Front End "Splitter"?

[cfg83]

Hello -

I got this from here :

Aero Basics
15 February 2007
http://autospeed.drive.com.au/cms/A_107773/article.html

Splitter

A forward protruding "splitter" catches on-coming air against the frontal area of the car and prevents it from spilling underneath. Instead, the air is forced to travel up and over the top of the car or down its sides. This air also has a downward acting force that pushes onto the surface of the splitter, as the high pressure in the front of the car tries to escape. Plus it puts more air through the rear wing (if there's one fitted).

A splitter works best on cars with a blunt front end that gives a large frontal high-pressure area to use. However it can also change the car's front "stagnation point", which is the point on the front of the car where air strikes and splits either upwards or downwards into different directions. By moving this stagnation point, the strategic location of intake ducts in a previously high-pressure area may be effected. It can also create a near drag-free source of downforce.

When I see the little "arms" holding up the splitter, I imagine that they can stretch out at highway speeds. If this were true, then the splitter could be pushed down and would reduce the amount of air that travels under the car, thus helping Cd (right?!?!?!?).

What do you think?

CarloSW2

[Peakster]

I think the theory is definitely believeable. With front bumpers that angle downward, this device would most certainly help prevent air from ramming under the car:

Attachment 231

Edit: I found someting else interesting in the same article:

Another trick that reduces both aerodynamic lift and drag is to sharply cut away the car's rear trailing edge - thus preventing attached flow wrapping over the end of the boot-lid.

Does that explain why the Vesta 2 Research Vehicle has a Cd of only 0.19?

Attachment 232

That's a shockingly low Cd for a vehicle with a huge wake behind it (no boatail).

[hotroddr]

Im in the process of fabbing a splitter for my rabbit. There are big benefits to more downforce(actually in reality it is less lift) and less air going under the car.
Those turnbuckles do not stretch, they are to keep the splitter parallel to the ground. A splitter is usually an extension of an air dam. Most race cars have huge splitters. Search for DTM race cars for more pictures

[cfg83]

hotroddr -

Originally Posted by hotroddr

Im in the process of fabbing a splitter for my rabbit. There are big benefits to more downforce(actually in reality it is less lift) and less air going under the car.
Those turnbuckles do not stretch, they are to keep the splitter parallel to the ground. A splitter is usually an extension of an air dam. Most race cars have huge splitters. Search for DTM race cars for more pictures

Ok, that's what their called, turnbuckles. DTM racing, got it.

One reason why I am imagining the stretchiness was that I am thinking about an air dam that would get pushed down at highway speeds, but have clearance at street speeds. At highway speeds, when there is more air friction, there would be less turbulent air going under the car. Instead of turnbuckles above the air dam, my original thought was springs under and/or behind the air dam. The stronger the spring, the less the air dam would be pushed down. I think it would require a cost/benefit analysis of increasing the frontal area vs. reducing the turbulent air under the car.

CarloSW2

[hotroddr]

You can accomplish a similar thing with a regular air dam. Extend it low and it will drag sometimes but as long as its reinforced from behind it will hold up to highway air forces but collapse and then spring back when it hits the ground. My air dam on my cavalier was like this, A better thing to do than how I did it would be to fabricate a similar thing on the very front of the car instead of under it.


See how the angled plastic piece helps hold the dam in place while allowing it to flex when it hits the ground? That idea could be used on the very front of the car instead of under the radiator where I used it. I extended the air dam because I completely blocked off the grill on my car.

[cfg83]

hotroddr -

Ok, that's cool. It looks like you scavenged plastic from another bumper/underfairing from another car.

What I really like is the combination of "grill block + air dam extension", a good compromise, especially for Arizona.

CarloSW2

[GasSavers_Ryland]

I would imagine that an air spliter would help push more air around the car, insted of over it, simaler to how those little upright wings on the tip of air plane wings help to hold the low presure from rolling over the tip of the wing.
A problem that I have with air dams is that they rub on the ground, and curbs, and act as a little snow plow, creating a pile and getting the car stuck.