Does running a whale tail hurt fuel economy?

[stewartjp]

Hello Everyone,

I was wondering if running a whale tail impacts fuel use and if so how much?

Logic says that it creates extra drag so it should use more fuel. But is it a reality?

Thanks

Stewart

[911SauCy]

I'll take your visitor tag, please grab a refreshment on your way out....

[Cevan]

I think mine does. That's why I never go over 3000 rpms.

[82 SC]

LOL. You might be the first one to ask If you have 2 deck-lids try and swap them out and let us know. For most of us unless it is running poorly we don't worry about gas mileage, its about the drive For fuel mileage i use my TDI jetta. If I want to burn some fuel I tow with my Suburban. We also have an all electric Nissan Leaf. Vehicles for all occasions.

[Jeff NJ]

When I bought my car and took my dad for a ride, his first question was "what kind of gas mileage do you get?" My answer was - "who cares?"

[Bergo]

haha, I've never even stopped to consider fuel mileage in my vintage sports car, when it goes below 1/4 tank, I fill it up and toss the receipt.

[ganun]

Hi Stewart, My 2cents......just for fun
from what I remember seeing in a chart showing the effect of a round tail, a shape similar without a whale tail and a cut off tail, arguably maybe similar to a whale tail, the drag goes up with speed exponentially with the rounded back whereas it goes up more linearly with a cut off (Kamm) shape. So it would seem that at speed there is a fuel saving with the whale tail, no idea how much.
Also the whale has no down force angle only the up-turned lip. If it did have an angle to promote substantial downforce it would increase drag.
BTW the tail does not add downforce, it reduces the amount of lift at the rear, similar to the exponential to linear relationship of wing and no wing.

[914efi]

I recall reading that the whale was more aero efficient than the duck, hence the change. Maybe it was more downforce with the same drag?

[ganun]

To try and limit the lift at the rear, no downforce added.

[nene]

You are adding weight..........................so a heavier load to carry, so yes, mileage will take a hit.

[wwest]

Originally Posted by ganun

To try and limit the lift at the rear, no downforce added.

Limiting lift beyond non-spoiler equipped will always add downforce.

[turbobrat930]

Darn, and I thought my bad gas milage was from the 100Lb injectors that I am using... I guess its this damn GT-2 EVO wing....

[IMG]20150510_182600 by Brad, on Flickr[/IMG]

[TheSt|G]

I find the best way to save gas is to leave it parked in the garage.

[nene]

BTW JoeBob, I am catching up on your posts!

[tributeventures]

It's a proven fact that the Whale Tail in a great improvement in fuel economy over the Duck Tail. That's why during the initial IROC years, Penske switched to the Whale tail over the Duck Tail because he was paying for the gas for all 14 IROC cars during the series.

[jwakil]

The whale tail helps with cooling for sure, forcing more air to the engine. Fuel economy is probably a wash between extra weight & drag coeff vs getting more air for turbo intercoolers and intake and less rear lift.

[Cooper911SC]

Covered many times here...

From Frere's Porsche 911 Story,

On a G series 911 ('74-'89)
Cd is REDUCED 2% by adding a whale tail and chin spoiler.

Rear lift is REDUCED from 276lb lift to 29lb at top speed.

On my SC it was seat of the pants noticeable over 100mph. Definitely settled the car.

Cooper

[stewartjp]

Thanks guys 2% extra isn't a whole lot.

[JOHN21BLACK]

If your worried about fuel mileage, then maybe you should get a prius. I wouldnt care if my car got 5 mpg.

[Bob Kontak]

Originally Posted by stewartjp

Thanks guys 2% extra isn't a whole lot.

The man just said it reduces coefficient of drag 2% based on an extremely solid source that can be verified.

You asked if the tail creates drag. Cooper says no - In fact it reduces it by a measured amount.

Then you say that isn't a lot. What am I missing?