This thread is scaremongering shit by the op.
That video has nothing to do with engine aero, by cutting your cowl you actually increase flow through the engine bay and directing the air over the wind shield causing extra down force on the car, but it does increase drag.
7.00 to 7:30 talks about air getting under the car, get a front lip to combat that or dont as it will make stuff all difference to engine aero.
Most cars will never see over 145mph, god forbid we all will flip, crash and burn our cars.
Great video full of paid advertising where to get your products.
I think it's a very complex area.
At low speeds the heat from the engine bay will definitely flow out from the gap created by removing the cowling.
I've done it and I can see it when the car is hot and I'm stationary. For road driving which is often alot of starting, stopping and travelling at low speeds then I think removing the cowl is very beneficial. You've removed weight. You've removed material that can heat soak and you are stopping hot air getting trapped.
When on the move at 60mph plus then a pressure wave does does build at the front of the wind shield but this pressure wave is there regardless of if the cowl is installed or not. So with the cowl installed air cannot rise out of the engine bay upwards. With the cowl removed it probably can't either as the higher pressure there will either stop it or slow it. We'd need to measure the pressure created at the front of the car and within the engine bay. So alot of this warm air will probably still be forced downward with the suction created by the fast moving air passing under the car. Basically I think engine bay air flow out of the bay is probably largely unaffected by removal of the cowl when at speed.
Obviously we have a moving car getting cooler external air forced into the bay from the front due to it moving forward at speed and drawn into the bay from the engine and turbos creating a negative pressure. The engine pumps a fair volume of air. A good intercooler is essential in a car like this to benefit from that cooling air hitting the front of the car. Alcohol fuels also do a good job of cooling the charge.
I tried the strings method. I tapped lengths of string on my hood\bonnet to see where the air flow was at low and medium speeds, between 20 and 80 mph.
String between the hood and windshield was forced down into the engine bay at higher speeds.
The thing is the 335 was a poorly designed car when it came to aerodynamics. High speed tests showed the car producing lift at the front and the rear. A front air dam and rear spoiler are a must. A good spoiler can reduce overall drag by lessening the vacuum created behind the car.
I think it's also beneficial to remove all the materials included in the car purely to quieten the engine to the passengers in the cabin. It wasn't about performance. It was about comfort. Rarely do these two things function well together.
