D-series cylinder head flow charts?
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From: Ancaster, Ontario, Canada
D-series cylinder head flow charts?
I'm looking for flow bench charts for D16z and D16y8 heads. Anybody know what these heads flow in stock form?
If you're wondering what I'm talking about, have a look at the charts on the Alaniz Technologies website...
http://www.alaniztechnologies.com/flowcharts.html
I'm looking for these charts, but for D-series engines. Anybody know if this info is out there in cyberspace somewhere? I just did a DIY porting of a Y8 head and I'm going to have it blow benched but I'd like to know what some baseline numbers are so I can determine if the headwork was benefitial.
Thanks for any info you can provide,
Dave
If you're wondering what I'm talking about, have a look at the charts on the Alaniz Technologies website...
http://www.alaniztechnologies.com/flowcharts.html
I'm looking for these charts, but for D-series engines. Anybody know if this info is out there in cyberspace somewhere? I just did a DIY porting of a Y8 head and I'm going to have it blow benched but I'd like to know what some baseline numbers are so I can determine if the headwork was benefitial.
Thanks for any info you can provide,
Dave
Thread Starter
Junior Member
Joined: Jan 2001
Posts: 333
Likes: 0
From: Ancaster, Ontario, Canada
Re: D-series cylinder head flow charts? (JaeOne3345)
never used IM...but feel free to drop me an e-mail at dpratte4@cogeco.ca if you want. Below are a few notes picked up from various sources. There's also an excellent article published in Grassroots Motorsport magazine in the September 2002 issue that covers a lot of the basics in a very clear manner.
On D-series Head Porting – Bisimoto (first 11 and 10 second 1/4 mile naturally aspirated D-series)
whether a full blown n/a race engine or a tame street vehicle, it is wise to only mildly port the head. Mostly clean up the bowls and casting ridges. Definitely never take material from the port floor: this kills performance by decreasing port velocity. Even though a common practice, polishing the head should be avoided as well. The intake ports should be kept slightly rough (vertical ridges preferred), in order to keep the fuel in suspension, and not allow it to stick to the port walls. It does not really matter if you polish the exhaust...it will get coated with combustion by products anyway.
Note: I keep racing d-series motors because they are relatively inexpensive to build compared to b-series: I hate spending money, and I desire to be fast!
For a beginner it is a good idea to stay away from the valve seats and valve guides.
On Y8 Head Porting – various thread at dseries.org
The y8 head has one of the intake ports on each cylinder partially obstructed to aim the output towards the center of the cylinder. This is to create strong swirl in the combustion chamber. This is an emmisions and fuel economy measure. There is already strong swirl induced by the inequality in the primary intake lobes and the head will flow a lot better by matching the bad port to the good one in contour. Zex man's 400 hp turbo motor lost 20 hp with the y8 head compared to the z6 due to this trait. It's easy to fix though, as you have the other port to use as a guide. The y8 head has a better combustion chamber design than the z6, as well as a more aggressive cam. Once you fix the obstructed intake ports it is superior in every way.
I didn't take pics of the head I worked on, probably should have. To be honest it shocked me, I took the head apart to do the valves and it was obvious the right intake port (when viewed from the gasket surface) on each cylinder is downsized and aimed. Swirl is definately a good thing, but the primary intake lobes are already unequal for this reason. d16z6's don't have this downsized port, and still have perfectly adequate swirl. It might be important if your trying to achieve ULEV status without a 3 way catalyst but it doesn't translate to usable power.
Matching the small port to the size and contour of the good one is definitely recommended. I am currently running the chamber untouched, as I only have 10:1 CR of the z6 pistons. Once I get a motor built with a6 pistons I'll de-shroud the valves a little bit too. 11.4:1 (or a little less after cleaning up the chambers) with a fixed y8 head with stock y8 cam, and a header makes decent power. I use the y8 manifold and a 60mm b motor TB.
As I recall it was the port on the right that is slanted towards swirl when viewing from the bottom, making it the further one from the cam pulley.
Unfortunately I didn't take many pictures during the porting, I was having too much fun! But I will take some pictures of the final product and post them up here with some commentary on where we worked on it if you'd like.
Hope this helps,
Dave
On D-series Head Porting – Bisimoto (first 11 and 10 second 1/4 mile naturally aspirated D-series)
whether a full blown n/a race engine or a tame street vehicle, it is wise to only mildly port the head. Mostly clean up the bowls and casting ridges. Definitely never take material from the port floor: this kills performance by decreasing port velocity. Even though a common practice, polishing the head should be avoided as well. The intake ports should be kept slightly rough (vertical ridges preferred), in order to keep the fuel in suspension, and not allow it to stick to the port walls. It does not really matter if you polish the exhaust...it will get coated with combustion by products anyway.
Note: I keep racing d-series motors because they are relatively inexpensive to build compared to b-series: I hate spending money, and I desire to be fast!
For a beginner it is a good idea to stay away from the valve seats and valve guides.
On Y8 Head Porting – various thread at dseries.org
The y8 head has one of the intake ports on each cylinder partially obstructed to aim the output towards the center of the cylinder. This is to create strong swirl in the combustion chamber. This is an emmisions and fuel economy measure. There is already strong swirl induced by the inequality in the primary intake lobes and the head will flow a lot better by matching the bad port to the good one in contour. Zex man's 400 hp turbo motor lost 20 hp with the y8 head compared to the z6 due to this trait. It's easy to fix though, as you have the other port to use as a guide. The y8 head has a better combustion chamber design than the z6, as well as a more aggressive cam. Once you fix the obstructed intake ports it is superior in every way.
I didn't take pics of the head I worked on, probably should have. To be honest it shocked me, I took the head apart to do the valves and it was obvious the right intake port (when viewed from the gasket surface) on each cylinder is downsized and aimed. Swirl is definately a good thing, but the primary intake lobes are already unequal for this reason. d16z6's don't have this downsized port, and still have perfectly adequate swirl. It might be important if your trying to achieve ULEV status without a 3 way catalyst but it doesn't translate to usable power.
Matching the small port to the size and contour of the good one is definitely recommended. I am currently running the chamber untouched, as I only have 10:1 CR of the z6 pistons. Once I get a motor built with a6 pistons I'll de-shroud the valves a little bit too. 11.4:1 (or a little less after cleaning up the chambers) with a fixed y8 head with stock y8 cam, and a header makes decent power. I use the y8 manifold and a 60mm b motor TB.
As I recall it was the port on the right that is slanted towards swirl when viewing from the bottom, making it the further one from the cam pulley.
Unfortunately I didn't take many pictures during the porting, I was having too much fun! But I will take some pictures of the final product and post them up here with some commentary on where we worked on it if you'd like.
Hope this helps,
Dave
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