Ported Dart 215 pro1 platinum with port energy discussion

[Carnut1]

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Dart 215 Pro1 platinum. Angle milled to about 19.5 angle from 23.
These will be for a 420+ cube street mill. Dart did some nice improvements over the older non platinum design.

[Carnut1]

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Chamber shape after some 9 cuts.

[Carnut1]

dart 215 9 cfm graph.jpg

Stock vs. 9th cut 213.5 cc stock vs. 228cc 9th cut

[statsystems]

Did the flow go flat after .600 or did you just stop measuring?

[Carnut1]

Flow_Sunday_December_24_2017_14_53_31.jpg

Cfm / sq in graph

[Carnut1]

Did the flow go flat after .600 or did you just stop measuring?

.6" 311cfm, .7" 313.1cfm, .8" 313 cfm. So due to high speed ssr it is pretty flat. Thanks, Charlie

[Carnut1]

dart 215 9 port velocity graph.jpg

Port velocity graph

[Carnut1]

dart 215 9 port energy ftlbs graph.jpg

Port energy graph. Even though these ports are 228cc intake and 80cc exhaust I really worked at keeping them small and fast. Plenty of Pitot and flowball work went into these at this point. Thanks, Charlie

[Carnut1]

dart 215 9 swirl.jpg

One of the many new features is the swirl graph. Very interesting looking at the swirl progression as a port developes. I have noticed that it is possible to trade cfm for swirl. At this point I will take the cfm because there seems to be plenty of swirl! If you look at the big picture the cfm, port velocity, swirl, and port energy have ALL been kicked up. I will take it as a win. Input welcome. Thanks, Charlie

[Carnut1]

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Ssr after pic. Stock Dart ssr is very high which works for warm street application. Knocking the ssr down helps high lift and hurts low lift flow. Trying to boost the entire lift curve is a job and requires lots of cut and flow testing. This ssr is much higher than the Dart 200's I cut to 247cc. Surface texture makes a difference on this ssr as well. As the flow has increased on the top end ths ssr airspeed has exceeded 400 ft/sec and likes a polished surface to keep flow from dropping after .6" lift. Thanks, Charlie

[Carnut1]

1223171818.jpg

Bowl pic

[Carnut1]

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Unpolished ssr, much wider and lower than stock. Laid back but not radical.

[Amilcar]

Charlie, What`s the port centerline lenght of this?
Did you made any port molds of it?

[Carnut1]

5.5" and 3" no port molds. I should probably look into that. Thanks, Charlie

[pcnsd]

Charlie,
I enjoy your porting threads. I have a question on the exhaust bowl treatment in front of the valve guide (as the gas flows) See arrow on picture:
Why is this cut flat and not shaped to a divider when the bowl is opened. I don't have experience on wedge cambers but on the hemi heads I mod doing so increases low lift flow. Is the plan to limit LL flow in an effort to control reversion? Does that not also effect blow-down?

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Thanks,
Paul