Rember the intake port texture debates?

[GARY C]

As I understand the port texture and riblet technique is not about flow but getting the air to follow the port and atomizing fuel.

[cjperformance]

I have to question the little " tricks" people do to get the last little bit of flow. If a port is sized correctly, and has a good shape to it if you cut a little bit here and gain 5 cfm or use a super trick valve job to gain flow, has there been back to back dyno tests to prove that equates into real gain? I guess nascar and prostock is the proving grounds for this were a couple hundredths of et or tenths of a mph matter. Not just surface finish but like adding a wing in a port to get rid of turbulence, Is there enough time in a thousanth of a second the valve is open and closed for turbulence to develop? This is probably a debate all to itself...

Given the conditions inside an intake manifold while the said valve is closed,, I would say turbulence is a given, a good port then controls the inherent turbulence and stabilises flow 'very' quickly to equate to good real world port flow and cylinder fill.

[cv67]

x2cgarb doubt most of em at the ground makes no or litte difference if any

[user-9274568]

If I put a floor wing in a port, it's not for turbulence.. just sayin.

A good port shape take care of that.

[cgarb]

Not knocking your port wings Chad...just a quick example that came to mind when I was thinking about small port features. I'm sure you tested your ports with and without the wings on the bench, if you wouldn't mind how much cfm's was the wing worth?

[cv67]

do those goofy airstream helmets make bicyclists go any faster as they are more aerodynamic than a head ..

lol j/k guys keep it coming .

[GARY C]

do those goofy airstream helmets make bicyclists go any faster as they are more aerodynamic than a head ..

lol j/k guys keep it coming .

I think those are to keep weak necked bikers from looking like bobble heads...Just saying.

[cjperformance]

do those goofy airstream helmets make bicyclists go any faster as they are more aerodynamic than a head ..

lol j/k guys keep it coming .

I think those are to keep weak necked bikers from looking like bobble heads...Just saying.

Naaaa, its cos they look good !

[n2xlr8n]

The fuel puddling is seen very easily in EFI systems with datalogging. In fact, the best systems use OEM-style "wall-wetting" transient algorithms to account for the dynamic conditions that affect addition to and subtraction from the "puddle."

Could you expound on this a bit? PM if necessary.

[n2xlr8n]

As I understand the port texture and riblet technique is not about flow but getting the air to follow the port and atomizing fuel.

That is my understanding as well, but would one not see the "air following the port" on a bench?

[BOOT]

I still think it's simple as surface area to help thin the fuel out on the surface. Those round dimples would maybe promote balls/balling/pools with some fluids at low air speeds. idk maybe dimples or even texture itself contains excess fuel at low rpm until needed at higher rpm or sorta helps the transition.

[BradH]

As I understand the port texture and riblet technique is not about flow but getting the air to follow the port and atomizing fuel.

That is my understanding as well, but would one not see the "air following the port" on a bench?

On two of three heads I applied "riblets" to on the SSR, both picked up about 5 cfm above .500" lift when flow-tested up to .700". One was a mid 9-sec. bracket car and the other was a mid 10-sec. street/strip car.

The third head I tried them on showed no improvement... even seemed to be a small step backwards for some unknown reason. Never ended up trying those heads out myself, unfortunately, and now I'm contemplating whether I want to apply them to the heads going on my current (re)build.

It would really be interesting to see what they'd show on wet-flow bench. The whole short-turn surface texture question has been bouncing around in my semi-hollow head for years, which is why I tried "riblets" after buying Don T's books that talked about them.

[BOOT]

Just occurred me to dimples/burr finish is about holding fuel or wetting the walls better for the cooling effect. Increased surface area w/o the downside of smooth wetting.

[lefty o]

Just occurred me to dimples/burr finish is about holding fuel or wetting the walls better for the cooling effect. Increased surface area w/o the downside of smooth wetting.

its like a golf ball, its the boundary layer of air thing.

[BOOT]

No it's not, that is for objects that can't be streamlined like a wing.

edit: for trailing air on non streamlined objects