7 replies to this topic

[Jhope]

Why do Nascar teams add tape to several parts of the car, the radiator for example, and say that it improves downforce? If I understand anything from this, it's that it reduces drag and creates a smoother airflow over the car. But why downforce?

[random]

The car produces more downforce when the vents are closed off, but of course taping the vents reduces cooling. So the tape is actually just a method of adjusting between cooling and downforce.

If the car is running cool they can add tape, if the car is running hot they can remove it. They can also apply the tape for a short stint for extra downforce. Sometimes they'll just tape part of the vents for a happy medium.

Why does it provide more downforce? I suspect because with the addition of the tape, the airflow is going over the bodywork instead of through it. Just as an airplane wing with holes in it wouldn't work as well as a wing with a uniform skin.

[CFD Dude]

The tape helps the downforce some, but it's more for drag reduction than downforce. The closing off the radiator openning dramatically cleans the aerodynamics of the car. The downside is that they radiator gets less air. Before the one engine rule, the would run qualifying with the front completely taped off. They might not do anymore to save the engine for Sunday, I'm not sure.

[Wuzak]

Would taping the radiator inlet effectively reduce lift because it reduces the amount of air being forced into the engine bay area?

[wegmann]

Definitely. An example of this is described in the book "Driving Ambition: The Inside Story of Mclaren F1" by Doug Nye. They tried several configurations for their intakes and radiator inlets because some of them had bad aerodynamic affects on the car. If I remember correctly, they ended up pushing some air to the engine with a fan to help out. This was effectively a moving aerodynamic device on the car!

[TenTenths]

The fact that they use "duct tape" to enhance anything on those cars is another reason for me not to watch NASCAR.

I do not understand why they are so afraid of technology.

[CFD Dude]

Wuzak, you're right, reducing the air under the car will decrease the lift on the car. The downforce comes from the bottom of the car being sealed off from the top. The ground effect sucks all of the air out from under the car and creates a vacuum effect under the car. The closer to the ground the car is the better this suction is, that's why there are such large fines when the car is a 1/16" under minimum ground clearance. It seems kind of the opposite from F1 where you try to move as much air as possible under the car, but with big empty bodywork and no diffusers it's the best you can do.

TenTenths, I'm the last person to defend NASCAR, but if 'speed tape' is a reason to stop watching a race series the be prepared to stop watching just about every form of motorsport. The stuff is invaluable for fixing bodywork damage during a race, keeping wires and cables out of the way. It's not a great fix but if it gets you to the finishline... Sportscars use it all of the time for covering brake ducts at tracks where the don't need them. It's only because F1 can afford to have a score of spare bodyparts in the garage that they don't use it.

[Ben]

I agree that NASCAR sucks, but this is hardly a good reason. Duct taping of air intakes is almost universal across the board in motorsport as a quick fix.

Another common situation is a very cold test session, where you might tape the duct to ensure that the engine heats up properly.

Ben