[Robin]

Also, Ford (in the UK) found that this spoiler -



created nearly as much downforce as this one -



Due to the boot (trunk) being longer and the air flowing over the car differently, 'pushing' on the bootlid as well as the spoiler.

I'm sure BMW have no doubt found similar over the years, a little lip can generate a lot of downforce, as Mr Dan Gurney himself found in the 70s.

[Vudoo4u2]

Just to clarify my initial post..I was joking

[SteveMondragon]

After I put my oem M3 spoiler, my car is a lot faster

[Mooreski]

Originally Posted by Robin

Downforce has nothing to do with mass, but it does technically have something to do with weight.

Formula 1 car downforce figures are often quoted in kilograms, at a certain speed, a spoiler can add a certain amount of 'weight' to a car. Dynamic weight, not static weight (AKA mass)

If you could weigh the car in a wind tunnel, it would get progressively heavier as the speed of the wind increased, even though the physical mass of the vehicle is unchanged.

I'm not picking a fight, just having a geek moment.

Bring the geek!

Not sure I agree with this. Weight is the force exerted on a body by gravity. Aerodynamic forces are different. You're correct the car would appear to weigh more when increasing air speed in a wind tunnel. But that's from measuring the combination of gravitational forces (weight) and aerodynamic forces (downforce)!

[asdflkijd]

it adds 5 points to your cock-o-meter and 10 horse power hehhehe

[Vudoo4u2]

Here is your real concise answer for the OP:

IT DOESNT DO ANYTHING YOU WILL EVER NOTICE...but if you like how it looks, get it

[Robin]

Originally Posted by Mooreski

Bring the geek!

Not sure I agree with this. Weight is the force exerted on a body by gravity. Aerodynamic forces are different. You're correct the car would appear to weigh more when increasing air speed in a wind tunnel. But that's from measuring the combination of gravitational forces (weight) and aerodynamic forces (downforce)!

True, hence my use of the phrase "dynamic weight" (which I probably invented to describe what I meant)

The object itself doesn't alter in weight, but the force, in kilograms, it exerts on the ground does.

Anyway, it'll look good all the same.

[Figure807]

Reviving this thread cuz I just mounted my spoiler and went for a long drive. Yes, it does make a difference, but only at 100+. At speeds below that, I really didn't notice any difference. With the spoiler the rear end felt more planted and I had less traction issues when I dropped into 4th. I used the provided mounting tape and it didn't budge even after 3+ hours of driving fast. So, if you're driving autobahn speeds, it's worth it, otherwise it's just for show