vtec
 

what one is better y8 or z6? cylinder head

Re: vtec
 

y8 for me

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Y8 has better designed combustion chambers...squared off. Means better quench, they also flow better than the z6's. Supposedly might also have a slightly larger cam, but i've never taken the calipers to a z6 cam and a y8 cam to find out, so it's just speculation.

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the one you can score cheaper, I think the y8 works better with a obd0 dizzy but I have only used a z6 so I am not 100%

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y8 ^^^^they said it all

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i was just woundering cuz my car came with the z6 swap all ready in it

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ive read up on this topic a bit, and heres my conclusion.........
both heads have their strong and weak points. ironically, the pros and cons of each head mirror each other. the y8 head has a pent roof combustion chamber design. the large,flat quench pads ensure combustion happens in the center of the chamber for a quicker, more controlled burn.
the downside to the y8 head is that the right side of the splitter is in the intake ports. the air makes a steep right turn in the head, which is intended to promote the "swirl effect". it works well-in stock motor @ 3,000 rpm. in a motor modified for performance, it just gets in the way of flow. there isnt much you can do without "hogging out" the port, which is also counter productive.
fortunately the z6 head didnt have the swirl port design. unfortunately, it didnt have the quench pad combustion chamber, either.
the 2 heads in stock form make nearly identical power. but the z6 head will outflow the y8 due to the y8 swirl splitter design.

Re: vtec
 

somepeople here pull ---- out of their ass, the z6 is better, goto sohchonda.org, the owner there is a very good friend of mine and have many comparisons clearly stating the z6 is better. but drunkinmaster1, got it right, everyone else was pulling opinions out of their ass

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this is good stuff since i've been chasing a d series vtec head to mini-me this thing, :6 mad 3rd gear vtec scream down I-5 :6

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SOHC VTEC is over rated. A6/ZC head outflows Z6/Y8 with boost.

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sohc vtec is as noticable as those electric superchargers :-\

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the z6 is still the best flowing head that honda made for sohc, better than the a6. someone whos done alot of research like abaz whould confirm this.

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No, it's not. A6 is better, SOHC ZC is about the equivilant. Ask J. Davis about the Z6 his friend swapped in place of an A6 and lost power all over the map.

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great thread! i am going with a a6 head on a z6 block. with all the reading ive done this seems to be the best bet. non vtec that is

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Yay for low compression setups!

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and then im goona boost it. im giving up on the N/A .

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either way youre gonna be fine. id be more worried about getting it tunned right than the heads.thats were youre gonna make your power, tunning. and yes theyre low compression which is good for boosting.

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Stock Z6 outflows ported Y8.

Now, Bisi would tell you that a larger diameter curved pipe can be made to flow nearly identical to a smaller diameter straight pipe. However, getting someone who knows how to hog the hell out of Y8 ports to mimick this... good luck, guys.

A6 outflows Z6 right up until the smaller intake valves acts as a restriction. Then you upgrade the valves and ---- VTEC. Ask MAX_CFM about this, Minor, I'd trust him on the LS-->ZC valve interchange being subject to bore shrouding, to boot. :P

By bringing in OMG VTEC a little earlier on Atlee's Z6, we were able to get ~4 psi more boost a thousand or so rpms earlier. This is so important, because the pristine super clean low mileage Z6 made noticeably less power than his high mileage ZC that kept shitting #1 rod bearings. This is because OMG VTEC sucks.

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Heh.

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Yeah, as soon as the head is apart I'm gonna grab an LS intake + exhaust valve and bring it to the guy who's doing my machine work. If it's not going to cost and arm and a leg, I'll run 'em.

PS: WTB LS valves

Re: vtec
 

I have spare LS valves, free.

Should be in a box, in the back of the CRX, next to the Z6 head, 45 minutes from here.

You still want to buy a set from someone else? Getting anything from me is like xmas...

Re: vtec
 

so, how does a dohc zc head flow? Didn't know you could put ls valves in a zc.

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ZC head should flow just as well or better than A6. Havn't got the head apart and down to the machine shop yet, so don't go ------ing around that LS valves are a straight drop in, it might not wind up being worth it for your average junkyard setup. ;)

Re: vtec
 

Stock for stock, ZC head is king dick of D-series.

Stepped on... it falls short of A6.