Windage tray HP diffrences

352Ford2

New Member
Oct 12, 2005
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Seattle,WA
A while back I was reading about windage trays and this mag (I think it was pop hotroding) did some dyno tests proving that mesh windage trays make more power than the louvered ones. My theory has always been that the louvered ones were better because they kept the oil outside the tray off the crank better, but these guys were thinking that the droplets inside the tray on the louvered one were bouncing back off of the tray onto the crank and that the mesh kept that at bay.

Thoughts anyone, other dyno tests, etc?
 
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No actual data or proof, just theory: I tend to agree with you because the whole purpose of the windage tray is to keep the oil away from the crank throws. As the Revolutions of the crank increase, the amount of power that each counter weight needs to get past the oil also increases. I have heard it's anywhere from a 10 to 20 horsepower increase depending on what direction the wind is blowing that particular day.

Sneaky power / Free power = cool!

The only way the mesh one could work is when the mesh is so thin that the surface tension of the oil is too great to pass through the openings in the metal
 
well in the crank case, its pretty much a thickass oil cloud at descent to high rpms. I would say the difference between the 2 are negliable in a street motor. i could see a high horse drag motor. BUt seriously, if you're that worried just have the crank throws knife edged.
 
i have seen many a dyno test that actually proves 6 rwhp to 10 rwhp in mags with just a windage tray addition. I would say the difference between the louvered and mesh trays are not much. Just one company with the patent on 1 way to build em claiming more hp then the other guys patent.
 
seijirou said:
You know. Aerodynamically it would make more sense to knife-edge the trailing edge of the counterweights rather than the leading edge.

Just a random thought.


yes and that is why I have always thought that people that knife edge cranks (they always do the front side) never passed aerodynamics 101
 
The knife edge on the front helps deflect the impact of the crank hitting the oil i think. For sustained movement through the oil... yeah the trailing edge might be better but its the difference of chopping through the oil rather than pushing.
Kevin
 
Sicarius428 said:
The knife edge on the front helps deflect the impact of the crank hitting the oil i think. For sustained movement through the oil... yeah the trailing edge might be better but its the difference of chopping through the oil rather than pushing.
Kevin

movement through any fluid (yes air is a fluid in fluid mechanics) the back side is always more important than the front, but you really shouldn't look at it that way, its a system. the changes you make upstream affect downstream.


end result :knife edjing the front does esentaly nothing
 
i think you guys may need to read up on your fluid mechanics...b/c the frontal cross sectional area also has a dramatic effect on resistance. Reducing the effective frontal area does indeed increase efficiency. Think of a corvette compared to a fox body...the frontal area is much smaller on the corvette making it slice through the air much better. Or look at a porsche, small in the front and tappered/curved in the rear...the best design! I do however agree w/ you that knifedging the trailin edge may also improve performance. Something someone should try and dyno test for results.
 
There is a common misconsception about drag coefficient. It's counter-intuitive. Yes having a pointy front does help you "slice" through the medium in which you travel. People think that slicing through air must be so much better than pushing through air because they assume it must be similar to cutting through a solid, where sharp is key. However, especially with air, the energy required to push a blunt frontal cross-section through is a drop in the bucket compared to the energy required to overcome the vacuum generated by a blunt rear cross-section. That Porsche will actually have less aerodynamic drag going in reverse than it has going forward. If you really want to see automobiles designed to be as aerodynamic as possible, find some pictures of solar powered vehicles. You'll see many are teardrop shaped, blunt side forward.

Through air, the benifit of a pointy front is neglegable untill you approach sonic velocity.
 
seijirou said:
There is a common misconsception about drag coefficient. It's counter-intuitive. Yes having a pointy front does help you "slice" through the medium in which you travel. People think that slicing through air must be so much better than pushing through air because they assume it must be similar to cutting through a solid, where sharp is key. However, especially with air, the energy required to push a blunt frontal cross-section through is a drop in the bucket compared to the energy required to overcome the vacuum generated by a blunt rear cross-section. That Porsche will actually have less aerodynamic drag going in reverse than it has going forward. If you really want to see automobiles designed to be as aerodynamic as possible, find some pictures of solar powered vehicles. You'll see many are teardrop shaped, blunt side forward.

Through air, the benifit of a pointy front is neglegable untill you approach sonic velocity.



right on the money, glad to see I am not the only one who passed engineering 101
 
I passed engineering.... The front of the crank throws should be rounded not 100% square, then the back should taper off to a point or wedge. Just to clarify

Like the shape of a wing. Are we talking about flight or windage trays still?
 
srothfuss said:
I passed engineering.... The front of the crank throws should be rounded not 100% square, then the back should taper off to a point or wedge. Just to clarify

Like the shape of a wing. Are we talking about flight or windage trays still?

Almost like a wing, but not 100%. Remember a wing has a curved upper surface with a flat lower surface to create lift. You wouldn't want to have a crank throw creating horizonal lift and trying to walk the crank forwards or backwards now would you :rlaugh: :nice:
 
I passed engineering aswell...and srothfuss is right...the best combination would be a rounded front and a tappered trailing edge. its pretty simple if you still dont believe that reducing frontal area helps reduce drag...look at everything designed for aero and you will find a tendency to have the smallest actualy leading edge area. I understand that solar cars are tear drop shaped...but you have to realize the front of those cars still come to a small rounded point in the front....a crank counterweight will follow the same laws of dynamics and fluids plain and simple. Also you would never design a counterweight like a wing...i dont think that what anyone was implying.
 
Too bad my engineering path lead me to injection molding interior parts and trim pieces. Not that I don't like my job, but it isn't the coolest part of automobiles these days.


And of course, I didn't mean that we want the crank to be rocking back and forth with a wing shaped throw. But let us just think that if we had two identical wing shaped (each oppisite of each other) wouldn't any lift generated by said two crank throws be canceled out? Would that also prevent movement of the crank for aft? Or does the constant change in fluid ruin this topic?