Re: Benefits from OEM chin / duck tail spoilers?
 

I found some screenshots of an old Car Life magazine test of OEM front & rear spoilers & wings that touched on this topic. Unfortunately, I can't get the png copies I made of sections of the article to upload successfully here and I don't know what's causing the error.

The brief summary of the pertinent data was that for a '69 Camaro Z-28 tested with no OEM spoilers, front chin spoiler only, rear ducktail spoiler only, and both spoilers. The test data was taken at 65, 85 and 115 MPH intervals using equipment that at the time appeared pretty state-of-the-art, but archaic compared to what's available today. My interpretation of the graphs is as follows, with "+" indicating lift in lbs and "-" indicating downforce in lbs from the 115 MPH measurements only

No spoilers: F = +370; R = -25
Front only: F = +220; R = -30
Rear only: F = +400; R = -120
Both F&R: F = +325; R = -140

I came across some anecdotes from "way back when" that some class racers had dome similar tests on the track and found small improvements with running only the front were cancelled out by running the rear, too (just like A. Smith mentioned above), but the NHRA was being hardliners about having to run both, if the factory option package was specifically for both pieces.

What I see today looking at a couple of A & B/SA '70-71 Challengers is cars that are using these OEM add-ons aren't necessarily doing it as a set (e.g., one A/SA car has only the front chin spoilers and another B/SA car appears to have only the ducktail spoiler), so I don't know if that rule is even enforced any longer. Or maybe the Mopar options were more flexible than the Chevrolet.

I don't know if any of this is still pertinent to what's being run today, but I'm certainly curious. Thx

EDIT: It looks like the original article is posted in screenshots on this older Moparts.com thread, if you're interested in seeing more of what it involved: https://board.moparts.org/ubbthreads...unctional.html