Hard "on the right front". Why?

[MasterSbilt_Racer]

you cannot have downforce without air getting under the car. downforce is created by equal amounts of air moving at different speeds . without air under the car all you have is drag

this aero influence does contribute to the setups many teams use and is partly the reason we try to keep the frontend relitive to the race track.

Downforce is a difference of air pressure on opposite sides of a surface. Can be achieved by having different speed airflows on each side or by simply having much less air on one side. The advantage of a vacuum under a race car was demonstrated in the 1960s with the Chaparral 2J.

[Matt49]

Downforce is a difference of air pressure on opposite sides of a surface. Can be achieved by having different speed airflows on each side or by simply having much less air on one side. The advantage of a vacuum under a race car was demonstrated in the 1960s with the Chaparral 2J.

Exactly! There's a lot to be said for keeping air OUT from under the car yet letting it escape out the back. Thereby creating a huge low pressure area. I'd love to get some pressure readings from just under the decking of a late model at speed on the track compared to just above the decking.

Remember a few years ago when some guys were trimming their LF quarter panels almost completely off? With the way the LF QPs are tapered in at the back, it creates a major hindrance for air trying to evacuate out the back (especially when the car is yawed out). I guarantee they weren't doing that because they thought it looked cool. Somebody figured something out and I'm guessing officials put a stop to it.

[Brian Gray]

Take air away from the high speed area of an airplane wing and tell me if it will still stay airborne.

If the air isn't under the car there is nothing to escape out the rear. You can disagree all you like but the physics don't lie.

[Ghopper]

Take air away from the high speed area of an airplane wing and tell me if it will still stay airborne.

If the air isn't under the car there is nothing to escape out the rear. You can disagree all you like but the physics don't lie.

Brian - The high speed side of a plane wing is the top (longest side) to create lift. I think your argument is not going the right way for a late model application. If applied to a latemodel, with equal flow above and below the car would also cause lift, as it is a longer distance over the top than the bottom.

We get much of our downforce from high pressure areas (nose, spoiler). More like angle of attack for airplane wings. In this case you want minimal air under the nose of the car. In cases when you have a splitter (like NASCAR), a small amount of air can be beneficial.



Ghopper

[hucktyson]

As usual Brian Grey is a toss off , wind tunnels don't lie Brian

[Brian Gray]

Brian - The high speed side of a plane wing is the top (longest side) to create lift. I think your argument is not going the right way for a late model application. If applied to a latemodel, with equal flow above and below the car would also cause lift, as it is a longer distance over the top than the bottom.


We get much of our downforce from high pressure areas (nose, spoiler). More like angle of attack for airplane wings. In this case you want minimal air under the nose of the car. In cases when you have a splitter (like NASCAR), a small amount of air can be beneficial.



Ghopper

The physics don't change because its a late model.
And Huck you obviously haven't spent time in the tunnel.

The effects created by a splitter are the exact reason the xd4 front end out perform every available nose on the market.

[Brian Gray]

Please revert back to post 18.

[Brian Gray]

As far as answering the question I believe you are asking originally. Why the cars are so pinned over on the right front? Rephrase .

My opinion is most cars now days are so hooked up with the 4 bar spring behind they are trying to eliviate the left rear drive to help the car turn while attempting to retain forward drive which is why typically the cars that are fast stay straight and flat through the corners. Just my opinion.

[hpmaster]

Comparing an airplane's wing generating lift to a car's surfaces generating down force is like trying to trim your hedge by flying a helicopter up side down.

[Matt49]

Please revert back to post 18.

You don't want air going under the car. If air is going under the car, then the air evacuating out of the back is just creating air FLOW and NOT a vacuum/low-pressure area. If you can stop air from going under the car, the openness of the back of the car creates a vacuum. That in combination with the high pressure areas above created by the nose and spoiler (and decking if your attitude is correct) is what gives us downforce. If we wanted air under our cars, then why do ALL of the top teams run valences that leave almost zero clearance between the nose and the ground when the car is at racing stance?

[Ghopper]

The physics don't change because its a late model.
And Huck you obviously haven't spent time in the tunnel.

The effects created by a splitter are the exact reason the xd4 front end out perform every available nose on the market.

Brian - Please.....we have all been off the mark and had to study hard to find answers. Unless you were on a rolling floor tunnel with minimal blockage, then I don't think you were getting good answers for your stall point of the front splitter.

I am on the shaker and compliance rig side of the automotive/race engineering. My friends are in the CFD/physical tunnel side. So I have to rely on what they tell me over beer. For my humble comment: I can also say my wife did better in physics than I did, so I was not the rock star student and have been wrong before.


Ghopper

[hpmaster]

The Bernoulli principle, only about 300 years old, explains and validates what Matt49 is saying. Nuff said.

[Ghopper]

The Bernoulli principle, only about 300 years old, explains and validates what Matt49 is saying. Nuff said.

HP - Bernoulli applies to airplane wings in a flow field, were the same flow is on both sides of the wing. (Maybe that is your point). At least that's how I remember it, but maybe I need straightening out.

Overall I am with Matt49. But I would not apply Bernoulli as the primary downforce to a latemodel as the flow never the same on top and bottom. I am sticking with flow that is not horizontal to the surface (mostly used in Bernoulli principle ), creating high pressures against angled surfaces, and hopefully as little pressure under the car as possible, through road surface interaction and venting (back of car, wheel wells, left side higher than right with a 10-15 body slip angle).


Ghopper

[hucktyson]

Brian you could sell everything you own racing related and still not afford wind tunnel time. I have seen real data from a well respected high level engineer who has been there and done that.

[Brian Gray]

I believe we are in an argument just for the sake of argument. I am simply stating you cannot have one without the other. Air under is a requirement. Like I said the physics don't change. Without air under the car the down force is simply drag. Not free tire loading. Does that clarify?