My son sent me this item from Corvette Blogger:
https://www.corvetteblogger.com/2025/10/21/video-this-record-setting-c7-corvette-zr1-literally-melted-during-a-118-mile-open-road-race/
It’s a story of a 2019 Corvette ZR1 that melted and charred its rear fascia after a very long run at speeds up to around 200 mph.
So why did the rear fascia become so badly damaged?
Sure, engine exhaust is plenty hot. I’ve seen plenty of photos of red-hot exhaust headers on dynos, and seen red-hot headers firsthand in a Dodge custom van (remember those?), driving hard with the engine cover removed. There are some YouTube Corvette videos taken in dim light showing blue flame out the tail pipes. Lots of heat.
In a gasoline engine, the heat from the fuel you burn is proportioned roughly: 1/3 to make horsepower, 1/3 goes into the radiator coolant, and 1/3 goes out with the exhaust gases. So at wide-open throttle, a 755 hp engine also puts out about 755 hp as exhaust gas heat, which equals 563 kilowatts, enough for 5,632 old-fashioned 100-watt incandescent light bulbs. Over an hour, that’s about 2 million BTU. Your home furnace is probably around 150,000 BTU.
But, exhaust heat usually mixes and dissipates into the cool, surrounding air right after it leaves the tail pipes. So what happened to this Corvette?
A fast-moving car normally has a wake behind it – negative pressure, a.k.a. a slight vacuum and that creates some of the drag a car must overcome to go fast. But we normally don’t see much evidence of heat damaging the back of racing Corvettes. Again, the hot exhaust mixes with turbulent, cooler air behind the car.
But this ZR1 had the big ZTK wing. An airfoil, or wing, is a device that causes partial vacuum on one side and positive pressure on the other, with relatively low drag. In an aircraft, ‘lift’ is actually caused more by vacuum on the top of the wing. Yes, pressure will build up on the bottom of the wing when the airplane’s nose is lifted or the flaps are lowered, but that causes lots of drag.
On a car, the wing is turned upside-down to pull the car downwards without creating a lot of drag. And the big endplates on the Corvette ZTK wind keeps that vacuum under the wing, with less vacuum spilling off to the sides.
And, airflow under the car is intentionally restricted to reduce drag.
So now we have much more of a vacuum at the rear of the car. Apparently that vacuum pulls airflow up from the back of the car and that air includes lots of very hot exhaust gas. It ‘washes’ up over the rear fascia, heating it. That’s how they ended up with a ‘toasted marshmallow’.
What could be done to prevent this? One idea: add much longer tail pipes.
