Does the C8 wing make any practical difference? From what I've been able to learn so far it seems the wing is for appearance only in almost all circumstances. The only specific numbers I can find are below, and what downforce is created at 180 mph is not relevant for me or almost all C8s I imagine, as virtually no one is turning a corner at 180 mph. But if you only get an extra 100 lbs added to the weight of the back of the car while turning a corner at 100 mph, which is still very fast unless you're on a fast racetrack, I can see little point to the wing on a 3,600 lb car.

"Specific downforce figures at different speeds for the Z06 are also available, such as 16.5 lbs at 40 mph, 37.2 lbs at 60 mph, 66.2 lbs at 80 mph, and 103.5 lbs at 100 mph."

Is there a graph anywhere that shows downforce amounts vs. speed for different wing types? Is there an realistic argument for including a wing for other than appearance for anything but the highest speed track scenarios?

 

You can do the math based on the dimensions of the wing. Aero has a cross over point where it generally begins to be relevant at around 80mph. This is an extreme oversimplification. None the less down force becomes more effective as the magnitude of force increases, which amounts to how much drag the wing experiences. Go faster = more air flow = more downforce generated over a wing surface.


The amount generated by the OEM wing is a small amount and any bit of downforce above zero is beneficial. How usable that becomes depends on a lot. You have asked a series of good questions with fairly complicated answers.

For instance the weight added by downforce is more important in transient conditions like a turn where weight transfer changes the balance of the vehicle. How much influence an amount of weight of a corner also depends on a lot.

In short, yes it makes downforce, yes it yields some benefit. How much benefit is based on use case scenario, if it's a weekend cruiser and you're not doing felony speeds no of course you don't need the wing. Example: 911gt3 rs vs 911 gt3 touring. Wings can look cool and serve a function, looks are of course subjective. Function requires purpose and deliberate decision making.

 

As TX Chassis Tuner eluded to in short, yes the Z51 rear spoiler IS beneficial to high speed stability. "How much?" The benefit(s) are entirely negligible unless you are doing felon speeds and/or driving entirely reckless for public roads. Tracking it on a higher speed road course? Get the spoiler, but then again you'd already have one bc you'd definitely want the Z51 package for that kind of work anyhow.

 

No need to calc coefficents.

You just need one point on the curve since down force is zero at 0mph.

downforce @ new speed = downforce @ old speed * (new speed / old speed)^2

 

Most aren't using the downforce anyways. They are so far from the traction limit in the high speed sections. Probably be faster overall without the extra drag in the straights if you're just going to park it in the scary stuff.

 

True enough that will get you close enough.

Also true 99% of people will never get to the point where they are utilizing all of the mechanical grip. So adding downforce will be very niche / use case oriented.

If the car was built from scratch to be aero dominant that is a different story altogether.

 

Yep, close enough for estimation. In real life, the flow geometries change slightly with stuff deflecting, the car squatting, etc. Still should be within 5% to 10% of the theoretical quadratic curve.

 

I have actually been wondering about down force at various speeds and ride heights. I know lowering has an adverse effect on the MSRC but never heard about aero.

 

Ride height has the potential to affect aero balance. If you add more rake you will change how each end of the car interacts with the airstream. In the case of lower front vs rear, you will remove downforce from the front of the car and cause understeer.

It is so sensitive, for example, that race teams take into consideration the change in aero balance as fuel is consumed which changes the ride height at one end of the car dynamically over time.

 

The spring mountain instructors sure didn’t have a lot of great things to say about the Z07 aero. ‘Negligible’ about sums it up. They also said the Z06 under steers too much with the PS4s they run which is a true story.

 

Understeer is pretty much typical for a factory street car. I have yet to own an American sports car that oversteers from the factory.

As for negligible, I can see that compared to an actual race car. Z07 is toted as a street legal race car. Though there are still large differences between a Z07 and it's real racing counterpart. But compared to a stock Stingray or Z06, it's nothing to turn your nose to.

 

Seems to me someone could put a strain gauge on the suspension on each corner of the car and measure the loads in real time???

 

Actually, wouldn't the MSRC be able to measure this? I haven't a clue how to access the data but I imagine it is already being measured in real time.