Hi I'm fixing to start buying parts, need a little advise. I'm debating on weather to use a y8 or the z6. Or even a combination over both. What r everyone's thoughts?

 

The most cursory of effort would tell you that the Z6 crank is easily superior to the Y8.

https://honda-tech.com/honda-civic-d...sting-3002401/

https://honda-tech.com/honda-civic-d...tions-1998336/

These threads are not optional reading.

 

I'm buying the crank rods and pistons. Talking about block, head and intake.

 

Buying an aftermarket crank? Don't waste your money. The OEM crank has been proven up to four digits of power. There's no reason to replace it unless you're going for those power levels, and if you were, you wouldn't be asking these questions.

The most cursory of searches will show you these threads, which will directly answer your questions about the head and intake.

https://honda-tech.com/honda-civic-d...w-wise-540355/

Z6 or Y8 head? Pros/Cons | Onecamonly

Z6 or Y8 head better for turbo? - Honda Forum : Honda and Acura Car Forums

The block, it's all 6 of one, half dozen the other.

 

Thanks man. I'm new.

 

/thread

Easily searchable. Most go with z6 block and head.

 

z6 no doubt. forget about torque though. i used to have one. damn thing was literally gutless until the rev counter turned over 4000 rpm.

 

Just picked up a z6 block head and intake. Block has $700 worth of machine work done to it. Got them for $275. Score!!!!!!!

 

while its no b20, those sohc vtecs make a fair amount of tq per hp, moreso than b series vtecs. it just takes more boost to get to your number goals.
the demise of the sohcs (beside y8 cranks and head lift) is the gearing. a d2b setup will do wonders im sure. if you have an ef i think you can use the relatively close geared zc or d16a1 tranny from the late 80s teg.

my first turbo car ever was a 93 ex with the stock z6. this was 12 years ago. with a good complimentary setup and a 60 trim t3 it picked up smooth right through the powerband. if your turbo is too laggy it will feel like it. also those darn vitara motors are slow because of low static compression. even with like 5 degrees more timing in vacuum than the stock map and a light weight eg chassis the vitara build z6 i had about 5 years ago was slow and i would find myself driving around a 5-10" a lot rather than 10-15". this cut down on my mpg but whatever...and for what its worth that vitara build with a td05, ramhorn manifold and stock head made 191/166ftlbs on like 8 psi and was making over 240tq and 250+hp by 14 psi.

 

There isn't much of a difference between a z6 and y8 block except for the y8 being an obd2 block with provisions for a knock sensor and so on. Head difference isn't enough to warrant going out of your way to find one over the other.

The main difference is the oiling system. The y8 crank only has one oiling hole per journal while the z6 has two. Almost everyone puts a z6 crank in a y8 block, it is a direct replacement after all. The oil pumps are virtually identical, the only differences being the dipstick placement (z6 is centered on the exhaust side of the motor, the y8 has one on the oil pump cover) and the OBD2 pump having mounting provisions for the CKF pickup.

The only thing I would suggest is porting the pump, the sohc motors need all of the love they can get.


Also the more important question is why are you buying parts already? You've admitted to being new which is blatantly obvious so listen to us:

Until you have decided on a power goal and purpose for the car you cannot decide on what parts you need and don't need.

If you want more than 220-230hp and have the car being reliable then you need pistons and rods. D series rods are notoriously skinny and after the low to mid 200s it's really only a matter of when, not if, one or more rods fails.

What do you mean by "machine" work? Do you know what was done? If it's a stock sleeve motor then I find it very hard to believe that much has been done to the block because there isn't much to modify.

Don't run super low compression. With the advances in fuels, materials, and engine managent running low compression is pointless. Higher compression means better efficiency, more power per lb of boost pressure (dependent on turbo sizing, fuel and ignition timing, compressor/turbine wheel efficiency, and so on). Don't go lower than 10:1 for a pump gas car, e85 can easily support 13:1 turbocharged motors. The fuel in your area will dictate what a safe compression ratio and power limit are.

Get it tuned. Don't just chuck a basemap in it and go beat on it. Since you're building a new motor you have to keep in mind that a break in is mandatory. If you fail to follow proper break in methods then you motor will more than likely suffer in terms of performance. Find an experienced tuner in your area and have them work their magic.

Last but certainly the most important. Read the Forced Induction FAQs stickied at the top of this forum. Read them at least twice before committing to a power level and buying parts because depending on what your goals wind up being there's a high possibility than anything you purchased before that point is no longer usable.

 

Thanks for the very helpful post.