Ported Dart pro 1 pre platinum

[Carnut1]

Charlie I think one of the things that will help is to have a long sweeping radius on the roof starting off at Just before the the valve guide pops thru the roof, with the tallest at the short turn crown and then dropping back down at the flange .

I did not read all the way thru this string of post so I need to ask, what is your throat percentage at?

Are you flow gain percentages so far greater then your port volume percentage increase?

Yes DV said the same thing I remember some graphics in one of his slides also promoting velocity on the common wall side

I feel I am on the other side of that curve already. That is one reason I have not cut it for the larger gasket size. On this port the common wall is slower than the pushrod wall. I did get good gains on the pushrod wall in earlier testing. The straight wall is already pushed right into the bolt boss. Thanks, Charlie

[JoePorting]

I'd cut the intake side to a fel-pro 1206 gasket. Raising the roof of the port is always a good thing.

[Carnut1]

I'd cut the intake side to a fel-pro 1206 gasket. Raising the roof of the port is always a good thing.

Thanks, I appreciate your input. Charlie

[Carnut1]

I should add that airspeed on the floor is high and airspeed on the roof is not so high. I would think raising the roof may make this worse.

[jcisworthy]

Did you measure the CSA throughout the runner? How is it sized?

Pinch was 2.354 " - radius. The ssr is 3.026" - radius. Thanks, Charlie

I meant starting at the entrance and every 1/2" to the seat to see how the runner is sized throughout.

[MadBill]

Make a lot of patterns, trace them onto 1/4" square-lined paper and go blind counting squares, or use poster cardboard and weigh the slices on a good sensitive scale.

[Carnut1]

Did you measure the CSA throughout the runner? How is it sized?

Pinch was 2.354 " - radius. The ssr is 3.026" - radius. Thanks, Charlie

I meant starting at the entrance and every 1/2" to the seat to see how the runner is sized throughout.

I have not mapped this port. I have been thinking of mapping them with Pitot air speeds. Thanks, Charlie

[mhr144]

viewtopic.php?f=1&t=4244

[Biteme]

Here's a tracing of the ssr in my dart pro1's.
They started out as 180cc, now are around 210.
Biggest place I found for gain was pushrod pinch. Opening it 0.060 gained me .3 sec on dragstrip.
I've since opened prp up to 2.25", raised roof about 0.080, lessened the guide boss and taken a very minimal skim off the ssr to tidy up some bumps that were on them.
All these extra things have only gained me about 0.1 sec.
I'm thinking there might be power in laying back the ssr but I'm not sure.
They're flowing at around 280 at moment.

[JoePorting]

Lowering the floor to .900" should help.

[Carnut1]

Lowering the floor to .900" should help.

I think I am at about .925" but I feel it needs a bit more cutting. Thanks, Charlie

[randy331]

I was given a very simple job on these heads. Have them beat a cnc head!

Beat a cnc head how?
On the flow bench?
On the dyno?

How will you decide they are/aren't beating a cnc head?
What criteria will be used to determine that?

Randy

[zums]

Lowering the floor to .900" should help.

I think I am at about .925" but I feel it needs a bit more cutting. Thanks, Charlie

whats the average csa/ fps of the port
Tom

[Strange Magic]

Biggest place I found for gain was pushrod pinch. Opening it 0.060 gained me .3 sec on dragstrip.

You backed the pushrod pinch area off by .060 and picked up 55 to 60HP? That's quite a bit of a power gain for just working .060 off the pushrod pinch area.

[Biteme]

Biggest place I found for gain was pushrod pinch. Opening it 0.060 gained me .3 sec on dragstrip.

You backed the pushrod pinch area off by .060 and picked up 55 to 60HP? That's quite a bit of a power gain for just working .060 off the pushrod pinch area.

11.30 to 10.96
No other changes.