Belgian1979vette

Does anyone have these numbers for a C3 ?

thanks

gbvette62

I don't recall that exact coefficient of drag numbers. I do remember that the redesigned 80 nose, with it's integrated front spoiler, reduced the cd about 12 percent. I think Corvette News claimed at the time, that the cd was something like .440 for the 80-82's, verse .500 for the 79 and earlier nose.

On average, the 68-82 has the smallest frontal area of all Corvettes, at around 19.3. I think the 84-96's are about the same, with the 53-67 and 97 and up cars, all being over 20.

Richard454

Here's a good read-

http://www.superchevy.com/how-to/cor...g/viewall.html

Belgian1979vette

Can't seem to get any good info, besides the frontal area being 19.20 sqft and the drag coefficient 0.44.

BKbroiler

That's the information you asked for.

gkull

I wouldn't call that a good read. C-3 Vettes need to be split into 2 and maybe into three groups. chrome bumper, flex bumpers, and finally the most earo are the 78 with front spoiler and rounded rear window through the 82.

ddawson

I have an RX7 and one of the guys has access to a water based drag system and he was doing pop up head lights.

He didn't do a test though of the C3.


At 6.50 he starts with a chart showing drag with lights up or down. BTW the C3 is the worst.

The whole video is great though.

Torqued Off

Fancy smoke video....so what does it prove?

ddawson

LOL that pop up headlights have a large effect on aerodynamics.

Here is another where he shows how adding a spoiler effects rear lift.

Belgian1979vette

I have the 79 with the front an rear pace car spoiler. So the advertised values are probably nowhere correct.

gkull

If you can find an old motor trend article or road and track from around 1979 they always did road tests with CD rating

Belgian1979vette

pre-digital era ? Since i'm on the other side of the pond there will be slim chance on it.

Would it be anywhere near an 82 ?

TheSkunkWorks

FWIW, I recall seeing published factory claims back in the day that the PC aero kit reduced the '78-79 body's CD by as much as 15%. So, yes, the standard CD numbers for those years without the aero kit would be off by a significant margin for those of us with the kit. And, yes, that would tend to put the '78-79 w/PC body fairly close to the '80-82, tho I've seen well founded arguments that the latter is the more slippery of the two when it comes to absolute drag numbers.

And, although the OE front dam could use some additional support for such use IMHO, tho I have no downforce data/calculations to site as of the moment, according to the sensitive instrument on which I sit installing the PC kit and lowering to Chevy Power heights definitely improves high-speed (100+ MPH) stability by a good bit. I would suspect, although likely a touch less aerodynamic from a purely CD perspective, that the '78-79 w/PC kit might have slightly better lift/downforce numbers, at least at the rear due to the larger spoiler. ...a fair trade in my book when your more worried about being glued to the road than MPG. My $.02, HTH.

Bad Bird

No, C2 is the worst when you look at it all. So much lift!

U17

There is a graph out there ... all generations... headlights up and down... I have it but for some reason I can't copy and paste.... but it's there ....

TheSkunkWorks

I thought about that chart and searched it up last night myself, but saw upon review that it makes no allowances for significant variations within our generation - particularly regarding the PC aero kit.

RickyBerg

Can anyone say how much the resistance trough the air increases with speed?

If a car travels in 60 mile/hr the drag may not mean so much, so how much will it mean if one double the speed?

Is there a calculation in how much HP it will take to travel a given resistance in a given speed?

I don't believe that most of our old Vettes will have any problems with stability in 120 mile/hr give that the chassis are in good condition so most of us may not need to worry about lift forces etc.

My car for example tops out at 145 mile/hr at 6000rpm and i have no need of going any faster due to the length of the straights we have on the tracks here in Sweden.
But may i have something to gain in acceleration from ex 60 to top-speed if i did some modifications on my car?

I have seen on this forum that some block of the front grills with perplex (transparent plastic) and would that give me some noticeable improvement?

Am I stealing someone else thread now..?

//Ricky.

metal tech

Vette or Corvette magazine did a wind tunnel eval on Vettes back in 09 I think, I can't find my copy. They used the wind tunnel in/near Charlotte NC to do the test. It had lift and downforce figures from C2/3/4/5/6 cars that owners lent them for the test. From what I remember, the HP requirement to double your speed is 4x, and that HP is dependant on the aero slickness on the vehicle in question.

BKbroiler

That is correct. Talking strictly about wind resistance, it takes 4 times as much power to push a car through the air when the speed was doubled. Because, over a given time period, you're pushing twice as much air, twice as hard (creating a bigger "wake").

69427

Aero drag increases as the square of the speed (four times the drag at twice your 60 mph example). The horsepower increases at the third power (eight times the horsepower at twice the ground/wind speed).

I blocked off my outer and license plate grilles, along with about 50% of the undergrill openings to reduce the amount of air going through and under the car. No overheating issues yet.