Can the mph that raises the rear spoiler be changed?

[Topless]

Originally Posted by KRAM36

In the youtube video it says the spoiler on the Porsche creates more drag at the rear of the car.

" the redirected air leads to a lower pressure zone behind the car, which can increase drag"

Having the spoiler up will not improve the mpg.

I guess we will just have to agree to disagree then. Tailgate up always improves highway gas mileage on a pickup. The Boxster spoiler operates under the same principles. Separated bubble.

[KRAM36]

Originally Posted by Topless

I guess we will just have to agree to disagree then. Tailgate up always improves highway gas mileage on a pickup. The Boxster spoiler operates under the same principles. Separated bubble.

The air flow over a truck bed is completely different then the air flow over the rear of a Boxster. You're video proved it would lead to more drag on the car.

[Topless]

Originally Posted by KRAM36

The air flow over a truck bed is completely different then the air flow over the rear of a Boxster. You're video proved it would lead to more drag on the car.

And if the spoiler created more drag, why did the car with a spoiler outperform the car with no spoiler in straight line testing??
1st- Car equipped with wing
2nd- Car equipped with spoiler
3rd- Car with no spoiler or aero device.

Hmmmm... Still so much to learn Grasshopper.

[KRAM36]

Originally Posted by Topless

And if the spoiler created more drag, why did the car with a spoiler outperform the car with no spoiler in straight line testing??
1st- Car equipped with wing
2nd- Car equipped with spoiler
3rd- Car with no spoiler or aero device.

Hmmmm... Still so much to learn Grasshopper.

Sorry, but that guy doesn't know what he is talking about in the straight line test. The car with no spoiler and identical to the cars with a spoiler would win the straight line race.

Read the comments on the video. "The main argument though was that spoilers make you faster in a straight line, which is false."

[Topless]

Originally Posted by KRAM36

"The main argument though was that spoilers make you faster in a straight line, which is false."

Got any wind tunnel data to support that? Thought not.

[KRAM36]

Originally Posted by Topless

Got any wind tunnel data to support that? Thought not.

Do you?

You have to be kidding me if you think spoilers make a car faster in a straight line.

They create drag, they press the car to the ground which takes more power to move the car.

[Smallblock454]

Originally Posted by KRAM36

Do you?

You have to be kidding me if you think spoilers make a car faster in a straight line.

They create drag, they press the car to the ground which takes more power to move the car.

Yes and no.

An ideal spoiler should generate downforce. At the same time it should reduce the drag coefficient by optimizing the airstream. So if it is designed well it should not make the car slower but generate downforce.

Other aspects: front and a rear axle have in general different down- and upforces. So you have to optimize the whole body system aerodynamicly.

But if you can drive only 55, i think there is no need for big aerodynamic experiments.

Regards from
279 - that's the number i get in my instrument cluster on the flat Autobahn.

[Topless]

Originally Posted by KRAM36

You have to be kidding me if you think spoilers make a car faster in a straight line.

They create drag, they press the car to the ground which takes more power to move the car.

Quite the opposite actually. Instead of creating downforce our spoiler "spoils" lift and often but not always reduces Cd. Airflow lifting several hundred lbs on the tail of the car causes a low pressure zone, turbulence and drag. Solve that and you improve stability, fuel efficiency, and straight line speed. Porsche aerodynamicists understand this, tested and confirmed it. Some grasshoppers not so much.

The modern 991 Turbo takes it a step further with active front and rear spoilers but the goal is the same. Stability, fuel efficiency and straight line speed with the lowest possible Cd. https://www.youtube.com/watch?v=A9FluxQn0ZE