As you guys know Teflon coating such as found on pans is not especially smooth; It is pretty comparable to cast finish. This and the low friction coefficient might have more benefit than at first glance. I read an SAE paper recently where GM found that Teflon coating their TB's increased airflow 28% at part throttle... A number I have a hard time believing but Admittedly TB's and plates are not "rough" to begin with so the Teflon may have improved the finish with respect to boundary layer. (made it rougher). Paper is here, Teflon coating reference is buried:
http://www.kettering.edu/~lpgvan/SAE-LPG.html

Practically speaking, Exhaust ports carbon up and tend to cake smooth after some use, and Intake ports tend to get coated with varnish/gum, even dry intakes tend to get a greasy coating in the last third of the runners from reversion, and the entire tract from the plenum inward with trace oils from PCV.

So an exhaust ports reynolds number is changed from rough cast finish to being smoother than cast, for most of an engines effective life span. The carbon we have all seen is about the texture of flat black paint. The carbon can build up and impede flow. Mirror polishing an exhaust port would give the carbon less to hold onto. I don't know if Teflon would be able to stand up to the sustained temps. Then again I believe the coating process happens at ungodly high temps and pressures. On the other hand carbon has a very low CF so if it doesn't build up too thick it may actually help flow.

Now Intake ports with built up gum and varnish ... well that stuff is like glue to the touch and at the same time greasy smooth in texture. It takes considerably longer to start building up in a dry intake, but if the engine happens to have more reversion into the intake ports, oil can build up rather quickly. And if it's a wet intake... Well...

Teflon coating might help keep things clean for longevity and keeping runners flowing optimally... Especially if that gummy stuff promotes a poor boundary layer, which if polishing promotes a poor boundary layer then smooth oily looking goo must as well)

Where Teflon could help performance wise is velocity, if Intake ports/runners are a balance between 'high end' high volume air flow and 'low end' air velocity.

If we can assume that Teflon's texture is sufficient to promote a 'good' boundary layer. Shouldn't the lower friction coefficient increase port velocity? I'm getting a hunch this question is all wrapped up in the boundary layer effect. Which is obviously over my head.

I'm not an engineer but I like studying new theories. What do you guys/gals think?

 

Teflon is a registered trademark of the Dupont corporation and is used here without permission. You can tell I'm serious because I signed up on the forum for the sole purpose of telling you this.

 

Interesting theory. but wouldn't a teflon surface be guilty of that same smooth boundary layer also?

 

VGPowah, Jeff.

 

Sue Me. now back to the question.

 

I think any benefits would be negligible (sp?). Otherwise, Teflon Ž would have been utilized for this application some time ago.

 

The throttle plate was also profiled, which may have had a greater effect on the air flow than the coating. I don't believe they tested each individual modification seperately, so it is hard to determine which one played a more significant role

 

Let me guess..... You work for Dupont????

 

No he's just a big goober. He's harmless.

 

he's a *******

 

he's a large cardboard box?

 

That is an interesting idea tho