John G.

I'll look into the front bias in the ride height. I recently had the car lowered somewhat and need to look at the exact measurements of the front vs. rear.

The reason I'd prefer a ducktail is to keep the somewhat "retro" look to the car. I mostly see 911s with some sort of large whale-tail and very few (if ever) with a ducktail. I've no real intentions of treating the '77 like a autobahn rocket and cruise at 100, just getting up there once in a while.

So I guess, in the end, what I'm really asking here is: "Is there ANY noticable improvement in ride quality with a ducktail on a targa." And I don't really want to add a whale- or tea-tray...

-JG

1977 911S Targa

Edgy01

I have to agree with you that the narrow-body 91s look a bit out of place with a whaletail so the ducktail is a beter option. Yes. You will feel a difference. Several years ago in Porsche Panorama had an article on the downforce generated by these various aero aids. ANY aero aid is significant compared to the stock fast back.

ked

The clearest expert source on 911 aero issues is (for me) Frere's Porsche 911 Story, Chapter 7 (Body Developments), Aerodynamic Developments (segment). On ride height, Bruce Anderson's Performance Handbook is a great place to start... and finish, for most of us. I recommend them to those who own 911s, &/or are deeply confused.

Amber Gramps

now here is a stylish example of what a duck tail looks like on an early car. had to crop it to get it to load. sorry it's fuzzy.

Amber Gramps

this may be a better angle. it's got a for sale sign in the window if you are interested.

Amber Gramps

bumped for obvious reasons

psychoideas

That's not a tail,................that's Dracula's collar!!

v8_ranch

It's not a tail... it's an airbrake!

JonH

rally cap?

LaughaC

Genuine ducktail cars are so rare that they should all be trailer queens by now since they are practically irreplaceble and their value will drop exponentially in a fender bender.

Aside from the purist benfactor searching for the perfect low-mileage specimen to park in a museum, someone who wishes early cars would not use whale tails may be subconsciouly upset that a '78 looks so similar to their later cars, making them feel a bit less exclusive.

IMHO form always falls second to function on a car that is to be driven to its limits. Originality takes precedence over function on collectibles, which is why restored cars should never be worth as much as survivors in the same condition. It's the scarcity of good survivor cars that drive up the value of restorations.

Today's emerging market of updated American muscle cars that look mostly original will hopefully carry over to our P-cars, but we will need a better public image for that to happen.

Most peole still associate 911 drivers with the snobby doctor in the movie "Caddyshack," the ruthless, spineless manager in the movie "Office Space," and the rich brat who challenged Tom Hanks in "The Bachelor Party." Those charicatures tried to make themselves feel adequate by making others feel inferior, and that's not what our P-cars are about.

Most of us are drivers 1st, and I hope we dispell our reputation as poseurs.

ked

Chris, Interesting perspective...
I'm not sure that a Freudian interpretation of tails is called for. The reason the tail was changed from duck to tea-tray style was in response to gov regulations, not to improve lift-reduction (though the Turbo tail differs, its perimeter reaching further into the airstream, as it is designed for greater speeds, chassis shape, weight and therefore, aero-load). Leffingwell's book "Perfection by Design" has a good treatment of the rear wing development (which I also recommend to all who really want to delve into that history). Upshot is that I am not convinced that a std whaletail delivers more rear lift-reduction than a ducktail on pre-SC 911s, so... is it really a functional issue, or a matter of taste after all? {btw, is your car pictured lacking a frt spoiler to match the rear? - the factory suggests that such a combo is not functional at speed.}

Is the rarity of survivors the base cause for restored cars values to be so high? The market is now rather mosaic, some collector/investors want a survivor even if it is a dog-eared driver, others want nothing except a concours-restored, better-than-new example (for them a fine survivor is just the starting point). And sunken cost has an impact on market value too - a survivor "costs" nothing, a concours restoration makes anything expensive in resale.

Modifying 911s in wild and various ways have been common since the factory started doing so in the late '60s - we have always had updating & now, even backdating. I realize some owners prefer not to mod their own cars (for any # of reasons), but I've never sensed any general heartburn over those who do. But then again, I can't really get into Porsche perceptions of poseur-perceivers either. Now, right after F1 qualifying, lets all go test our winged & spoilered (or non-spoilered) 911 aero package. cheers!

Brian A.

Duck tail on a Targa at the track worked for me.

LaughaC

Thanks, Ked. I wasn't aware the gov't stopped the production of ducktails. My comments were pretty much tongue-in-cheek, in hopes of bringing us back toward a more scientific discussion.

Be they ducktails, whaletails, bobtails, duckbills, or anything else; I'm willing to try everything I can get my hands on. Right now I'm buiding a front splitter while I continue to shop for a used chin spoiler for comparison. I'm too cheap to get a new chin spoiler when it's possible the splitter will work as well and provide more ground clearance for my lowered car. Right now I scrape many speed bumps and average driveways.

Does anybody have wind tunnel results we can consider for various setups?

I don't need to go faster than 130 or so in this car. We're all hoping for the least drag cooefficeint with enough downforce, and there should be some numbers out there somewhere. It would be very interesting to see the corner weight numbers with 95 MPH of wind for each setup, both straight on, and coming from 15' angles in case we start a big slide at speed.

ked

Chris, there are figures presented in Frere's book, photos and this statement, referencing a G-series 2.7: "Rear lift is reduced from 276 lbs to 68 lbs by the duck's tail and to 29 lbs w/ the tray." They seem to make measurements at top speed (makes sense - the effects are most evident). So, the tea tray spoiler DOES have a greater benefit than the older ducktail (note to self: so there!). He also points out some other benefits of the tea tray design: improved engine airflow & cleaner tail lights (those detail-oriented Porsche engineers!). & he states that a tea-tray tail must be balanced by a frt spoiler. Aero remains (along w/ acoustics, & other fluid dynamics, I suppose) one of the most complex real-world science & eng topics (maybe why no one relies exclusively on CFD sw, and utilize expensive wind tunnels, etc). Frere offers 5 pages of written material w/ data - I always find some great info in his book, the definitive insider's, factory-authorized work on the 911. on your project - I wonder if the guys selling wings & spoilers have collected the relevant comparative data? If you source a deformable material for your splitter, and can design one that performs the same (measured) function as the factory front spoiler, you may have yourself an actual product. good luck!

LaughaC

Thanks again. I ordered Frere's "Porsche 911 Story" online tonight.