Steve Rea

iTrader: (1)

That's it...just how effective are they?

Do they provide any significant downforce?

or do they simply break up the airflow so that the low pressure is further back from the rear of the car, therefore avoiding a parachute effect?

Thanks,

Steve

gnx7

iTrader: (28)

You are kidding right? of course they work. Every single race car that is allowed one puts the largest one they can within the limits of the rules.

They provide downforce on the car to keep it planted at high speeds. Rear spoilers really don't do much under 75mph. For road racing on a high speed car they make a cart stable and able to negotiate turns at much faster speeds.

Low spoilers that have little angle to them and are on the decklid don't do much vs raised high profile ones with legs that really work. Do a google search... there must be thousands of pages you can reference.

Cal

iTrader: (1)

As stated above, a lot of of how they work depends on the speed you are going. The higher the speed, the more down force they provide. As speed keeps increasing, it is possible at some point that a given spoiler will actually push too hard on the rear of the car and start to take weight off the front end. Dedicated race cars have an adjustment that allows the spoiler to be set to the correct angle for the speed they will race at, and they use a digital protractor to measure the angle to the nearest tenth of a degree.

mitchntx

iTrader: (14)

Go pick up a copy of this month's Hot Rod magazine.

There is a pretty good aero primer on how it ALL works as a package ...

TTSSZ

iTrader: (8)

I just read that the low z28 spoiler in my 71 gives 120lbs of LIFT at hi speed!
that aint good.............

The high spoiler that came on the 72 and 73 z28 gives something like 140lb of down force at speed.

RICRH8R

Rear spoilers are very effective if they have airflow above and below the airfoil. Factory spoilers are more look than effect. But if you want an effective aero pakage you need a front splitter or chin spoiler to create downforce on the front and also to create a better low pressure area under the car (a slight rake improves this as well). I know some companies make them for the camaro and the vette (http://www.lgmotorsports.com/shop/pr...cb0522a47ad36). If someone can find one for a 98+ t/a post it or im gonna have to make my own.

all in all
Rear Downforce > Front Downforce, car becomes bad airplane

Gnx7 makes a good point

DONAIMIAN

iTrader: (18)

I can really picture a 95+(or whever they started using the highprofile wing) with a taller rear wing. I think anything higher than 1.5-2 inches would start to look goofy.

Steve Rea

iTrader: (1)

Please understand that when I refer to a "spoiler" (nascar style) it is not a "wing" (which has an air-foil). The reason I ask is that it would be a very simple aero mod and much less expensive than a proper rear wing.

Absolutely the rear aerodynamics will need to be balanced with the front. We have many options we can use to balance the front downforce with the rear: splitter, whiskers, hood fences, hood vents, front fender top venting.

I was curious how effective the nascar style spoilers would be in road racing.

Steve

Jon A

They can be quite effective. Some good reading:

Steve Rea

iTrader: (1)

Great info John! Thanks, it was very interesting, as I hadn't thought about how it would increase the pressure over the rear trunk or area behind the roof, where there is the low pressure area, thereby reducing lift. Very interesting, as I had only considered how it affected the airflow's effect on the car as it passed over the back end.

Thanks,

Steve

erikerikerik

True story

JackZ28

Mine works good!

300bhp/ton

I think you are confuding spoilers with wings. Very similar but subtly very different.

Spoilers
Spoilers are used primarily on sedan-type race cars. They act like barriers to air flow, in order to build up higher air pressure in front of the spoiler. This is useful, because as mentioned previously, a sedan car tends to become "Light" in the rear end as the low pressure area above the trunk lifts the rear end of the car.

Front air dams are also a form of spoiler, only their purpose is to restrict the air flow from going under the car.

Wings
Probably the most popular form of aerodynamic aid is the wing. Wings perform very efficiently, generating lots of down force for a small penalty in drag. Spoiler are not nearly as efficient, but because of their practicality and simplicity, spoilers are used a lot on sedans.

The wing works by differentiating pressure on the top and bottom surface of the wing. As mentioned previously, the higher the speed of a given volume of air, the lower the pressure of that air, and vice-versa. What a wing does is make the air passing under it travel a larger distance than the air passing over it (in race car applications). Because air molecules approaching the leading edge of the wing are forced to separate, some going over the top of the wing, and some going under the bottom, they are forced to travel differing distances in order to "Meet up" again at the trailing edge of the wing. This is part of Bernoulli's theory.

What happens is that the lower pressure area under the wing allows the higher pressure area above the wing to "push" down on the wing, and hence the car it's mounted to.

Wings, by their design require that there be no obstruction between the bottom of the wing and the road surface, for them to be most effective. So mounting a wing above a trunk lid limits the effectiveness.

6SpeedWS6Formula

Does anyone know how much of a difference the Formula vs. T/A spoiler is? I've heard the ones on the Formula are more effective, but didn't think to ask in which way, creating drag or reducing? It depends on how you look at it you know, if I only care about speed I want less downforce so to me that would be "more effective". Does anyone have numbers on the two spoilers?