Are rear spoilers effective or just for show?
 

Hi:

I own a 99 C5 FRC and am going to do some bodywork to the car and am considering adding a small rear spoiler. I don't want to add a full wing. My question is whether the spoilers available on the market are functional and add down force thus making the car grip better or are they mainly just "drag generators" that look good but have no real functional benefit?

I would appreciate it if anyone has some test data that can comment and provide some guidance and what brand style you would suggest if there is benefit?

My car has several mods (CCW 18" classic wheels & performance tires, lowering springs & Bilsteins, Hotchkiss sway bars/end links, TPIS Cam, long tube headers, and full intake/throttle body/exhaust, etc.) in other words she is fast and handles well. I take the car to BIR in Minnesota once or twice per year just for fun. I like the look of a small rear spoiler but since the car feels very balanced and handles well on the track I don't want to add a spoiler if doesn't add a performance advantage in terms of high speed down force and just creates more drag which will ultimately slow it down.

Thanks!

Tom

Do a search in the Road Race Autocross section. You can find some good info there from people who really know. Search "Aero".

not sure what data i can provide that isnt documented to death. downforce is downforce. saying it "feels" this or that doesnt help, and lap times can vary wildly.

unless you mean those tiny little tail "spoilers" which are 100% aesthetic. only do that if you like how it looks. i dont give a sh** what any old man with 50 different bookmarks on the best polishing techniques thinks about my car.. it's a form follows function build!

https://cimg7.ibsrv.net/gimg/www.cor...962af60bd1.png

speaking of rear aero here only, you'd have to counter it with front aero. dont have a good shot of it on the car yet, but have one of putting it on. you'll want hood vents + splitter if you go with a full true "wing" spoiler. im going to swap to the Eckler's style front fascia and bolt this splitter to that, and add the full under-car flat bottom. once you do any of these, it's kind of an all or nothing street if you care about balance.

a few vendors/options are in this thread:
https://www.corvetteforum.com/forums...-from-acp.html

https://cimg2.ibsrv.net/gimg/www.cor...cb1e817563.png

If you are going to get a rear wing, do it the right way and get one that bolts/welds to the frame of the car.

https://cimg5.ibsrv.net/gimg/www.cor...a9c68eae73.jpg
i added brackets so that its held against the frame. if you cant do basic welding, undertaking this much modifying might not be the best idea. i carved this car like a pumpkin. that little trunk in the rear? yea i cut that out and glassed it back in upside down to make room for the new rear aero, haha. poor car.

i put the stereo in so i could listen to music in the garage. just moved and my bluetooth kept dying, so thats not normally there, either.

If you want to find out if your rear spoiler is functional or a dress up kit you can easily tell be going don the highway at 70 mph and check the DIC for you gas mileage. If you normally see 28 mpg on the display and then add a rear spoiler and it says 22-24 mpg then it is effective. I have a few friends with the flat panel spoiler and they do not see any difference. When I run Street Prepared and drive the Corvette to a local event with the spoiler I never see more than 24 on the display and normally I will see 29-30.

For track work, a big spoiler plus other aero does the job. For a road car, not so much - they are mainly for looks as they really don''t do much at legal speeds. And giant wings on road cars are so ricer.

heh, good point. i havent put it on the street enough to know, but ill run some with and without tests for a 10 mile stretch and report back here one day. for science!

but on that note, any wing worth a damn will have adjustable angles of attack. going out at autocross it's basically a vertical sail. going to a fast track, it's not doing much til ~70 mph.

I'm no aero expert and thus anything I may say could be contrived as hearsay but you're putting yourself behind the 8 ball a bit having an FRC and seeking lower profile aero. If there would be any sort of aero advantage gained with an FRC you would need a spoiler that jettisons further up into the air; preferably it needs to sit higher than the roof line. Even the factory Corvette enduro team didn't use the FRC/Z06 body in their racing efforts.

If you're concerned about looks away from the track, one thing you may look into as someone mentioned above is mounting spoiler stands directly into the frame through say the license plate garnish. Not only would this allow you to remove the spoiler away from track days but it would place the spoiler further behind the rearmost point of the body line and thus take better advantage of air. You could simply remove the license plate and reverse garnish plate at the track, mount the spoiler, go about your business, and remove it when it's time to go home.

If you want to learn about having aero on a C5 FRC, you should contact Danny Kellermeyer at DJRACE.com.

Where did you get this rear valance / splitter?

I know this is older but holy shit how do you get into your trunk?

I know this thread is a bit of a zombie, but I figured I'd pass along probably the best spoiler kit I've seen. This is a great option for both track and CAM-S Autocross because it is quickly interchangeable between the autocross duck bill and a proper track wing.

The only downside is you need to cut your rear bumper cover to make it work. Fortunately I have a spare!

How are those ricer or race spoilers on corvettes and who uses them on their daily driver? I was looking into spoiler kings stuff but i see the classic universal wing is an option just not sure how it would look.

It really depends on how it's mounted as to whether it's "ricer" or "racer". If it attaches with double-sided tape or any other adhesive, it's guaranteed to be rice. If it bolts to the body, there's a good chance it's rice, but not for sure. There are a few exceptions, like the yellow car posted above where the owner internally braced the spoiler under the body panels.

A proper race spoiler will be mounted to the chassis, usually through the rear bumper cover. Effectiveness depends on a lot of variables, not the least of which is balance. If you put a ton of rear downforce on a car via a spoiler, but none on the front, all you're doing is lifting the front of the car and taking weight off the front wheels. If you're running a wing at 0 AOA, it's pretty much all for show unless you've got big side plates giving lateral stability, etc.

Yes i was referring to the universal spoilers that they use on mostly 4 cylinders but are seen on the c5r in gran turismo.The ones specifically for c5 corvettes are 600-1200$ i seen in carbon fiber or whichever may be better to find the universal.

I have the original design of that spoiler that JCG Restorations did. I believe that Ryan from After Dark Speed just tweaked the design a little bit and started to sell them. They are fantastic!
https://cimg9.ibsrv.net/gimg/www.cor...426c4a0fa5.jpg

What splitter is that, and how is it attached? Any issues with the cooling system?

Anyone know where the rear diffuser from jdmvette came from?