downforce? please read

[Mshkttck]

What's the difference between downforce and weight? I understand that spoilers create downforce on your vehicle, but how is that different from putting weights on your car? Couldn't you just slap heavy sandbags on to your car and get the same results as a spoiler?

Please reply!

[timberdoodle]

basically yeah. Spoliers and such are placed in locations that are beneficial to the car's handling and getting power to the pavement. All they do is force (for example) the rear of the car down at higher speeds so it is more stable and the tires stay down on the road better. Basically, you could do the same thing with sand bags i suppose but you would increase the overall weight of your car defeating the purpose. Those wings dont really do anything though that you see on imports and regular cars. You have to be going hella fast to get much downforce.

[beef_bourito]

ya, pretty much the only cars that do are f-1, funnycars, etc. the ones that go about 180mph

[Mshkttck]

Originally Posted by timberdoodle

basically yeah. Spoliers and such are placed in locations that are beneficial to the car's handling and getting power to the pavement. All they do is force (for example) the rear of the car down at higher speeds so it is more stable and the tires stay down on the road better. Basically, you could do the same thing with sand bags i suppose but you would increase the overall weight of your car defeating the purpose. Those wings dont really do anything though that you see on imports and regular cars. You have to be going hella fast to get much downforce.

So weights would produce more traction than a spoiler at low speeds? Than why has nobody tried to do that in autocross or rally? Stress on the suspension or something?

[beef_bourito]

Originally Posted by Mshkttck

So weights would produce more traction than a spoiler at low speeds? Than why has nobody tried to do that in autocross or rally? Stress on the suspension or something?

because the weight produce more weight. when a car is heavier, it accelerates slower and is more difficult to handle, you want a lighter car when you race.

[Mshkttck]

Oh, I see, so the momentum of the car would make the extra mass harder to accellerate and deaccelerate, wheras the spoiler would decrease and increase the amount of downforce depending on the speed? Thanks.

[Auto_newb]

The other thing about weight is that it shifts, downforce just pushes down a car according to it's shape giving more grip to the tires are high speeds

[Nexagen]

All I got to say is...

If your cat does not have 300+ HP

a spoiler is kinda useless...

If u have 110 Hp on your honda and u got a spoiler... ::Cough:: Ricer! ::Cough::

Who the hell are u kidding?

U really think u are going to get downforce at 30 miles per hour?

No... downforce begins at least at 120 MPH for it to actually kick in.

Otherwise it's just useless.

[BeEfCaKe]

So you're saying if i had a 300hp civic, I should strap on a spoiler? I don' think so. Its the fact that civics are FWD that makes spoilers almost useless, of course there are a few exceptions, but I'm just saying in general.

Additionally though, you don't need 300+ Hp to do 120mph. So i think you're kind of contradicting yourself.

[replicant_008]

Okay, quick physics lesson 101

E = MV

Energy = Mass x Velocity

Therefore you need to use more energy to get a heavier mass to the same speed than a lighter mass. Therefore, for a given amount of engine power, a lighter car will accelerate faster all other things being equal. It will also brake faster and be more nimble. It won't work its brakes as hard nor will use as much fuel... weight also got this property of inertia. If you instance stuck a pile of ballast in the rear bumper then yes it would help your initial traction but in a high speed lane change you could end with it acting like a pendulum and flinging the car into a spin (don't laugh ask any 911 or original Beetle owner what the pendulum effect is in a rear engine car).

And to be honest, I know a lot of rear-engine rally car drivers who put bags of cement over their rear axles to aid traction in years past.

Now that assumes all things remain equal - which they don't.

Mechanical grip is the relationship your tires have with the road surface. The more grip you have - the better you are able to take the energy of the engine and use it create motion - lest you end up wheelspinning. Which to some looks spectacular and is the stuff of pubescent boys wet dreams but is basically wasted power. If you have better grip then traction allows you to use more throttle off the line and accelerate better.

Grip is another double edged sword - wider tires give better grip but induce more drag. Adding weight increases initial mechanical group but you pay in the extra energy once initial traction difficulties are overcome and grip becomes less crucial to acceleration.

When it comes to cornering, you tend to want to have more grip the faster you go.

Aero aids add a relatively small amount of weight but add a fair bit of extra mechanical grip once a certain speed is reached. This again is compromised by the additional drag of the aids. Also during acceleration in a straight line - grip is less of an issue and at high speed aero aids can limit top speed. On the other hand, aero aids can add stability (witness the retro fit of the boot spoiler to Audi TTs after high speed stability issues).

Now 'downforce' can be achieved a number of ways. You can stick to a big spoiler which adds a lot of drag and depending on your suspension setting will compress your springs more than adding downforce. Or you can stick a big front splitter to reduce 'lift' or use a sloping aero underbody with venturis to reduce drag and produce downforce.

Some folk will tell you that 'downforce' doesn't happen to super high speeds... now that's true but reducing lift and improving stability can happen at relatively low speeds (and reducing drag too)... and the aids can be quite subtle...

The main issue with wings on imports etc are they are crap. For their size they don't actually produce much effect and are usually for styling purposes. If you look on the trailing surface of the trunk of a current BMW M5 you'll see a subtle kick in the surface. That very subtle and discreet little spoiler actually has a significant effect on the high speed stability.

Trouble with a lot of the wings for road speeds is that if you went down to the library and got manuals on NACA profiles for the speed range you'd end up with something that would look quarter of a oil drum with slotted holes drilled 3/4s of the way up with end plates. Doesn't look very nice at all and not a lot like the wings you see with less transition that are used in race cars - and would produce a lot of drag at higher speeds.

You could go for an aero aid with moveable surfaces but you add weight and complexity.

Trust me buy wider tires, upgrade springs and shocks and get more power!

[83-944]

"No... downforce begins at least at 120 MPH for it to actually kick in."

PROVE IT. Back your claim up. You're full of it and i can back my claim.

It's odd that I had a 110HP Neon that could do 120MPH A spoiler wasn't necessary at all. It sure as hell needed a splitter in the front, but no wing.

[CrzyMR2T]

spoilers can work at highway speeds, it doesnt matter if you have fwd, it will still be effective. most cars that come with spoilers from the factory do work, you dont have to go over 100 mph for it work. lots of car companies have done tests to see how spoilers effect a cars stability at highway speeds, and found it to be quite effective, there were noticeable differences.

[ales]

Also don't confuse the spoiler and the wing, the differences have been discussed in this forum several times before.

[Auto_newb]

"No... downforce begins at least at 120 MPH for it to actually kick in."

PROVE IT. Back your claim up. You're full of it and i can back my claim.

It's odd that I had a 110HP Neon that could do 120MPH A spoiler wasn't necessary at all. It sure as hell needed a splitter in the front, but no wing.

I agree, if they think it has to be high speed, they should stick their head out the window at 50 k's, plus the spoiler/wing (I dunno the difference) has a larger surface area than your head so think how the spoiler would be effected....



I also agree it is quite useless on a FWD car, I just can't find a reason how it would be better to have a bigger tendency to lift up the front end...

[Reed]

the problem here is that i think most people who buy a wing are drag racing far more than they are road racing. for drag racing the wings are kind useless unless you are breaking 100mph by the end of the 1/4 mile, they are just producing drag. if your drag racing only get a spoiler (if you have a fwd car) if you feel your car getting all squirly by the end.

now if you are doing more road racing and are concerned with handling then you might want to get a wing (even in a fwd car cause you may set up your suspension to oversteer).

i dont have time right now