Aerodynamic weight and Vehicle weight

[soumyakd]

Was just pondering over the weights put on a F1 car i.e It creates downforce levels of 12-1300 kgs. And it has a weight of 700 apprx. Then what abt this dynamic weight added to the car (in the form of downforce) ?
Shouldnt this affect the overall weight of the car ?

I am just confused after seeing this interview of the GT-R Godfather Kazutoshi Mizuno. He being asked the reason for keeping the Gtr so heavy, replied it has the same weight as to a F1 car added with downforce !

What does this mean ?

[Cold Fussion]

Was just pondering over the weights put on a F1 car i.e It creates downforce levels of 12-1300 kgs. And it has a weight of 700 apprx. Then what abt this dynamic weight added to the car (in the form of downforce) ?
Shouldnt this affect the overall weight of the car ?

I am just confused after seeing this interview of the GT-R Godfather Kazutoshi Mizuno. He being asked the reason for keeping the Gtr so heavy, replied it has the same weight as to a F1 car added with downforce !

What does this mean ?

It's important to remember that downforce/lift is a 'pure' force, while the weight force is a result of the vehicle mass. The forces are additive, which means the total force pushing the car into the ground is the weight force + lift force. The weight force though is coupled if you will with the vehicle mass, so while increasing the mass will increase the 'downforce', you compromise all over vehicle dynamics in doing so. When you produce Lift, you get drag, however a well designed wing element will give you a lift:drag ratio much higher than 1, and if you consider an ordinary car producing lift over smaller elements (like a wing), then the percentage of the lift induced drag is small compared to the body drag of the vehicle itself, so you're effectively getting free performance.

The quote given by Kazutoshi doesn't make any sense and is borderline untruthful. If we were to apply that version of physics, supercars would look like a fully loaded lorry. The reason why the GTR is heavy is because it is cheap. Having the complex AWD system and that engine doesn't come cheap and making it cost something like half a 911 turbo means sacrifices have to take place.

[soumyakd]

Absolutely !!!
And also mizuno dint add the downforces acting on the GTr :-/ Bad

And regarding this pure force of air.
As F=ma , we r increasing the forces acting on the ground by the car but not the mass, thereby increasing performance.

Thanks mate. I got it...

[SectorOne]

Pretty sure Mizuno is joking,
And the car does not weigh because it's cheap lol. It weighs because of 4WD, lots and lots of electronics and just generally being a big car.

and contrary to popular belief, slippery as heck with a ratio of 0,27

[Cold Fussion]

Pretty sure Mizuno is joking,
And the car does not weigh because it's cheap lol. It weighs because of 4WD, lots and lots of electronics and just generally being a big car.

and contrary to popular belief, slippery as heck with a ratio of 0,27

It weighs more 200kg to a 911 turbo, and 150kg more than a R8 v10. It doesn't weigh so much more because the engineering team at Nissan is incompetent.

[thepowerofnone]

This confusion is partly a problem of the vulgarising of science: the car does not weigh 700kg at all - it has a mass of 700kg and weighs about 7000N. Weight is a force. Mass is an expression of inertia (how hard it is to make the object change from equilibrium, as given by F=m.a).

Aerodynamic lift is a force and weight is a force. Add them together and you get the force pushing the car into the road which is vital for grip. The larger this force, the more grip and traction you have.

Since the aerodynamics do not change the mass of the vehicle, you just need the mass of the stationary vehicle to tell you how quickly you will accelerate. Smaller mass = larger acceleration for a given force.

Therefore in summary: low mass is good; high downward force is good. The way to achieve this is have a really light car, and make it generate a tonne of downforce.

In truth mass is a more complicated issue than this because it also matters where your centre of mass and centre of aerodynamic loading are, but there are a couple of reasons that you might want a heavier car. 4WD is one of them.

[SectorOne]

It weighs more 200kg to a 911 turbo, and 150kg more than a R8 v10. It doesn't weigh so much more because the engineering team at Nissan is incompetent.

You know someone really doesn´t know anything when they call Nissan incompetent after they have built a truly remarkable car in the Nissan GT-R.
The goals they set for the GT-R they passed with flying colors.

The car weighs that much more because it´s twice the size of a nimble little Porsche.
It´s huge in comparison. Not because they are incompetent. Actually extremely ignorant to say that.

It´s not something new either for Nissan to set Porsche as the benchmark.
Same deal with R32 developed to match a Porsche 959. These cars are no joke on track and off track.
For the latest GT-R not many cars are faster from A to B.

[Cold Fussion]

It weighs more 200kg to a 911 turbo, and 150kg more than a R8 v10. It doesn't weigh so much more because the engineering team at Nissan is incompetent.

You know someone really doesn´t know anything when they call Nissan incompetent after they have built a truly remarkable car in the Nissan GT-R.
The goals they set for the GT-R they passed with flying colors.

The car weighs that much more because it´s twice the size of a nimble little Porsche.
It´s huge in comparison. Not because they are incompetent. Actually extremely ignorant to say that.

It´s not something new either for Nissan to set Porsche as the benchmark.
Same deal with R32 developed to match a Porsche 959. These cars are no joke on track and off track.
For the latest GT-R not many cars are faster from A to B.

I suggest you re-read my post, I didn't say the engineering team was incompetent, I said the opposite. The GTR is not a big car, I don't know why you keep harping on about it but it is not a large car, and when you look at the specs you find the it's only marginally larger.

[Greg Locock]

True, but funnily enough I read it the same way as S1, ie as a criticism of Nissan.

[andylaurence]

The GTR is not a big car, I don't know why you keep harping on about it but it is not a large car, and when you look at the specs you find the it's only marginally larger.

Yeah, barely anything in it.

[Smokes]

Nissan Set a Target weight of 400Kg per a wheel

http://suzukaracing.com/newpagegtr.html
http://suzukaracing.com/GTR%20page/racetoroadgtr.pdf

See here for more info on the aerodynamics

[SectorOne]

The GTR is not a big car, I don't know why you keep harping on about it but it is not a large car, and when you look at the specs you find the it's only marginally larger.

Go watch you average GT3 race and you´ll see just how massive the GT-R is compared to a nimble little Porsche.
You can´t just look at height width and length because a 2cm increase doesn´t sound much but in reality that´s a truckload more metal on the car.

(or you can just look at the image above. And keep in mind that a Porsche´s rear end slopes down where a GT-R goes straight)
It´s much much much more metal on a GT-R then a Porsche.

And that´s the reason why it weighs that much more. Size.

And yet, for some reason the heavy GT-R has no problems battling with a Turbo. It´s quite a feat Nissan have done.
Probably the car which defies physics the most*


*not really but a saying