i´m trying to convince you guy´s that IF you have something in the way for airflow it should have a smooth edge at front and an sharp at the back to 'steer up' the flow so no turbolence will accur..
and it doesn´t matter if it´s a valve or a 'wall'
and for more torque if you get an smoothe edge,,
well it goes hand in hand..
more air into engine = more torque.
and more torque in an V8?
that´s bull.
look at the powerlevel and at what rpm´s it´s at.
then ofcourse a v8 has more torque..
it has more litres.. DOH!!
i´m just here to f**k your safe world up a little =)
ps,
i have quite long experience in engine tuning..
A knife cuts into things much better than a pencil does.
You are correct that if a valve guide or similar object HAD to be in the way of airflow, then it would be best to have a knifed rear edge and a radiused front edge.
However, when you have the opurtunity to knife edge the front, of course it will have less drag than something that is thicker. You have put restrictions in place that are not there.
In this instance of where the port splits in two, knife edging makes sense, and will cause less of a restriction to air flow that just radiusing the front end.
I'm inclined to agree that a curve will oddly flow better than a knife edge.
Things like rudders on boats, proppelors, the vertical tails on planes all have a curved front face.
If your knife edge is not exactly spot on symetrical and the cross sectional air pressure comming down the post is not exactly even, then when you split the port with the knife edge you will not have equal pressure either side of it. This would cause a swirl around this edge as the pressure tries to even out I think.
A curve like the bellmouth of a TB trumpet on the other hand would allow the air an easier path to kind of 'decide' which side it wants to go down to even out the pressure.
I think the aircraft wing analogy was good. The lift from the wing is the top and bottom curves. The frontal area curve is more just like a splitter. Drag is an incredily key factor for aircraft, if they could reduce this surely they would.
Ohhh, I can think of more.... Space shuttle nose cones are curved not pointy, and big misiles.....
Disclamer: "All this stuff is just spewed from my brain and not based on any sound reasearch at all..." lmao
you have to take the things out of it´s working area to understand.
raise up an 'knife' against the wind
and raise up an airplane wing against the wind.
the wing will have lower cw value. due to less turbolence
BUT!!
as i said above,
it´s important to have a small frontarea as well.
but still the edge should be smooth.
an experiment i done for a couple of years ago..
first you take an waterdrop shape and mount it at a kind 'libra'?
with a counterweigth and an axle with a hole in between those.
an adjust the both to the same weight.
then you take an hair dryer and blow downwards on the waterdrop shape..
if you turn the smooth edge up the libra did´nt move almost anything.
and if you turn the waterdrop shape 180 degrees with the spike upwards.
It moved a LOT..
then you mount an 'pin',nail or anything.
and do the same
and you will find out that it moves more than the waterdrop shape with the smooth edge upwards..
...anyway. I think that the very reason we differ is because you're looking at airflow being the same over very differing circumstances.
The reason the 'droplet' shape moved more when you had it with the 'spike' upwards is because of the low pressure point created on the other side of the head of the drop. Thus, as the air rushes to fill the low pressure, it causes turbulence, and the drop moves all over the place.
Place the other way, and the smooth transition from large to small on the low pressure side of the drop, which is now the spike end does not create turbulence, and theres no air rushing about.
This all occurs because of the low pressure side changes (ball to spike) this is the reverse of the head operation. The low pressure side is already determined, as it's the inlet valves in the combustion chamber. You cannot change it. All you can change is the initial split for the air coming in, which in my book is best to be as thin as possible whilst still maintaining a smooth transition into the inlet valve...
or you could say the more dense media the more sharp the edge should be.
and for fuel engines that run max power at lambda 12.6-1 there arent that much 'wetness' in the gas..
in your case when you´re running alcohole as media it leaves less power with same lambda.
you are going for more like 5-1 huh?
then YOU should have more sharp edges than on an petrol engine..
exaclty..
But i think in my mind, the air and water media is really near the same if you compare..
Get out of airplane with shape in foots, the plan shape will "brake" much more than a curve shape...
yeah.. is really diferent case the siamese inlet port, than a comom 8V head with one port for one valve. The example of contour of valve guide is really diferent case than siamese "wall" in 16V head.
My conclusion is: "Make a knife for high revs!!!"
cant u just take the droplet theory.....and turn it round,
so the sharp tail is the split, and the ball disapears into the head's metal??????????
i aint a clue, il leave my head work to 16vastra if he's stil up for showin me
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