Hey guys, building an OBD0 DOHC ZC for boost. Goal is 250 whp with room to grow.

I'm starting with a bone stock bottom end, head is already built w/ cams, cam gears, valves, stem seals, retainers, springs, port/polish.

Parts Ordered:
-ZC Motor/Trans
-Head Gasket
-Timing Belt
-Water Pump
-Intake Manifold Gasket
-Exhaust Manifold Gasket
-Valve Cover Gasket
-Valve Cover Gasket Stud Grommets
-Rear Main Seal
-Oil Pan Gasket
-Timing Belt Tensioner
-PM7 Socketed w/ stock ZC spec chip
-Spark Plugs
-Oil/Filter

What I need:
-Pistons
-Connecting Rods
-Rod bearings
-Piston Rings
-Throttle Body Gasket (Honda discontinued)

Now my questions:
1. I'm using a known good block. Will it be okay to go ahead with the stock sized 75mm pistons? Or should I get an oversized 75.5mm in case of needing to bore?

2. Going with Manley rods/Vitara Pistions @ 8.5-1 CR for boost. I see these are very common pistons to go with, are there any other recommendations for cheaper or in the same price range?

3. Where the hell do I find a throttle body gasket?

4. Is a socketed ECU all I need? Any better options for getting it Dyno-tuned? Price is a factor here, but I will pay for what is needed.

5. On stock ZC fuel maps, will this run like crap NA until I put the turbo on? I MIGHT have to wait for my turbo, so far the build is going over budget and might not have enough for the nicer turbo that I want.

If I missed any huge points or parts, please let me know. I have a technician who has built numerous motors who is helping me, I am doing as much research as I can beforehand though.

Thanks.

 

Any time you lower the compression ratio in a car like that, driving out of boost (or na in general) will be more than likely be sluggish compared to how it is now.

Probably better to get the block honed and make sure it's in spec for stock bore (75mm).

Felpro makes a throttle body gasket. For some d-series motors it's the same as the F series SOHC throttle body. Local parts store should be able to get it for you.

 

What I am running now is a bone stock DOHC ZC. What I will have to start is a built bottom end on a different ZC block and built head. Everything is getting machined aside from the head which already is.

I haven't been able to locate this throttle body gasket either.

With a built head, even with lower compression, and base maps from my friend's tuner it is impossible for this thing to be slower than my current ~99whp DOHC ZC. Sluggish yes, but that is relative.

It's my DD. I might not have enough to go for the turbo I want right away,

 

Hey guys bumping for help:

Updated parts list:
-ZC Motor/Trans
-Head gasket
-Timing Belt
-Water Pump
-Intake Manifold Gasket
-Exhaust Manifold Gasket
-Throttle Body Gasket
-Valve Cover Gasket
-Valve Cover Stud Grommets
-Spark Plug Tube Seals
-Rear Main Seal
-Oil Pan Gasket
-Timing Belt Tensioner
-Oil - Mobil Super
-Coolant
-Honda Genuine MTF
-DOT 4 BSF
-Pistons/Rings - Vitara
-Rod Bearings
-H-Beam Rods
-ARP Head Bolts
-ARP Rod Bolts
-NGK V-Power Plugs
-Front Crank Seal
-Camshaft Seals
-Oil Pump
-XTD Stage 3 6-Puck Sprung Clutch
-8 lbs. Flywheel
-RDX OEM 410cc Injectors
-Walbro 255 lph.
-PM7 Socketed ECU

Anything I am missing that you guys can see?

Thanks in advance. Only thing not included is the machine shop fees, don't know much other than a guesstimate yet.

 

Sounds like a very solid list. You don't necessarily need RDX injectors. Blue top DSM (450cc) can be found cheap and even then you can send them somewhere to get serviced for like 10-12$ per injector.

Don't forget your crankshaft main bearings as well. If you plan to do the vitara setup, check out the rod+piston+rings combo available on p2p0.org. That's where I'm purchasing from when I get my taxes done for my z6 build.

 

With vitaras and no turbo yet Ull make maybe 100 hp at redline... If u really love this motor and r gonna spend this much money get real pistons and keep the comp higher for drivability outside of boost

 

^^ the guy above has never had a vitara setup obviously

Ive had 2 vitara motors now, both with standard length rods (which means mid 7:1 compression ratio) and the car is PERFECTLY peppy while not in boost, barely rev the car to 3k to accelerate with traffic, plenty of power and good gas mileage to boot.

My vitara block I have waiting to go in is P2P extended length rods, so 9:1 compression, but I only went that way since he had a sale. My low comp motor is still installed and took a 20+ psi beating from a t3/t04b all year every day

 

Definitely going to look into those injectors. By any chance do you know if the ZC crank main bearings are the same as any D-series? Going to check out the rod/piston/rings combo as well. I think right now for rods/piston/rings/ARP rod bolts I am paying $409.

Also, I might have to run this with no turbo for 2-3 weeks. Even with a base map tune, the power might be that bad? Doesn't make so much sense to me. :/ I am still new at this. What is the benefit to running higher compression on boost? Any reliability issues?

 

This gives me hope! I have a heavy foot and want to beat on this motor daily. Even if this thing is a dog non-turbo, I guess I will have to deal with it. Too bad I probably wont have this done and broken in by the time IFO Gainesvill rolls around

 

Here's another excellent case where someone used the performance 2.0 (p2p or p2p0.org) combo like I talked about earlier.

Vitara pistons, while using the same bore as d16/zc motors like ours, probably depend on a longer rod stroke in their intended application. Stock rods with Vitara pistons will drop the compression ratio DRASTICALLY reduce the compression ratio. Using them in conjunction with custom length rods (FJ spec, which the p2p rods are modeled after) can bump the compression ratio by ALMOST A WHOLE POINT. I actually just tested it out to compare compression ratios between stock rod (length) or custom.

I mimicked my planned setup (75.5 bore, 138.63mm rods, vitara piston, left the rest at defaults) and the static comp ratio was 8.5:1. When substituting in the stock rod length, the compression ratio drops to 7.6:1.

Vitara pistons are NOT meant for stock length rods. Drivability out of boost, spool times, and other characteristics will be directly affected by this. Play around with the numbers and combinations you can make to see what I mean. This is an infinitely useful tool.

http://www.zealautowerks.com/dseries.html <-- d-series compression calculator

*Whoops* I misread earlier. I'm surprised to see that your engine was so peppy using stock length rods. Would you go with stock length or custom length rods if you had the choice?

 

^^^^very surprising with stock rod length

 

Probably a noob question, but, my main concern is dependability. I'm shooting for a dependable 250-280 WHP setup. What effect will the higher compression have on how dependable the build is? I'm doing everything the right way, and the price is the same either way. So can I still have a weekend race car and dependable DD with a higher CR 8.5/9-1?

 

I plan on making more power later on, but this is a start.

 

Higher compression means less work for the turbo to make ur power range

 

I feel like one of the most important things it affects is how much boost you can push safely. That compression ratio paired with your turbo choice will make all the difference when you decide to up your boost/power.

They say never base your goals on a boost number. But once you have an engine built, you may have to settle for a (maximum SAFE) boost pressure for your particular turbo and see what power you make their rather than a power number and changing everything to accommodate to that.

 

with a dohc zc head u will be 6.5:1 thats a no go u can mill alot off those heads to raise the comp some but you are better off getting a piston with alot high comp

 

So I'd rather not mil the head, custom length rods? I'm checking some options now.

 

U will be 7.4 to 1 you need forged pistons I am actually selling a set but they are bigger than you are looking for but a arias off the shelf piston will give you what you want

 

The ones on p2p0.com custom length rods/vitara pistons advertise 8.5:1 CR. Is this not true? Will I really be in the 6s/7s?

 

On a sohc it would be that high but not with a dohc zc

 

damn... So milling my head or higher comp pistons are the only option right now?

Also an update:
Picked up the new motor/trans today. Tore it down, no visible scaring on cylinder walls, very slight scaring on crank from one bearing, and one holed piston. Hopefully wont need oversized rod bearings, but not the worst that can happen. Going to take it all to the machine shop tomorrow and see what the guy would do about milling my head.

 

SodaZC, I have a nice combo for you if your interested for your setup. I have AEM EMS series 1 and ill include FIC 650CC high impedance injectors with plugs for harness both for 650.

 

That ems is probably too much for his needs. A chipped stock ecu will work just fine...

 

yes really is the only option you should look at anyway since all the new sets of vitara pistons have been cracking. you can also stroke the engine but thats going to cost alot more just for the sake of using vitaras

 

I just built a turbo ZC with vitaras

PnP head

port matched manifold and tb
crower custom grind cams
vitara pistons
eagle rods
motor is for sale but im trying to piece together a turbo kit so I can install it