Rember the intake port texture debates?

[Olefud]

If there was anywhere this would be beneficial a high speed ssr comes to mind. If surface texture would help the air stay attached at higher speed before separation that would make a ssr that is shape challenged perform better.

condition

If you "trip" the boundary layer to a turbulent condition-just the boundary layer- it enhances the Coanda effect, i.e. aids attachment. That's what the little projections on plane wings do. A rough texture could do much the same thing.

[KnightEngines]

Textured turns don't work, I played with that quite a bit & now go the other way - polished turns & rough everywhere else.

[Carnut1]

Just tried rough ssr vs. Highly polished ssr. Polished won.

[cgarb]

Flowbench or dyno?

[Carnut1]

Good question, bench.

[cgarb]

Would be neat to see how that works out on Chads wetflow bench. I mean we pay attention to the texture in the port and the finish dry, what does it flow like with fuel on the walls?

[mag2555]

Yup, I agree, the more velocity over the short turn , the more they had better be a nice smooth surface.

[BradH]

Textured turns don't work, I played with that quite a bit & now go the other way - polished turns & rough everywhere else.

Was this determined from flow bench and/or dyno results? And what sort of difference did you find?

[cv67]

had similar results with the polished ssr. Beginners luck maybe.

Too bad a bench couldnt simulate actual pulsing to get a better idea; what works on a bench doesnt always work in the real world huh

[John Wallace]

Maybe Larry Meaux will chime in?

He had an article in a mag that showed the dyno and/or the ET was a lot better with the textured or rough burr finish.
The flow bench never showed any better numbers. (and maybe less?)

So if racing flow benches smooth may be where it's at?

[GARY C]

Flowbench or dyno?

All the write ups I have seen on this subject says that it hurts flow but helps power. Another less talked about approach is called ribblets (comes from sail boat design)...Using a 40 grit piece of adhesive sand paper and your finger sanding in the direction of flow on any radius's.

[GARY C]

Maybe Larry Meaux will chime in?

He had an article in a mag that showed the dyno and/or the ET was a lot better with the textured or rough burr finish.
The flow bench never showed any better numbers. (and maybe less?)

So if racing flow benches smooth may be where it's at?

I think this is the article you are talking about, the texture photos are at the end. http://hotrodenginetech.com/pipemax-cre ... d-porting/

Here is the advanced thread on this. viewtopic.php?f=15&t=34837

[MadBill]

Be interesting to compare power effects on a gaseous fueled engine.

[GARY C]

Be interesting to compare power effects on a gaseous fueled engine.

The only way to know would be ABA dyno testing. Don Terrell the owner of this site wrote a NASCAR Engine book claiming ribletts were worth 10 horse, I have been told by others that that is correct but I have not tested it.
Paper on riblets for sail boats http://rsta.royalsocietypublishing.org/ ... 2.full.pdf

[cgarb]

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 thousandth of a second the valve is open and closed for turbulence to develop? This is probably a debate all to itself...