Anyone ever tired this ? Does it actually work ? What were the flow numbers before and after ? TIA

That would have taken some time to program !!!

Saw this on some Glidden stuff way back. Piston domes too.

Simular to golfball airflow techknowlogy?

The term snake oil can be inserted here.....Its been around for a couple decades now

Builds up the boundary layer, makes the port "smaller" is my take.

Just wondering is all, there was quite a debate on faceache with both sides of the argument but no conclusive proof either way. Seems like the import guys are the majority of the "yays".
My take is if it did work, it would be available as an CNC option on every decent cylinder head available.

The late Jim McFarland was a proponent of this. I respected Mr. McFarland a lot but there sure has not been wide spread adoption of the dimples.

Mythbusters did something like this on a whole car and I think in their opinion he made the car more aerodynamic.

Dimples, riblets ("shark skin"), burr finish... all forms of port surface finishing that some have claimed show improvements and others have doubted vociferously

You decide....

Interesting...the prior reading I've done on this topic was focused on preventing the fuel, once it began falling out from the air stream from actually settling down on the port walls. Idea here being that those vortices would 'shake' the droplets back up into the airstream before they ever got a chance to come in contact with the port wall.

Ultimately the goal there was to keep the fuel in suspension and therefore make more of it available for efficient burn in the chamber, thus producing more power.

Good point, flow numbers may not tell the whole story. I'm guessing no-one has any non-dimpled v's dimpled dyno numbers or track results ?

I am not sure if Larry Widmer’s forum posts are still on the web, but he did a much better job of describing how a small number of exactly spaced dimples can improve airflow.

Larry Widmer’s dad was an aerodynamic engineer justly famous for his contributions to the F-16 design.

This article describes how a dimple just past mid chord on the upper side of a wing improves flow.

http://www.journals.theired.org/assets/pdf/20151019_064614.pdf

Why do golf balls benefit from all around dimples?

A round ball is a terrible, terrible, terrible shape for an airplane wing.

Dimples all around make the golf ball a slightly less terrible wing shape - but only if the spin of the golf ball is correct to create up lift.

If the spin is wrong the dimples actually make the golf ball go right, left, or “down lift” into the grass faster.

Bumps most times work better than dimples.

Bird wings have bumps and notches rather than dimples.

A moving ball is different than the stationary walls of a port. Increasing the boundary layer speeds up the velocity keeping the fuel suspended. Fuel drops out at a slowdown point. At least by my thinking.

Let me try again SNAKE OIL.....

which is why I find it interesting that BES offers (offered?) the dimpling as an add-on upgrade for certain CNC programs

Yep.....

I can guarantee you if there was something there EVERY Comp car and PS team out there would be doing it. We work with one of the most prominent head porters in the country on our stuff and he does a LOT of comp stuff. He said they tried it years ago and it was worth nothing. I tend to believe him more than the internets. Having spent alot of time around top comp teams and very good friends with a person who has built some of the fastest comp stuff out there I can tell you without a doubt its not used by the top teams.

I would not be surprised that BES offers it. Possibly to appease those who insist. We race with alot of folks who run BES stuff and none of them use it

Not surprised... at all

Even Chad Speier as a big proponent of the burr finish technique has stated it's not always appropriate for the application; I think that applies pretty much to all of this stuff

"Builds up the boundary layer, makes the port "smaller" is my take."

No. The principle is the same as "vortex generators", the point being to keep airflow against the surfaces - ideally making use of the full port volume, not decreasing it.