I'm looking at alternate rear spoiler options for my car to increase rear grip at speed (high speed cornering). Ideally I'd like an alternate spoiler that I can change out as needed, for which I would likely make over the winter. However, alternately I'd consider a OTS spoiler if there is some test or analysis data out there showing effectiveness at speed.

Is anyone aware of data that shows the net downforce of some of the spoiler options out there? I used to be handy enough in Fluent to model something up quickly but I haven't worked in that program in years... any engineering folks out there who have or could model up a couple options? Or if data exists for some of the spoilers out there, I'd be interested to see.

May have an option to pick up a CS spoiler, any data to support that design's efficiency compared with the base GT?

 

Just going by 2 things after installing the CS spoiler
1)Back of trunk and rear bumper are dirtier
2)Spray driving in the rain is about 2 foot higher behind the car
1 is telling me it is creating a lower pressure behind the car and 2 is pushing the air up higher than the stock spoiler. Even driving in the rain the whole trailing edge would be wet while the stock lip would be the 3 outside inches.
The rear felt more planted at speeds over 75-80.
Even the Camera Spoiler gets more air than the stock lip and the GT500 is more yet.
If the Pedestal CS spoiler was at least 1 inch further up it would help it even more, but being adjustable would help immensely.

 

The GT500 spoiler has been tested and does provide more downforce at speed, the 13-14 GT500 has been tested over 200 mph.

 

I think the gt500 lip with the gurney flap would be your best bet. Or maybe the rtr lip

 

I'm new here so be gentle with me if I sound ignorant.
I also am looking for functional spoilers, both chin and rear, but I'm going to have to settle for off the shelf products. As I understand it here, the GT500 rear spoiler should be the best for an OTS rear spoiler, am I correct?
Another member here said he noticed a .5 to 1.5 mpg increase (depending on type of driving) in gas mileage after installing a Roush chin splitter. That would seem like a significant reduction in drag and performance increase. Is there a better chin splitter for the 2013 GT?

 

My two cents on the topic. Rear deck spoilers and chin splitters add parasitic drag to a car and will not increase fuel economy. It’s not their design intention. Anytime you add a trinket to your car that is designed to alter the airflow and increase down force, you pay for it. “Down force” is nothing more than redirection of motion (Typically forward) to down force. Costs associated with it include lower top speed, increased ET’s and lower fuel economy…force is not free!

Most of the front splitters available for these cars are not much more than window dressing since they do not ride close enough to the ground to fulfill their true design purpose: to route air around and over the car verses allowing it to flow under it. When the air is moved or re-routed over the top of the car it adds drag. Think about it, you’re lifting air that wanted to go under the car and FORCING (Oh oh…there’s that word!) it to move over the top of the car. The increased air pressure over the top of the car adds downforce (A good thing if you are looking for that). It’s the same as an airplane wing working “Upside down”. An airplane flies because of the differential pressure (DP) on measured from its top side to its bottom. Delta P makes lift across the body…higher pressure below verses above. The faster air travels over the surfaces, the greater the lift for a given airfoil (Or down force for car body shape).

The rear deck spoiler is doing essentially the same thing as the splitter however it acts on its own design verses using the cars body as the force generating wing. On any given airfoil design the greater it’s angle of incidence, the greater the down force (Or lift) at any given speed, however, the greater the parasitic drag as well. As I said earlier, it’s a trade-off based on need.

In an all-out application you would first move weight around to greatest advantage before you were cornered into having to add parasitic drag to accomplish greater load on one end of the car. In the real world I suspect most of us are not pushing our street cars to the point where we will ever take much, if any advantage in aero down force. Other shortcomings in the chassis or tires will typically surface well before we could.

I added a rear deck spoiler and splitter to my car because I liked the look and was willing to accept the reduced efficiency they brought to the car.

Regards,
John

 

the pedestal spoiler that came on my v6 seems to have a good amount of down force. i think its the same as the cs/gt spoiler though. i have rub marks on the mmd tail light trim where the trunk lid was pressed down on it. im guessing its from the down force of the spoiler although i have no proof thats what it was from.

 

I think the GT/CS spoiler is the same one they put on the Boss Laguna Seca. I'm thinking it must provide some downforce advantage over the standard Boss/GT lip spoiler.

 

Let me know if I can put you in contact with one of our experiences testers/engineers ... we have this functional wing:

http://www.steeda.com/store/steeda-f...6-STEEDA-WING/

You can reach me at tim@steeda.com if you have any questions.

Best Regards,

TJ

 

http://www.steeda.com/store/steeda-f...6-STEEDA-WING/
Very interesting wing. Looks like it would have minimal drag for the amount of down force. I noticed that if you were replacing the stock factory spoiler that the 2 outer holes in the deck lid would need to be plugged or filled. Where can I get the plugs?