Ducktail Vs. Carrera tea tray?

[targa871]

Hi. I have a 1987 targa with a factory carrera tail & was thinking about going with a ducktail. The more I see these tails, the more I like it. My question is, what are the pros & cons of the duck tail. Is there less cooling benefit? Will down force at speed be less? I do about 3-4 DE days each summer and was wondering if a ducktail will be a problem. Thanks in advance for your help.

[Wil Ferch]

Officially...according to Porsche published data at the time....the Carrera orTurbo tails ( either one) was a bit more effective than the Duck. That said, in practical terms, one would be hard pressed to really feel the difference of these 3 tails unless all your experience is all on the track at over 90-100 mph. Most likely the Turbo was most effective of the 3 styles.

Likewise, Porsche data of the time showed a lowering of engine temps of about 10 degF when using any tail over "none".

[rusnak]

You could just get a second decklid, and change them over for track events. Doesn't take too long.

[KTL]

I switched from a Carrera tail to a ducktail and still went fast. Like Wil said, I think the differences are hard to quantify on our cars at the speeds we typically see on the track. Unless you're at a fast track with high speed sweepers, I doubt you'll truly feel a distinct difference.

Cooling is fine with a ducktail. Think about these couple of aspects

>The cars without Carrera tails (just a plain deck lid) cool just fine

>The opening in the Carrera lid is the same as the plain lid, except the tail has a larger surface area & more slats to capture cooling air.

[JeremyD]

Shakinjoe's 1987 with a duck

[RoninLB]

i'd say that if you're on 2 lane roads at speed and a big rig with its trailer passes the other way a duck may not be enough to keep your car planted like the Carrera tail can? Without anything the car gets thrown around

i have the C-2 electric spoiler which i haven't really tested yet under those circumstances or i'd have more info. For sure i wouldn't sell the Carrera tail until i was sure the duck was ok

all this also assumes you have the Carrera front spoiler

[Wil Ferch]

Indeed you should balance the car with a front spoiler. RoninLB.....I agree the lack of a tail has some negative aero drawbacks, IIRC the Porsche tests show net 300 lbs rear end lift w/o a tail ( at 150 mph !!! ),..... reduced to maybe 100 lbs net lift on the car's rear with any of the tails. The duck was the worst of the 3 but not by much. I'm sure the graphs were posted in Pelican somewhere.

[drl911]

Here's the chart. And FWIW I went from factory tail to ducktail (liked the look) and now back to fiberglass whale tail for more stability AND less drag on the back straight at Road Atlanta during DE's (~125mph).

[targa871]

Thanks for all the info. Yes I have the front spoiler on the car. I'm glad to hear that cooling will not be affected. BTW, I am deleting the rear bumper pads and corner stips. I'm trying to clean up the look.

[RoninLB]

those wheels and tires are Loud

[KTL]

Simmons wheels rock. Made in Austrailia down unda.

[Wil Ferch]

FWIW...when it comes to the graph...."3.3 Turbo" means the high-on-all-3-sides Turbo tail that we all know about. The graph label "Turbo" means " early Turbo"..... much like the Carrera tail, with only an upflip at the backside.

[agrimmitt]

I have a couple of tails I change as needed. The Ducktail is the classic (original look) tail and work well, but my IROC has a hold lot more down force at speed. Both are reproduction tails made using factory metal decklids. And I owned a 76 Turbo Carrara new and don't like the rubber portion of (any) the tails and thats another issue in time. I have had more than a couple complete fiberglass units and all in time have some type of issue. Cost a little more, but a one time expense to have it right. Questions, (send and me an email>or call Gary) check my Garage; both were custom made for me by Gary Stratton in Florida.
art
agrimmitt@pelican

[daniel911T]

Simply my opinion.... The duck is by far the best looking, but it belongs on a longhood with chrome.

The later, blacked out, shorthoods look much more modern, and the Carrera and whale tales look much better on them.

According to the posted chart, if you're doing any racing you're going to get better aerodynamics with the later, larger tails.

Cheers!

-Dan

[Thrasher]

I think that graph may have come out of The 911 Story. I don't have the book handy, but what about drag of the Duck vs. Carrera/Early Turbo (non tea tray)? IIRC, Frere says overall Cd drops with the tails (vs. none) but I can't recall about diffs between tails.

I added a Carrera tail and front lip and could immediately feel the stability differences, but was thinking to shed some weight a fiberglass decklid with Duck would be the best compromise of weight loss with only minimal downforce loss.

Anyone know the drag numbers for each?

[Wil Ferch]

Thrasher.

....don't have the resultant drag numbers handy but maybe if I dig I can find. All the tails should improve drag numbers....IIRC. A good index would be the resulting Cd drag coefficient..and I believe it drops from 0.41 to high 0.3X numbers when using any of the tails.

I agree on weight...don't want it up-high-and-back on a 911. FWIW....I have a very nice Getty/Shaw RSA tail ( like Carrera tail, but w/o wiper hole) in "all -glass"....but my projects took another direction. MUCH lighter than stock Carrera base and rubber surround. I'm guessing maybe 6 lbs. If interested, please PM me and we can talk a possible deal.

[Bill Verburg]

Originally Posted by Thrasher

I think that graph may have come out of The 911 Story. I don't have the book handy, but what about drag of the Duck vs. Carrera/Early Turbo (non tea tray)? IIRC, Frere says overall Cd drops with the tails (vs. none) but I can't recall about diffs between tails.

I added a Carrera tail and front lip and could immediately feel the stability differences, but was thinking to shed some weight a fiberglass decklid with Duck would be the best compromise of weight loss with only minimal downforce loss.

Anyone know the drag numbers for each?

As far as I know I originally posted that graph years ago. It is from a fellow by the name of Robert White, he did an engineering internship at Weissach in 1977 and did a presentation on it at the Warbonnet, it was later reproduced in Pano on several occasions. I believe that Frere also published the same graph, I'm sure they both got it from the same source. There is an accompanying graph for the front end too

[Flieger]

Originally Posted by Thrasher

I think that graph may have come out of The 911 Story. I don't have the book handy, but what about drag of the Duck vs. Carrera/Early Turbo (non tea tray)? IIRC, Frere says overall Cd drops with the tails (vs. none) but I can't recall about diffs between tails.

I added a Carrera tail and front lip and could immediately feel the stability differences, but was thinking to shed some weight a fiberglass decklid with Duck would be the best compromise of weight loss with only minimal downforce loss.

Anyone know the drag numbers for each?

IROC tail + front IROC with splitter.

[Bill Verburg]

Originally Posted by Thrasher

....
Anyone know the drag numbers for each?

here

[RWebb]

graphs were also reproduced in one of the UpFixin' volumes