I saw this on eBay. Thought it looked pretty interesting and didn't look as bad as some things I've seen people come up with. Would it actually work though as a diffuser and would it work on the car?

 

Purchase it, install it and tell us how it fits. That thing looks like it's more for looks than anything else (like sadly alot of things these days).

 

It looks like it may look alright on the SC.

 

Yeah I agree. I've been curious to see a subtle diffuser on this car for a while. Functional or not I just like the looks of it lol.

 

That won't do jack. Don't buy it. Those fences provide no barrier.

 

Ps:

That's a vortex generator; which means you may even develop parasitic-drag instead.

Smh, get a real diffuser (or make one); this things gonna be a detriment in reality.

 

So where can you get a real diffuser for an SC300?

Any pics?

 

No. That eBay one will be purely for aesthetics. I doubt anyone makes an actual functioning rear diffuser for this platform because R&D costs to do such a thing would be huge. Unless you're tracking your car a rear diffuser is pretty pointless as it will slow you down in a straight line.

 

I would get one for looks since my car is slow.

 

None of that is true.

You can make a diffuser with sheet-metal.
The optimal angle is 8 degrees; according to exotic-car manufacturer designs. The space between each fence is more or less negligible; unless you're racing professionally, then you can kinda "eye it"; rather than have exactitude; unless you have a visual-means of experimenting with airflow.

The Venturi-Effect is how diffusers work; the larger opening in the rear produces a greater vacuum; fascilitating incoming flow from the front (Dynamic Pressure); which thereby reduces the pressure-zone beneath the vehicle, creating downforce (Bernoulli's Principle).

It'll work on just about any car, provided you're using an undertray. Our challenge is simply that nobody's made one for SC's.

 

Agree to disagree. I understand the principle of how they work, but just because something works one way on a certain platform doesn't mean it's the same on another. There is going to be some design overlap applicable to any platform but without performing actual air flow testing you cannot say it makes any improvement. This is why actual race teams spend tons of cash on chassis and aero development. Just bolting on some poorly designed piece can actually increase drag and turbulence defeating the entire purpose of a rear diffuser in the first place. If you're buying a universal piece off of eBay expect it to be purely for aesthetics.

 

I meant "a" diffuser; not this, or any particular one.
The theory is universal; the dimensions are what differ, car to car.

 

The only one I have seen that actually is a "real" diffuser and not for looks was built by rare fab for an turbo sc400.

They might be able to see if can make another one.

 

The purpose of a diffuser is to slow the air velocity so the static pressure increases. Why? Because when the static pressure at the rear of the car increases the pressure drop from the front of the car to the rear is lessened. Less delta pressure across the vehicle means there is less drag. The depicted diffusers are hardly worth considering. The angle of a usable diffuser is very small. Once the airflow separates from the diffuser wall, there will be no more increase in the static pressure. Hence, it just quits working. You must have a smooth flow entering the diffuser for it to do anything. Consequently, the need for a smooth surface on the bottom of the car.

To determine how effective a diffuser might be on a particular car it should be determined by wind tunnel testing. A model would be made and the drag coefficient, CD, could be accurately determined. This is done all the time in aircraft design. One could test a model and then retest with a "diffuser" installed on the rear.

 

I'm sorry, but none of that made any sense (at least not to me).

There is no "static" pressure. It's a moving vehicle; so all pressure is "dynamic".
Secondly, there is a steady stream beneath the vehicle, starting front to back; known as a laminar-flow.
The pressure-reduction occurs directly beneath the vehicle, within that flow; so the area of greater (atmospheric) pressure is outside that area. The exiting airflow out the rear, always produces a vacuum, called a Venturi-effect; which facilitates the flow from the front, in order to increase its velocity; thereby lowering the pressure (Bernoulli's Principle) under the vehicle, creating downforce. In sum, you're turning the car into a wing; pulling itself down to the road more firmly; just like the rear one does on your trunk.

The fences, which are the dividers/fins help keep maintain the flow, by creating a barrier from outside air potentially entering to disrupt it. They keep the stream "neat" in a sense.

All of that might be what you meant; I'm not ******* your post; it just sounded really convoluted the way you wrote it IMHO.