www.dodo-upgrades.nl

This is a useful link that inform about the options of different versions of
D-series intake manifolds and their components.
http://civic.gotskillslounge.com/civic% ... ldswap.pdf

Nice one!

Very usefull PDF, thanks for share !!

thnx for share)
last news about Y8 IM from Honda-Tech D16Z6 VS D16Y8


We actually tested both manifolds on a flow bench and the z6 flows more cfm then the y8.
Z6 runners are larger than the y8. Y8 has more plenum volume.

there are only slight 2-5 hp gains over 5-6000 rpms the z6 manifold on HIGH horsepower applications. they only slightly change powerband - top end low end power. the bigger plenum is idea is long since been proven that the y8s dont make more horsepower. if you look at the specs of the d16z6 and the d16y8 they are identical up to 2hp which could be thanked for the slightly higher compression and the little bit of more lift the y8 cam has. the manifold doesnt do much... altough the y8 manifold can be bored out to accommodate a larger TB while the z6 cannot. if you compare the z6 vs y8 the z6 flow characteristics are smoother compared to the y8's sharper angle the z6 runners are BIGGER than the y8s. the y8 plenum is BIGGER than the z6. well either way swapping manifold is useless both are good till 400whp. the y8s runners are unequal length as well so in recent dynos 09-10 people have concluded that the y8 manifold causes #3 cylinder to run leaner than the rest. and over all isnt that much of an "upgrade" honda designed the manifolds to work with certain motors and head designs so stay with the same years of compatibility


so y8 advantages
* better placed fuel pressure regulator
* "bigger plenum"
* use with 96-00 only

z6 advantages
* smoother airflow
* bigger runners
* use with 88-95 civics

bigger isnt always better just put it that way

p28 is better for low end tq and throttle response

Z6
Total IM Volume 1900cc
Plenum Volume 800cc
Runner Volume 275cc
Runner length 12"


Y8
Total IM Volume 2450cc
Plenum Volume 1450cc
Cyl 1 and 4 Volume (longest runners) 275cc
Cyl 2 & 3 Volume (shortest runners) 240cc
Runner length 12"

Great info ilya !

i make compilation (in Rus.Lang) this info from DU honda tech and other http://www.ej9.ru/art/vibor-vpusknogo-kollectora-honda/

Both nice posts.

I just want to add that flow of a manifold is only a secondary issue... I believe pulsation (so length and diameter) of runners is dominant. In theory a better flowing runner can get worse results since the acoustics might be different. Still nice research.