Comparing Y8 IM volumes to Z6 IM volumes

Moose · Sep 25, 2003

I was At Maxzee's tonight working on his car with him, and afterwards we decided to compare the Z6 and Y8 Intake manifolds he has sitting in the basement.

We know the Y8 Intake Manifold is bigger than the Z6 Intake manifold, but by how much ...nobody really knows so we figured we would measure what the internal volumes are.

Using a VERY scientific and accurate measuring techinique ... NOT !!!! ... we measured the runner volumes and plenum volumes of both the Y8 and Z6 by sealing the various openings with duct tape, and filling the runners and the plenum with water and then measuring (using a standard kitchen measuring cup) the amount of water first in the entire IM and then just the runners, thus by simple subtraction we can also deduce the Plenum volume

This is what we found. Keep in mind that the numbers are not particularily accurate, but they are intersting none the less.

Z6
Total IM Volume 1900cc
Plenum Volume 800cc
Cyl 1 and 4 Volume (longest runners) 275cc
Cyl 2 & 3 Volume (shortest runnners) 275cc

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

So the Y8 is 25% larger overall, has 45% more plenum volume, and has mis-matched runner volumes with the inner runners having 15% less volume than the outer runners, and its outer runners are the same volume as the Z6.

What this all means in power gains is a bit of a guessing game, but some prior dynopulls I did show a loss in power below 4000 rpm bump in the power between 4500 and 5500 rpm and a general increase in power from about 6000 to fuel cut which I atribute to the Y8 IM.

So there ya go

Cheers

Moose

DOHCDX · Sep 25, 2003

great info, now, someone with a skunk2 do the same and post your results

seano · Sep 25, 2003

DOHCDX said:
great info, now, someone with a skunk2 do the same and post your results

Yes, and a Edelbrock. That would be lovely.

Guest · Sep 26, 2003

do you think it would be a good idea to put the y8 manifold on the z6 head?

zeus zore · Sep 28, 2003

sqmark said:
One for the Archive maybe :?:

Good info mate

yeah !! archive !!

but HOW much did you gain in the top end !? 2 HP ?! efter 6K RPM !? over the Z6 ?

DOG · Sep 28, 2003

Any specs on the D15b7 intake? same specs as the z6? You can pic b7 IM up for cheap and if they are the same (besides the injectors and throttle body) then it would be a great alternative for the price.
Great post!

zeus zore · Sep 28, 2003

Hondadog said:
Any specs on the D15b7 intake? same specs as the z6? You can pic b7 IM up for cheap and if they are the same (besides the injectors and throttle body) then it would be a great alternative for the price.
Great post!

what car is that in year ??
enigne spec ? 114 hp ? or 90 ? vtec e ?

DOG · Sep 28, 2003

92-95 Civic DX
92-95 Civic LX

Non-vtec

D15B7 1493cc

4 cyl, 16 valve SOHC

9.2:1 c.r.

PGM-FI (MPFI)

102 bhp @ 5900

98 lb-ft @ 5000

Redline: 6800 rpm98 lb-ft @ 5000

zeus zore · Sep 28, 2003

i dont think we have the motor here !? do you have a pic of one ??
we have a D15Z1 i think with a look alike Y8 intake manifold !? think thats it ? but thats a 114 HP vtec-e

DOG · Sep 28, 2003

no its not the z1. Im not sure which DTM version the b7 would be. Its not vtec or vtec-e .Its just a 16v non-vtec.

Skar · Mar 2, 2011

Moose said:
I was At Maxzee's tonight working on his car with him, and afterwards we decided to compare the Z6 and Y8 Intake manifolds he has sitting in the basement.

We know the Y8 Intake Manifold is bigger than the Z6 Intake manifold, but by how much ...nobody really knows so we figured we would measure what the internal volumes are.

Using a VERY scientific and accurate measuring techinique ... NOT !!!! ... we measured the runner volumes and plenum volumes of both the Y8 and Z6 by sealing the various openings with duct tape, and filling the runners and the plenum with water and then measuring (using a standard kitchen measuring cup) the amount of water first in the entire IM and then just the runners, thus by simple subtraction we can also deduce the Plenum volume

This is what we found. Keep in mind that the numbers are not particularily accurate, but they are intersting none the less.

Z6
Total IM Volume 1900cc
Plenum Volume 800cc
Cyl 1 and 4 Volume (longest runners) 275cc
Cyl 2 & 3 Volume (shortest runnners) 275cc

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

So the Y8 is 25% larger overall, has 45% more plenum volume, and has mis-matched runner volumes with the inner runners having 15% less volume than the outer runners, and its outer runners are the same volume as the Z6.

What this all means in power gains is a bit of a guessing game, but some prior dynopulls I did show a loss in power below 4000 rpm bump in the power between 4500 and 5500 rpm and a general increase in power from about 6000 to fuel cut which I atribute to the Y8 IM.

So there ya go

Cheers

Moose

brilliant info, im just curious tho as to what the loss in power was caused by? could it have been by the 240cc runners being slightly too small? what if one where to machine the slightly bigger(say 250, 255) or even make them the same size as the outer runners(275cc).

if the cuase ofthe loss below 4k rpm was attributed to the to the above, hen as said in the above would increasing the smaller runner capaticy possibly elimate it?

im new to this forum, im on a South African Based forum as i live in that county and i owd a DOHC, but i used to have a old d15z4 so yea, interested. sorry for the thread revival after all this time - this is the first i have seen of it

99EJ6T · Mar 2, 2011

wow.. 8 year old thread huh? nice grave digging.. :lol:

your questions can be answered with further research into how an engine "inhales" at certain rpm.

transzex · Mar 2, 2011

99EJ6T said:
wow.. 8 year old thread huh? nice grave digging.. :lol:

your questions can be answered with further research into how an engine "inhales" at certain rpm.

Be nice!

His post only proves some folks can use the search function properly.

I'll even bet he is a friend/buddy of flatfourfun who is also in South Africa.

ddd4114 · Mar 2, 2011

Considering this gets asked at least a handful of times each month, I really have no problem with this thread being resurrected.

loki_ · Mar 2, 2011

on a vitara build, if i had to choose between a y8 and a z6, which one should I go with? The uneven runner length concerns me about leaning out cylinders on the y8 manifold.

Skar · Mar 2, 2011

transzex said:
Be nice!

His post only proves some folks can use the search function properly.

I'll even bet he is a friend/buddy of flatfourfun who is also in South Africa.

correct. i know FFF and am on the same forum as him. surpised people commented lol didnt think any1 would care haha. but ill search the "how an engine inhales at certain rpm and see what i can find, i only hope that i can understand it in terms of these two manifolds as i presume the post/thread/s will not be about y8 and z6 manifolds.

nice forum u guys got here btw guys.

40MPGd15b7 · Jan 18, 2012

so does the z6 intake manifold produce more power to the y8 on the b7 at below 4000 rpms? and if so theres not much point IMO? first gear is pretty low it revs up pretty quickly gets to 4 grand easily..and when you red line it in first shift to second with the cx/dx tranny your at 4000-4500 rpm in 2nd already.. just a thought..

transzex · Jan 18, 2012

I covered years ago.....

TheToaster · Jan 18, 2012

Y'all like the GE mani around here? Would be interested in the specs.... Off to the search page!

buzzbomb · Jan 18, 2012

TheToaster said:
Y'all like the GE mani around here? Would be interested in the specs.... Off to the search page!

i hear the str manifold is really really good...
SAVE on STR Intake Manifold - RacingWorks.com - STR Intake Manifold B16 Civic K20 RSX Civic Si Prelude H22

Comparing Y8 IM volumes to Z6 IM volumes

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