Novice Modified 289 Heads

[mag2555]

Sounds good David, and thanks!
I hope your recovery is progressing with God speed!

[The Iron Icon]

I think this is what some of you have been waiting for.
From the chamber shot you can see I have a ways to go before my work looks as pretty as Charlies but hey i'm still a youngster at 25!!

More to the point is the flow bench curves. The ports went up in cc's from whatever stock is -(???) to what is still a small port at 159 cc int and 50 for the ex.
Intake flow went up from 160 to 201 E3x from 126 to 160. This was done by increasing the efficiency a greater amount than the port volumes so port velocity also went up bu a big margin. This cause the all important port energy to go up by a very big margin. DV tells me this will all show up in a positive manner in the dyno test.
Last point and DV said to stress this. The port work we are looking at here is what DV calls a safe port for a 289 head.

On the graphs thin lines are stock, thick are ported.

Phil

[Carnut1]

You are a lucky kid Phil. Looking good.

[The Iron Icon]

Thanks Charlie, Happy to have all of these opportunitys. First time using the flow bench to see how ports responded, me and DV are pretty happy with the results straight from just porting. And i should add that before the tests we did check calibration of the flow bench and it was within .5cfm .

[Carnut1]

I have calibrated that bench a few times. Each time it was very close, D.V. likes it tight.

[mag2555]

I must admit here that I am having a hard time swallowing a 25.6% peak Intake flow gain from just bowl porting work on this one!

Can you atleast tell us what the Valve to Throat percentage is now ?
Can you go into detail on what some sizes where stock and what they are now if you can?

Also why are the Valve lift numbers being given in those increments used in the charts?

[RevTheory]

That's some pretty wild mean velocity, bud. Have you probed it for local velocities yet?

[gmrocket]

I must admit here that I am having a hard time swallowing a 25.6% peak Intake flow gain from just bowl porting work on this one!

Can you atleast tell us what the Valve to Throat percentage is now ?
Can you go into detail on what some sizes where stock and what they are now if you can?

Also why are the Valve lift numbers being given in those increments used in the charts?

I was wondering the same,,vertical axis is in 21 cfm increments and horizontal in .070" lift.

You'll have to extrapolate both if your trying to follow along with the same type head.

[Stan Weiss]

I must admit here that I am having a hard time swallowing a 25.6% peak Intake flow gain from just bowl porting work on this one!

Can you atleast tell us what the Valve to Throat percentage is now ?
Can you go into detail on what some sizes where stock and what they are now if you can?

Also why are the Valve lift numbers being given in those increments used in the charts?

The program took the max valve lift and produces 10 evenly spaced lines.

The program also takes the lift points / flow data and generates a "spline curve" which it graphs, rather than straight lines from data point to data point.

Stan

[Stan Weiss]

David / Phil,
Is the your exhaust valve size the same size for both tests?. There is a thick and thin horizontal red line which shows at .25 D for the exhaust valve. Note the blue lines overlap each other .25 d intake.

Stan

[mag2555]

So where going back to the .25LD way of looking at things to compair Valve efficiency on this ?

[Stan Weiss]

So where going back to the .25LD way of looking at things to compair Valve efficiency on this ?

No. The .25 D lines are an option which by default is set to show. If you un-check a box it does not show the .25 d lines. Different people like to look at the data differently. That is why the x axis can be L/D ratio instead of valve lift. You know some like vanilla and some like chocolate.

Stan

compare.gif

[gmrocket]

I must admit here that I am having a hard time swallowing a 25.6% peak Intake flow gain from just bowl porting work on this one!

Can you atleast tell us what the Valve to Throat percentage is now ?
Can you go into detail on what some sizes where stock and what they are now if you can?

Also why are the Valve lift numbers being given in those increments used in the charts?

The program took the max valve lift and produces 10 evenly spaced lines.

The program also takes the lift points / flow data and generates a "spline curve" which it graphs, rather than straight lines from data point to data point.

Stan

Why does it need a max valve lift? Does that mean if you change the max valve lift by .025" up or down, both H&V axis will have different values again for this same head?

If it will, us who are only seeing a graph here will have a hard time comparing things.

I have a head with the same size intake valve I'm trying to compare with this one...i thought it would be easy.

[The Iron Icon]

David / Phil,
Is the your exhaust valve size the same size for both tests?. There is a thick and thin horizontal red line which shows at .25 D for the exhaust valve. Note the blue lines overlap each other .25 d intake.

Stan

Stock valves were used for both tests, i believe we actually used same exact ones.

[Stan Weiss]

I must admit here that I am having a hard time swallowing a 25.6% peak Intake flow gain from just bowl porting work on this one!

Can you atleast tell us what the Valve to Throat percentage is now ?
Can you go into detail on what some sizes where stock and what they are now if you can?

Also why are the Valve lift numbers being given in those increments used in the charts?

The program took the max valve lift and produces 10 evenly spaced lines.

The program also takes the lift points / flow data and generates a "spline curve" which it graphs, rather than straight lines from data point to data point.

Stan

Why does it need a max valve lift? Does that mean if you change the max valve lift by .025" up or down, both H&V axis will have different values again for this same head?

If it will, us who are only seeing a graph here will have a hard time comparing things.

I have a head with the same size intake valve I'm trying to compare with this one...i thought it would be easy.

Yes. The graph axis will change. The text part of that screen shows the actual numbers.

Stan

comp_text.gif