamoo

Well, Honda recommends a maximum bore size of 0.020 inches over (0.5 mm) on stock sleeves. This is to repair any cylinder wall damage, and wasn't really intended for increasing displacement.

Even with aftermarket ductile iron sleeves, going to a full 81mm is over 6mm, which isn't really feasible. 1.8L block owners go a maximum of 84.5 (usually only to 84mm) which is only 3-3.5mm.

I know you're getting the shortblock for free, but even if you paid for it, isn't it only a couple hundred bucks at best? Why don't you spring for an "entry level" B-series like an LS (B18B)? Those are like less than $800 (full swap) if you look around. Plus, even if it were possible to go the extra 6-6.5mm, the added cost of sleeving your D-series would be over $800+.

Mr.Mugen

Overboring a engine can actually create more trouble for you than its really worth in the long run - mostly overheating problems which is bad for any motor even more so on a street / daily driven car ...

In my opinion you'd be better off saving your money on other worth while mods rather than trying to get displacement out of a motor that lacks it in the first place - even though displacement isn't a D15's strong suit don't loose faith bro there is quite a few people who rock d series turbo set up's that make decent power even this one guy whos got a STOCK BLOCK in his turbo Vx hatchy thats teering on hitting 11's in the quarter which is no easy feat even if you had a built b-series motor ... heres the link with one of the cleanest Vx's I've ever seen :https://honda-tech.com/zerothread?id=1356768

Now onto a more technical hopefully helpful plan for your free Vx motor I'm a b-series guy so I'm limited on what I know really but my buddy that's into d series power plants told me a while back that even though the 1.5 vtec e motor has less cc's in displacement it has a crank that is 2lbs. lighter than a 1.6 sohc D16Z6 so it is like having a lightened crank from the factory which rev's up alot quicker than even a b sereis due to its lighter rotational mass etc. etc. which I'd think would be great for turbo application's ....

Heres what I would do if I was in your shoes honestly since the vtec e motor didn't put out much more than 90hp or something like that I'd replace the crappy 1.5 economy head with a D16Z6 ( I've seen them go for 100$ ) which would put it around a JDM D15B's power rating which I believe is aropund 130 hp - while I was at it I'd replace the head gasket with a slightly thicker and better Cometic gasket and a set of ARP head studs ( which cost around 85$ ) this will let you run a decent amount of boost later on if you wanted too ... for less than the 800$+ rebuild/bore job on the block you can do the 1.6 head swap head gasket and studs and piece together a junk yard turbo set up out of a HF manifold e-bay adapter plate and a 14b turbo off a DSM and be good to go bro ....

If you really want to go all out crazy or spend some money just port and polish the head do some valve springs and retainers or get a nice blingy name brand turbo kit .... let me know if I can help you source any info or parts brotha !!!


Modified by Mr.Mugen at 8:43 PM 11/16/2005

Funkmaster Ferio

I used to have stockpiles of d15 blocks and just recently gave them all away so I could of just broke out my ruler and seen if a 6mm bore or a even a 4mm was even possible on the stock sleeves. I was planning on just using the stock sleeves and filling the block with Devcon Block Filler or the Moroso block filler to hold those sleeves together instead of having it sent out to have some aftermarket sleeves installed. Way beyond my budget and a just sold my LS with forged internals so I'm just looking to do a extreme budget build. Strictly OEM parts. Now after further researching I guess I need a D15b crank instead of the VX since their not the same and won't work with the rods I had planned for.

Funkmaster Ferio

So could I squeeze 4mm out of it and bore it out to 79mm if I filled the block with Devcon or Moroso block filler instead of sleeving it?