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Discussion Starter #1 (Edited)
hey guys, i'm doing pnp on my y8 head. i'm wondering for the guys that's done this before what exactly did you guys do with the asymetrical ports of the y8 head.

did you guys keep the swirl theory...as in not aggressively messing with the left side of the port? or did you guys just port the left side and try to make the head a straight through design?

or how about leading the swirl theory to its' full effect. check this: if you were to 1mm bigger the secondary valve it would take the swirl effect to a hole nother level. i'm saying make the swirl bigger! and then design the primary port to shoot into the middle of the swirl. could this posssibly allow for maximum chamber fill and atomization...(best results on a y8 head cause it'll already be shaped to do so.)

picture it like this: you're looking into a tornado from the top (arial view). and from the left air is shot into the tornado via a downward right oblique angle. won't you think this would put more air onto the surface of the ground (piston top). and in one intake stroke this could possibly induce maximum fill into the chamber.
 

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ridin on rotas
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ok, I've been thinking about this. I think I have an answer. if you use one valve bigger than the other, the piston will pull more air through that valve.

so for the secondary(one recieving less air flow) valve was oversized the piston should pull more air through thus more than likely making air flow through both valves equal. This would eliminate the swirl effect making it more like the z6 head.

but if you were to enlarge the primary valve, then more air would be pulled through it and less air pulled through the secondary valve again eliminating the swirl.

I'm sure honda engineers thought of using offset valve sizes, but figured out that it would eliminate the swirl. This would be true, unless the intake port holes were redesigned to alow equal flow to both valves.

so in theory you could run one offset valve size on a z6 head and create swirl. but as we know swirl creates low end torque, but sacrifices high end hp. so this might not be a good ideal on a race car.

I've based all of this on the fact that air and water will follow the path of least restriction. it's why in a swimming pool the return into the pool have smaller and larger "eyes". this allows the water to be returned equally to the pool to help keep the water circulating more evenly for the filtration system to work at it's peak.

please feel free to comment on this or correct me where I might be misguided or wrong
 

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Discussion Starter #3
i figure no matter what air will still be sucked in by the downward force of the piston that the larger valve won't be able to allow enough air in. that would mean some air has to go into the secondary valve. the sucking pressure of the piston would remain the same for both valves but the resistance of air into cylinder would change because of different valve sizes. so in theory more air would go "swirling" in from the primary and still there will be a substantial amount of air that will enter the secondary valve. and because the offset is 1mm larger that high rpms won't be too shabby.

i was looking at the diy port and polishing forum and came across what i think was an old endyne or whatever picture of one of their cylinder heads. that's where i got this idea from.
 

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Discussion Starter #6
nah no pictures but i do have my old head right next to the head i'm porting now so i can compare them.

i've looked at alot of the port and polish intake ports of other d heads and none of them look the same as the y8 ;it's slanted to the right.

a friend of mines who runs 13's on an all oem internal lsvtec (no slicks) said that he favors the y8 due to the higher compression and the swirl affect. he's ported many y8 heads before and i've been in the cars that the ported heads were in and the low end torque was noticeable. "swirl" i think is a really affectinate way of porting the head especially the y8 due to it already being like that.
 

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allwheeldriveturboboxer
'08 Mazdaspeed3
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Arachnid said:
nah no pictures but i do have my old head right next to the head i'm porting now so i can compare them.

i've looked at alot of the port and polish intake ports of other d heads and none of them look the same as the y8 ;it's slanted to the right.

a friend of mines who runs 13's on an all oem internal lsvtec (no slicks) said that he favors the y8 due to the higher compression and the swirl affect. he's ported many y8 heads before and i've been in the cars that the ported heads were in and the low end torque was noticeable. "swirl" i think is a really affectinate way of porting the head especially the y8 due to it already being like that.
Let me rephrase what i said previously; With my head, I just made sure they were opened up as evenly as possible to keep the swirl; I seriously cant imagine how you could eliminate that, they are too offset. The valve idea is an interesting one, i'd have to really think about that one before i commented further. I would like to note that 2 of the most noteable D head porters, Bill Gude & Javier Gutierrez all have recently told me they prefer the y8 head over the z6, when ported...mainly because of the combustion chamber design, however, they did not mention any other reason for the preference. Also, the CRX 'drag project' featured @ www.speedmachineperformance.com uses a y8 head for its 181 whp.
 
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