When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
This is from a GM News Article. Text goes with pics below:
How the 2019 Corvette ZR1 Makes 950 Pounds of Downforce
ZR1’s revised front and rear aerodynamics that turn it into a real track basher.
It starts at the nose, where the ZR1 debuts a Corvette-first underwing which Chevy says trickled down from race car world. Air is funneled through a space between the front splitter and closeout panel which generate’s front downforce and helps pinch the air, creating a mild venturi effect which accelerates airflow under the nose (dark blue) and squishes the front tires into the road. You can see how the strakes (turquoise) help guide air through the underwing.
Airflow under the car becomes more turbulent aft of the nose as it swirls around the bottom of the engine and the rear transaxle. A rear diffuser wasn’t possible due to the placement of the Corvette’s stock mufflers.
The key to the ZR1’s two-hundred-and-something top speed is the standard low rear wing. According to Chevy, the smaller pedestal wing creates 20 percent less drag than the optional adjustable high wing, but still generates more downforce than Z06’s wicker bill spoiler.
Serious track shoppers can opt for the available ZTK Performance Pack, which tacks huge endplates onto the front splitter and swaps the low wing for a high mounted version offering five degrees of adjustability. The end plates are creating additional downforce by extending the high-pressure zone (red) further across the front splitter, which also translates to increased pressure (green) climbing up the front fenders.
Whereas the standard setup only shows high-pressure downforce creation at the leading edge of the rear spoiler, the high wing shows high to mid-pressure (orange and yellow) downforce creation over a majority of its surface.
Lastly, there’s the effect of airflow on the car’s cooling. The ZR1 uses the power steering, differential, and transmission cooling module from the Z06, plus five additional heat exchangers– four of which sit hidden behind the car’s gaping air intakes. The side intakes channel air through the intercoolers and brake ducts before spitting it out fore of the front wheels, helping smooth airflow downstream. Air hitting the middle radiator is funneled through the engine bay and out through the LT5’s top-mounted heat exchanger before being picked up with the rest of the air traveling over the car’s roof.
You can also see how the Corvette’s rear quarter panel vents work, air is captured by the vents and forced (yellow) downwards towards the transmission and differential coolers.
This is way too useful. I can see now that the trans and lsd vents don't really add much in terms of drag. Most of the drag on the Z06 comes from the rear wicker bill. It was supposed to generate lots of downforce forcing air over a wide area of the rear windshield...year right. GM just didn't want to spend the money on a frame mounted rear spoiler. You can always learn more from new models about previous models than the new release itself.
Hard to compare what the large wing achieves without comparative numbers but the Car & Driver article said:
"The ZTK (Large) wing offers 10 degrees of adjustability and generates a claimed 950 pounds of downforce at top speed. That’s more than the Z06’s wicker bill generates,(Stage 3 below) and it’s a vastly more efficient way of making downforce (lower drag), which explains how the ZR1 can tack another 25 or so mph onto the Z06’s top speed. "
Below are numbers from a past Tadge post re drag and lift/downforce of all C7s.
Hard to compare what the large wing achieves without comparative numbers but the Car & Driver article said:
"The ZTK (Large) wing offers 10 degrees of adjustability and generates a claimed 950 pounds of downforce at top speed. That’s more than the Z06’s wicker bill generates,(Stage 3 below) and it’s a vastly more efficient way of making downforce (lower drag), which explains how the ZR1 can tack another 25 or so mph onto the Z06’s top speed. "
Below are numbers from a past Tadge post re drag and lift/downforce of all C7s.
The ZR1 has same quarter panel ducts, a more aggressive front end for more downforce and tops out 25mph higher. Some of it is power but 25mph is no joke. I think you would need 1,000hp to get to that top speed in a Z06 Z07. Literally, not joking.
I'm guessing .4 to .45 coefficient of drag. I bet you can nearly flatten that rear spoiler out for neutral downforce/drag.
That wing is worth at least 5 seconds at the ring, the cooling probably another 2 seconds.
Depending on how well those fender vents and hood are, it may push through air better up front than Z06 despite generating much more downforce.
^^^ As you say for top speed you could have the wing as flat as possible. Perhaps cd would be as low as 0.40.
Also agree and extra 25 mph would take more than 105 extra hp for equal drag! Drag is proportional to speed squared. We'll have to see some real numbers!
Most of the drag on the Z06 comes from the rear wicker bill. It was supposed to generate lots of downforce forcing air over a wide area of the rear windshield...year right. GM just didn't want to spend the money on a frame mounted rear spoiler.
I'd wager GM went with a wickerbill first since they probably forecasted the giant amount of butt hurt that the waxer owners would express about a rear wing, as observed with the release of the ZR1. The ones that can't appreciate engineering like track rats like yourself.
I'd wager GM went with a wickerbill first since they probably forecasted the giant amount of butt hurt that the waxer owners would express about a rear wing, as observed with the release of the ZR1. The ones that can't appreciate engineering like track rats like yourself.
No doubt. Look even at Ferrari how much they try to avoid spoilers.
That said once they did attach the spoiler to the frame they didn't just release a ZR1 with a wickerbill as the entry level aero. That to me says the decision could have been driven by cost more than looks. You just can't bolt a proper wing to the rear bumper cover and hope it sticks at 200mph.
I'd wager GM went with a wickerbill first since they probably forecasted the giant amount of butt hurt that the waxer owners would express about a rear wing, as observed with the release of the ZR1. The ones that can't appreciate engineering like track rats like yourself.
The cars & coffee guys swear each coat of Zaino is good for ~.75 seconds due to reduced drag on most tracks.
Speculatively speaking of course.
Yep love "bench racing," everyone is right!
Think I'll put on another coat of Z-2 (no mixing with accelerator,) following immediately with Z-CS (also sets the Z-2) and may even end with a light spray of Z-6!
11-17-2017, 06:02 PM
How ZR1 gets 900 lbs Downforce
As you say for top speed you could have the wing as flat as possible. Perhaps cd would be as low as 0.40.
