Benefits from OEM chin / duck tail spoilers?

Larry Hill · 06-18-2021, 08:07 AM

I always wondered if the air deflector at the back of a wagon to help keep the back glass clean would help or hurt performance.

Jeff Stout · 06-18-2021, 09:30 AM

Quote:

Originally Posted by Larry Hill

I always wondered if the air deflector at the back of a wagon to help keep the back glass clean would help or hurt performance.

The Olds wagon is just fast enough that the deflector helps get dust off of rear window. So it does show diverting air in a forward direction.

Brad Hawk · 06-18-2021, 09:59 AM

First, I'm not one of the Hawks that the 1st poster believes me to be. Actually, my name is actually spelled H-a-a-k, but it's pronounced "Hawk' so sometimes that's how I list myself online. Ironically, I have a brother who lives very close to the track outside Boise, ID (he lives in Eagle), but he's a complete non-gearhead. I'm on the other side of the country, in the Washington, D.C. suburbs.

Some older articles I found on vehicle aerodynamics let me to believe that anything you could do to reduce the amount of air getting under the front of the car would be a good thing (ground clearance permitting), and could help with keeping the front end from lifting on the big end, too. What I wasn't sure of is whether the OEM-type chin spoilers were physically large enough to be functional in that respect, or were primarily cosmetic add-ons.

I know the ducktail spoilers do "something", but what exactly -- and under what conditions -- I'm not sure. I did find it interesting that all of the Drag Pak Challengers have come with a front air splitter, but only the latest generation of the supercharged 354 version now has the ducktail spoiler, as well.

SSDiv6 · 06-18-2021, 09:59 AM

Quote:

Originally Posted by Larry Hill

I always wondered if the air deflector at the back of a wagon to help keep the back glass clean would help or hurt performance.

Hurts performance by creating a vortex, which creates drag.

Myron Piatek · 06-18-2021, 03:28 PM

Wasn't there a discussion a while back which included first and/or second gen. Camaros trying to run the front spoiler but without the rear duck tail? Front helped while the rear hurt. Nascar shows how fractional changes on the rear makes noticeable differences in speed.

Duane Eiskant II · 06-19-2021, 07:18 PM

Just Curious if your the same BRAD Hawk that use to come by Calhoun Speed in alexandria before we closed back in 2003?

Brad Hawk · 06-19-2021, 10:34 PM

Quote:

Originally Posted by Duane Eiskant II

Just Curious if your the same BRAD Hawk that use to come by Calhoun Speed in alexandria before we closed back in 2003?

Yep. Hi Duane!

Adger Smith · 06-19-2021, 11:07 PM

Back in the early 70's when our Z-28 stocker was running high 11's we tried it with out the front spoiler and the back spoiler in place lost ET and MPH, can't remember the numbers, but with the rear spoiler off and the front spoiler on there was a + 2 MPH and about a nickel quicker ET. NHRA made us put the rear spoiler back on. What really helped was putting 6 cylinder Camaro front suspension and drum brakes on it. Hid the weight we saved in the back and the 7" tires liked it.

Brad Hawk · 06-20-2021, 01:25 PM

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

06-18-2021, 08:07 AM	#1
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,642 Likes: 1,940 Liked 10,720 Times in 2,232 Posts	Re: Benefits from OEM chin / duck tail spoilers? I always wondered if the air deflector at the back of a wagon to help keep the back glass clean would help or hurt performance. __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

06-18-2021, 09:59 AM	#3
Brad Hawk Junior Member Join Date: Nov 2009 Posts: 21 Likes: 1 Liked 2 Times in 1 Post	Re: Benefits from OEM chin / duck tail spoilers? First, I'm not one of the Hawks that the 1st poster believes me to be. Actually, my name is actually spelled H-a-a-k, but it's pronounced "Hawk' so sometimes that's how I list myself online. Ironically, I have a brother who lives very close to the track outside Boise, ID (he lives in Eagle), but he's a complete non-gearhead. I'm on the other side of the country, in the Washington, D.C. suburbs. Some older articles I found on vehicle aerodynamics let me to believe that anything you could do to reduce the amount of air getting under the front of the car would be a good thing (ground clearance permitting), and could help with keeping the front end from lifting on the big end, too. What I wasn't sure of is whether the OEM-type chin spoilers were physically large enough to be functional in that respect, or were primarily cosmetic add-ons. I know the ducktail spoilers do "something", but what exactly -- and under what conditions -- I'm not sure. I did find it interesting that all of the Drag Pak Challengers have come with a front air splitter, but only the latest generation of the supercharged 354 version now has the ducktail spoiler, as well.

06-18-2021, 03:28 PM	#5
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,542 Likes: 34 Liked 138 Times in 51 Posts	Re: Benefits from OEM chin / duck tail spoilers? Wasn't there a discussion a while back which included first and/or second gen. Camaros trying to run the front spoiler but without the rear duck tail? Front helped while the rear hurt. Nascar shows how fractional changes on the rear makes noticeable differences in speed. __________________ LOCOMOTION Racing

06-19-2021, 07:18 PM	#6
Duane Eiskant II Senior Member Join Date: Dec 2001 Location: Alexandria, Va Posts: 501 Likes: 261 Liked 57 Times in 33 Posts	Re: Benefits from OEM chin / duck tail spoilers? Just Curious if your the same BRAD Hawk that use to come by Calhoun Speed in alexandria before we closed back in 2003? __________________ Duane Eiskant 1354 Stock/Super Stock

06-19-2021, 11:07 PM	#8
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Benefits from OEM chin / duck tail spoilers? Back in the early 70's when our Z-28 stocker was running high 11's we tried it with out the front spoiler and the back spoiler in place lost ET and MPH, can't remember the numbers, but with the rear spoiler off and the front spoiler on there was a + 2 MPH and about a nickel quicker ET. NHRA made us put the rear spoiler back on. What really helped was putting 6 cylinder Camaro front suspension and drum brakes on it. Hid the weight we saved in the back and the 7" tires liked it. __________________ Adger Smith (Former SS)

06-20-2021, 01:25 PM	#9
Brad Hawk Junior Member Join Date: Nov 2009 Posts: 21 Likes: 1 Liked 2 Times in 1 Post	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 Last edited by Brad Hawk; 06-20-2021 at 01:29 PM.