Dimpled... carburetor... venturi...

[BradH]

I remember seeing pics of CNC venturi mods that AED displayed at PRI a couple(?) years ago, but hadn't heard about it since. I checked out their FB page yesterday and saw they posted pics of a Circle Track 4150 that had them. Haven't heard what their claimed benefits are, but IMO it adds another twist on the never-ending induction runner surface debate.

[ClassAct]

I saw that on FB too. It's interesting for sure. I have never been successful with surface variations like Chad Spier and the guy who does the computer program I can't think of now. Damn memory.

It would take some serious testing to either validate or disprove the dimples by my first thought is you are going to increase exit loss if you ain't careful.

[PRH]

At least A-B testing carbs is way easier than cylinder heads and intake manifolds.

[BradH]

My question is whether the peak airspeed in a carb venturi is enough to thin the boundary layer increase that results from the surface modification. If so, you MIGHT be able to modify a "large" venturi to act like a smaller one at lower airspeed, and "open up" at higher airspeed to flow more like the actual venturi size.

Here's one of the pics AED posted on their FB page.
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54415264_1396138870561399_360773584961929216_o.jpg

[pamotorman]

remember when bill Elliot was killing them in NASCAR they said it was dimpled piston tops and combustion chambers but it turned out to be the thunder bird body was just more aero friendly so GM brought out the lumina.

[Kevin Johnson]

Maybe part of the desired effect is to induce a swirl.

[Carnut1]

My question is whether the peak airspeed in a carb venturi is enough to thin the boundary layer increase that results from the surface modification. If so, you MIGHT be able to modify a "large" venturi to act like a smaller one at lower airspeed, and "open up" at higher airspeed to flow more like the actual venturi size.

Here's one of the pics AED posted on their FB page.
.
54415264_1396138870561399_360773584961929216_o.jpg

I think you make a good point, think of it a a variable sized venturi. As the air speed is slow the turbulent layer is thicker and as air speeds up it thins. Thanks, Charlie

[BOOT]

It's an E85 carb, so higher volume of fuel and it may be more of a mixture aid sim to burr finish.