Hello everyone.

So I started this topic because I began to ponder a question: which wide body kit is best for a track S2000?
This led me into a much larger question of downforce on the S2k. Being a Motorsports technician I started thinking about how to achieve the best aero balance on the car. It isn't as simple as it looks, especially with the engine so far forward and the fact that the car weighs so little, one could easily overwhelm mechanical settings at high speeds with too much downforce. I am hoping that by discussing aero on the car in general here with many people, we might arrive at some experience based conclusions about the best way to achieve a good aero balance on the car.

So my thoughts, to kick things off:

I think the S2k needs a rather large rear wing, because I would imagine that in high speed corners the rear end is rather volatile. That being said, it would seem to me that since the S2k is a light car, excessive wing would be detrimental to its handling. Also, I think a flat floor for this car is probably a big help, since it keeps the downforce generated more evenly distributed.

So that is also a good question. For those of us that put our cars on the track, what aero upgrade gives us the most bang for the buck?

Your thoughts?

 

Pretty sure there is already a pretty decent sized thread on this.

 

If you can find a consolidated aerodynamic discussion about the whole package I'd be interested to see it. I have found plenty of discussion about a wing or wings, or a body kit, but not an attempt to shed light on the overall aerodynamic balance of the car and how multiple aerodynamic elements can be used in concert in best effect.

 

This should answer most of your questions..

http://robrobinette.com/

 

I'm interested in this.

I have a cr that I'm planning on buying the password jdm under body diffusor. I feel this with the cr wing would provide a lot better aero efficiency and help increase the down force.

I've seen a lot of people running just a rear diffusor but I think that would trap air in the bumper and create more drag.

 

I don't think you're going to find and certainly not be able to create a consolidated discussion thread about optimum racetrack aerodynamics on the modification forum. It's been a while since I read this thread but there is a lot of good, useful information HERE, a thread started by the same individual whose website is linked in a post above.

Besides, in the above quote you mention wanting to find "how multiple aerodynamic elements can be used in concert in best effect." But on the OP you ask about best "bang for the buck." Bang for buck and achieving "best effect" (which implies cost is not a factor) are 2 different things.

 

the under tray in theory should increase down force without increasing drag. It truly is one of the only freebies in car performance/tuning. But, to utilize this advantage, the car needs to be 1 to 2 inches off the ground to utilize the extra down force. the aero on this car is terrible. Wheels stick out past the front fenders, sharp windscreen, and a sharp rear window. Basically think of the rear trunk deck as a pickup trunk bed with a giant negitive pressure zone right behind the rear window.

I'm going to try doing a flat bottom with a rear diffuser. I doubt i'll notice any effects. But one way to tell will be my gas gauge. currently my car gets 270mi a tank. If it gets more or less i'll know drag is at play.

 

Do you have a hardtop? That is definitely critical to getting good airflow around the car.
I think the wing is a smart idea with this car in the early stages. Be sure to make a measurement or two and see if the leading edge of the wing lies at the same height as the roof of the car. In terms of reducing turbulence off the back of the hardtop, the optimal setup is to have the wing lie in the same plane. Airflow tends to "cling" slightly, meaning it can be affected by surfaces near it without touching them directly. The accelerated flow over the wing should be enough to massively reduce any pressure bubble behind the hardtop.

This is the bubble reducing and "cling" effect to which I refer. Note the alignment of the leading edge with the roof, the absence of turbulence where the flow leaves the contour of the roof, and how the flow appears to be "pulled" towards the underside of the wing.


I'm of the mind that the diffuser might do good to the flow as it comes off the back of the car even without the flat floor. Part of the use of the diffuser is to smooth the airflow as it leaves contact with the car, reducing the amount of air that curls back and "clings" to the car, causing drag.
basic effect seen here:
That being said, I wouldnt think it would not create much downforce without a flat floor.

^^^see my above thoughts on the wing and the pressure zone^^^

I agree that for downforce you would need to be 1-2 inches off the ground. There is a difference between reducing drag and increasing downforce, so you may see an improvement because of the drag reduction. The underside of a car with all the pipes and odd shapes is an aerodynamic nightmare. So a lot of drag can be dealt with using a flat floor.

I think the wing+diffuser combo could be the best track starting point, in terms of beginning to correct the airflow off the car.