[Syn]

I recently got a Dohc Zc and I would like to know what my options are. From What I can tell Turbo is a good way to go. I would like to get 200+ whp in the end and be able to daily drive the car. The ZC I got was already on its way to being turbo ready and i want to know if everything that has been done is actually on the right path. I am a really curious because the owner befor me did all the work on it as follows

-CRC Vitara pistons
-Nippon rings
-Fj custom length forged rods
-ARP head studs
-ACL rod bearings
-Cometic head gasket
-block notched to clear larger connecting rods
-Block bored .5mm over and bores aligned
-cylinders are .034 larger diameter of piston to allow expansion in high boost
-head milled 2mm
-hand-lapped valve job
-ported intake and exhaust runners
-micro polished crank

This is what i know. The guy I bought it from said it was turbo ready but I have seen a lot of posts that say vitara and dohc zc are bad and what not. It is in my 89 crx si now and I am running it n/a atm. If anyone could let me know it is ready for turbo or not as this is my first turbo project and im as new as it gets. thanks

 

[firsteg]

vitara's and DOHC d is not a good combo. the combustion chamber in the head is quite large and will give you a very low compression ratio. better bet is to get a smaller dish forged piston. they are a little more expensive but they are stronger and more resilant to detonation.

if you go wil low compression your car will be gutless when it's not in boost and result in a slightly slower spool time for the turbo.

try find a set up that will be around 9.5:1 compression. personlay i wouldn't go below 8.8:1

i'm not sure what you have for tuning, but it is pretty much the most important part. look into it now and the cost before you commit to turbo parts.

this site is really useful for finding compression ratio's

Honda D-Series Compression Calculator by ZealAutowerks

 

[The_Acid_Beaver]

With the head milled 2mm . . . this is almost acceptable.

 

[cory jordan]

*side note* anyone notice the recent influx of dohc zc love lately... or the interest?.. just putting it out there.

that build seems to be pretty spot on, sans the vitara pistons .. compression shouldnt be crazy low with the head milled that much. what are the length of the rods?

 

[DDream]

Im looking to build my ZC as well but with higher compression pistons with the fjr spec rods.... only thing im wondering and you should as well is if we would have to notch our blocks

from what i understand all d series need notched except d15

i have y8 vitara build with eagle rods waiting for its time but that is the one thing i really hated doing... especially since i got it bored honed and decked then realized the rods didnt clear so i had to pretty much restart after i notched

 

[The_Acid_Beaver]

*side note* anyone notice the recent influx of dohc zc love lately... or the interest?.. just putting it out there.

that build seems to be pretty spot on, sans the vitara pistons .. compression shouldnt be crazy low with the head milled that much. what are the length of the rods?

They are getting to be super cheap again. It is cyclical. No one wants them, so guys grab them for cheap and even some people think they are getting an LS. heh

I still don't like Vitaras especially in a DOHC D, but milling the head that much is a good start.

I really, really can't stress this enough: If you are building a DOHC D, get the Race Engineering D16A1 pistons on standard rods. Spend the extra money now and NEVER have to worry about your bottom end again, unless you are aiming for 500+.

You will have to notch the block with the FJR-spec rods. How do I know? I have a block sitting in my shop with them for notching. heh

 

[Syn]

I believe I am at 8.6:1 as far as compression.