Last C5

Do the small spoilers like the SLP, Caravaggio, etc. provide any down force for a C5 or are they just for show and tell??

AU N EGL

think I read some place that the rear spoilers should be pointed up at 45* or greater to be of any effect.

davidfarmer

I think they help, but wings are more effective and efficient.

John Shiels

nascar

they won't usually hurt but I doubt you will feel anything.

PeOR

I found this very informative.

http://www.katechengines.com/street_...a%20report.pdf

PeO.

GettReal

I have the Caravaggio front canards and rear spoiler and was told, as David mentioned "it helps" reduce some lift but they don't create a lot of downforce. I had the front canards moulded in so its one piece.

I got these for the looks back in my waxer days but happy if they help a bit on the track

John Shiels

no clue on what they are saying with configuration #1

rear spoiler added a bit of front down-force and then 7X what?

z06801

Should these be removed when a wing is added?

GettReal

I have seen two different cars on here that have the Caravaggio rear spoiler and also a wing.

VGLNTE1

C6r keepa the zr1 stock spoiler plus the wing. I highly doubt those stuck on pieces do anything other than look cool

AU N EGL

have seen more then a few double sticky taped on spoilers come off at speed.

One front splitter too. car it was stuck and too much down force and ripped it off the front facia . car drove over it too at 120 or mph.

Socalrebell

I can't answer your question I do not road race my C3, but I do road race a Viper ACR and you definitely can feel the difference in the front canards & splitter but the real biggie is in the rear wing. Gives you 1,000 lbs. of down force at 150 mph.





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Everett Ogilvie

Canards (dive planes) work and they are on race cars for a reason;

Socalrebell

For a rear wing to work properly it must be at least or close to the height of your roof, that's why they do so much wind tunnel time. Those "aesthetic" wings are for looks not function.





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z06801

I know mine won't come off, fact I dread taking it off if I have too, went a little overboard putting it on I was just wondering if it disturbed the air enough to make the wing not be as efficient.

VGLNTE1

I love the ACR

Everett Ogilvie

I am not quite sure which wings you are referring to as "aesthetic" ones - surely you are not saying the wings on the Mosler race cars are aesthetic? Really? That Mosler picture is a real race car in a real race, with the wings on all the cars mounted according to the regulations of the sanctioning body. If you really think that wing height is so simple, study any aero engineering book which shows many examples of wings GAINING downforce as they approach the deck on race cars (see my post below with data, not conjecture), especially ones shaped like Daytona Prototypes (and Moslers) with narrow cockpits which disturb the air feed to the wing far less than ACRs and Corvettes.

John Shiels

cleanest air is when the wing is higher and farthest back. That is where it will work best. I actually moved my wing up two inches and made some aluminum canards. Two screws and the canards are off so easy to see if I can feel a difference or see it in lap times. I forgot but the wing is at least level with the roof top. No idea when I will test it due to business and desire. Hopefully I finish the rear of the car in the next few weeks.

Uprights on the Viper above have less drag than a solid one piece upright.

Everett Ogilvie

Respectfully John, it is not that simple.

First, FIA regulations typically mandate for many classes that the wing is 100mm below the roof height, but far more importantly, the literature shows that optimum wing height is a function of a percentage of wing chord, AND body shape (my earlier reference to the wings on Daytona Prototypes, Moslers etc which have narrower cockpits - the wing is in less disturbed air, and they have long rear decks - the cockpit is not right in front of the wing like on the Viper and Corvette). So again, the body shape and the wing chord dictate optimal wing height for any given car, and it is typically .5 to .7 of the wing chord (these references are from McBeath, Competition Car Aerodynamics, and he is referencing Katz, Race Car Aerodynamics).

"And a single element wing on a sedan-based racecar showed best vehicle downforce when at about 0.7 of its chord above the rear deck, again with downforce reducing at higher or lower positions."




This data below is for a Lotus race car with a wing of chord 230mm -
"downforce increased with wing height until its height was slightly greater than its own chord dimension, the gain then appearing to flatten off." (and again the rules for most classes specify the wing must be some minimal distance below the roof height)




Of special interest is the fact that if a wing is mounted too high it can reduce the interaction with the diffuser (if the car has a real, functioning diffuser). Katz' data shows with some body shapes and diffusers, reduced wing height increases the efficiency of the diffuser, increasing downforce (I will post that data later). For the case of the Lotus above, they found that the diffuser was not functioning as well as it should have been due to the positioning of the exhaust, so they theorized with a properly functioning diffuser a lower wing height (than the full chord length) might have been optimal.

Bottom line, you can't generalize ANYthing about aero from car to car.

As promised, here is Katz' data (from Race Car Aerodynamics) for a prototype race car showing that as the rear wing moves closer to the deck downforce increases, until the wing is about 0.5 wing chord above the deck (meaning if your wing is 11'' in width it will have max downforce when mounted about 5 or 6 inches above the deck - ON THIS TYPE OF CAR. Note, this body shape is identical to a Mosler....

Painrace

Call Jason at Katech and he will help you understand the numbers.

Jim