www.dodo-upgrades.nl

Brilliant info!

I've got more flow charts of the Z6 head and the Y8 head.Be aware that these flow numbers are from a different flow bench.So don't compare them to the y7 flow numbers from the first page.It's like using dyno's to test your cars hp ,they don't all read the same.

Flow charts came from ASP( Advanced Street Performance)


Stock VS fully ported D16Z6 head


Stock VS fully ported D16y8 head

You can clearly see the Y8 gains more flow in the Low to mid range lift and the Z6 gains more in high lifts.This is cause of the more straight shaped Z6 intake ports and the twisted /curved Y8 intake ports.


To make things more clear i've found some pictures



D16y8 intake ports ,look at the misaligned/ curved divider .


Another view of the D16y8 intake ports,you can see how the ports make a curve

These are D16z6 intake ports ,you can see how these are more straightend and open


And another view of the Assymetrical intake ports of the D16y8 head.

Great pics nick, so standard the Z6 head flows better than the Y8. ood to see some evidence to back this up. Although its qute clear to see that after the porting was done both heads flowed pretty much the same, which is good for me as I have a Y8 head

50Cfm difference between ported and unported ! Impressive... so, we must have a good work done at the head, for having a good velocity to flow ratio !

Law_ wrote:50Cfm difference between ported and unported ! Impressive... so, we must have a good work done at the head, for having a good velocity to flow ratio !

Yes but this is the limit on stock valve size , these both were stage 4 port jobs and a gain of 30 CFM is allready a lot .Don't stare blind on those high numbers guys , you need to look at how much lift your cam has.

This y8 head for example makes 207CFM at 0.5" of valve lift .Your average aftermarket cam doesn't have that much lift at all.So you'll not even get to using that 207Cfm.My Bisimoto stage 2 cam for the D14a4 has aprox. 0.35" of lift max ,vtec cams generally have more lift then non-vtec cams.

So, after this figures, you do reccomend the y8 head for a mini me over a z6 head?

and another reason why the vtec cam will make more power difference than a non vtec right?

saxophonias wrote:and another reason why the vtec cam will make more power difference than a non vtec right?

No not really ,the vtec cam doesn't make more power it just has a broader power band.A well developped non vtec cam makes the same peak power as a vtec cam.De non-vtec cam works best in the mid to high revs.Vtec works well in low to mid and mid to high because of the vtec offcourse.

If we are talking about putting vtec cams onto D14 engines i don't recomend using any D16 vtec cams.Like i said before a D16 bottem end isn't the same as a D14 bottem end so they both need different cam specs.You got a difference of 200cc , 1 engine that come's alive in higher revs (d14) and 1 engine that likes the lower to midrange revs. (d16)

Well atleast these are my thoughts on vtec vs non vtec cams.

I know this is a really old thread and I am sorry for bumping it.

I was hoping someone saved the flow data pictures of the Z6 and Y8 heads as it shows critical data for stock and ported which is not easily obtainable for formula use.

The head pictures are there but the flow data is not. Did anyone by chance save that information?

TomCat39 wrote:I know this is a really old thread and I am sorry for bumping it.

I was hoping someone saved the flow data pictures of the Z6 and Y8 heads as it shows critical data for stock and ported which is not easily obtainable for formula use.

The head pictures are there but the flow data is not. Did anyone by chance save that information?

I had a look on my external hard drive but i couldn't find those pictures.I had copied the links from the OneCam Only website but that site is down and doesn't work properly anymore. I know the stock Y8 and Y7 or D14 head flows the same .The Z6 head flows a little bit better but has larger ports .The Reason why the Y8 or Z6 head makes more hp is more because of the better camshaft . If you Really want to see those pictures again you could ask ASP (Advanced Street Performance) They posted those pictures on the OneCamOnly website. http://advancedstreetperformance.com/