Vane on floor of port

[andyf]

Anyone have a good explanation for what the vane on port floor does? I have a couple of ideas but I'm not sure exactly why a port designer would use a vane. One thought I had was that the vane fills in a low velocity area so you reduce the port size without losing any flow. The other thought is that the vane helps the airflow turn the corner somehow. Maybe the wet flow "sticks" to the vane and goes around the corner better?

DSC_1792 (Large).JPG

[NXBOY]

I've seen it used a bit in smaller cube Apps where Mid-range torque was desired, so I would bet it your right some about helping velocity some, Would take down the CCs of runner a bunch but probably other benefits like your saying.

[modok]

One scheme, you could say it would make the short side act less short.
More wall area could slow it down so the velocity is more even shore side VS long side.

Not saying I believe this, or that it's true, just it's -a reason-.

[user-23911]

Probably just put there so you can cut it out so you can think you've done something worthwhile to mod it.


If it was a round port it would help straighten the flow .........but it's not a round port.

If it was a 4V head, it would make more sense.

[Calypso]

Shifts the velocity profile upper in the port, reduces secondary flow in the bend, guides the flow better around the valve improving atomization and reduces wetting in the exhaust side of the chamber. May lose a little flow depending how it is directed. In my own crude wet flow testing the difference in chamber wall wetting was very clear.

Edit:Years ago someone posted a cosworth paper about it (Duckworth?) here at Speedtalk. If I recall, it mentioned reintroducing fuel form the wetted port walls back into the stream, but it's been awhile and couldn't find it.

[4vpc]

I once stick a fin in the manifold runner before the port splitter in a 2 valve port and picked up a few CFM on the bench, I figured it was preparing the air somehow to make the split and that ^^ is doing the same except to make it round the valve (stem) perhaps, but that was just an uneducated guess.

[NXBOY]

One thing I also noticed was the height difference in the SSR from pic. The tall side is going to be faster and maybe this wall helps with turbelance from other side??

[mag2555]

I can't see from that shot , but if the end of that vane is fatter then the nose ( elongated tear drop ) then it also helps with excessive air speed over the short turn and can be used to get a port out of a tumble condition.

What takes place is that the split air stream accelerates faster around the bulging diameter of the tear drop shape, but as the widest diameter necks back down the split air stream is re-joined at a slower velocity then what it was at the nose of the vane.

When the air stream re-joins it also breaks up any globs of wet flow into more burnable sized condition.

[4vpc]

One thing I also noticed was the height difference in the SSR from pic. The tall side is going to be faster and maybe this wall helps with turbelance from other side??

It might be to aid swirl, DV talks about it in his book.

[NXBOY]

One of them theories that you test and test untill come out with success and hope ya got it figured right. But thats how they make winning power, modify /test/test and keep us Guessing lol.

[mag2555]

When I have played around with adding a vane to the floor of a high velocity port in a tumble condition and that condition stops and the air flow numbers climb, I do think there any guessing left in that !

[user-9274568]

Total waste of time. A crutch. A band-aide, Don't do it, fix the port. About covers it.

[NXBOY]

Some of us unexperianced guys are guessing on this port what I meant. Just trying to make a joke

[mag2555]

I know you likely have tons more experience then I do concerning air flow , but how does one just throw a blanket statement over the whole subject when a I just posted there is clear cut empirical evidence that it can help in certain situations, or are you just trying to save these techniques for your own gain?

[user-9274568]

I know you likely have tons more experience then I do concerning air flow , but how does one just throw a blanket statement over the whole subject when a I just posted there is clear cut empirical evidence that it can help in certain situations, or are you just trying to save these techniques for your own gain?

Is this for me?