R U Subaru? – Tuning Forced Induction Cars and Alcohol Injection

The voice of the people is divided on the huge 04-07 STI wing. Some hate it, some love it, some think it looks ugly. Some say it’s only for looks, and then some say that it’s very functional. Let’s see whether you need that wing in the back.

We see a lot of STI owners remove their stock factory wing and replace it with fancy aftermarket creations. And some remove it completely or replace it with the low WRX spoiler. Is there a sane reason to remove / replace the stock STI wing?

Hate the wing: Common Reasons They’ll Give You

• STI rear spoiler is bulky and ugly;
• it weighs too much;
• it is not functional and for looks only;
• it attracts attention;
• wings are for ricers.

Love the wing: Common Reasons They’ll Give You

• it is functional;
• it makes the STI look like an STI;
• it attracts attention.

Let’s speak to the functionality of the STI wing. We hate to disappoint some people, but it actually does work. Subaru spent hundreds of thousands of dollars to develop that particular wing and then spent many, many hours testing and tweaking the wing in wind tunnels.

The wing is specifically designed to provide a significant amount of downforce past 70 mph road speed. The wing reduces lift and increases the high speed stability. The STI aerodynamics were further enhanced in 2006, with the addition of a roof vane spoiler, which stabilizes the air flow to the rear wing.

The WRX spoiler does not come close to the STI wing in realized downforce. So replacing the STI wing with a WRX wing may not be such a good idea if you plan on racing or just going fast once in a while.

Removing the STI wing will significantly decrease the downforce at high speeds and yes, you can notice a difference at 120 mph, even more so at 150 mph. Do you modify your car for performance or for looks? Would you rather have stability at speed?

Replacing the STI wing with an aftermarket spoiler is an equally bad idea. Just think about it for a moment using common sense – do you really believe that some aftermarket, low-production-run manufacturer will invest hundreds of thousands of dollars to design their wing? Will they then take their ‘cool-looking’ carbon fiber wing, put it on the STI and spend weeks in the wind tunnel tweaking it?

No manufacturer will go through that expense and you are getting a non-functional, poor excuse for a wing that only looks ‘fast’. Prodrive did do some serious R&D for their WRC wings, further improving the STI wing. The real WRC wings are even more functional than a stock STI wing, and cost a whole lot more than a ‘cool’ aftermarket wing. We wonder why that is?

We see a lot of ‘cool’ aftermarket wings put on STIs and other cars. The coolest thing about them is that at speed, the droplets of water stay on most of those wings, meaning there is no air flow anywhere near the aftermarket wing. In fact, most aftermarket wings will hurt your car’s performance and high speed stability – they don’t work as they should.

Even if you don’t like the looks of the factory wing on your 2004-2007 Subaru STI, it is probably a good idea to keep it there, it is an excellent performance part that does a wonderful job at keeping your car stable at high speeds.

Below is a gallery of actual wind tunnel testing of the STI wing and roof vane spoiler. Testing was done at around 70 mph. As you can see the airflow is perfect and the stock wing is very functional. Don’t remove or replace it, use common sense

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This entry was posted on Friday, July 30th, 2010 at 9:56 am and is filed under Tuning Must-Know, Tuning: How & What. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.