We put this stock Pony through...
We put this stock Pony through its paces on the dyno. All testing was done in Fifth gear to ensure accurate readings, as the '11 Mustang's six-speed manual transmission features a 1:1 ratio in Fifth gear. Previously, all stick-shift Mustangs were tested in Fourth gear, as that yielded a 1:1 ratio. In stock form, Frank Lanzas' tester put down 374 hp and 360 lb-ft of torque to the rear tires. To put this in perspective, the famed '03-'04 Terminator Cobras put down around 370 rwhp in stock form-these new 5.0s are bad!
The highly anticipated '11 5.0-powered Mustang is a legend in the making. Yes, we believe the new 5.0 definitely is the Pony-and the engine-that all others will be measured against for a long time to come. As you well know by now, Ford equips '11 GTs with a 5.0-liter, Four-Valve mill rated at 412 hp at a stratospheric 7,000-rpm limiter. With such a well-engineered power-plant, it makes you wonder how much more room there is for improvement, especially considering it comes factory-equipped with cold-air induction as stock equipment.
From experience, we've learned that one of the simplest and most cost-effective methods of substantial power gains is to uncork the induction side of the motor. Upgrading to an aftermarket cold-air induction kit is probably the most common mod made by late-model Mustang enthusiasts. It's no mystery why as the performance gains, ease of installation, and relatively low cost associated with this upgrade score big with consumers.
In the case of late-model Mustangs, many CAI systems require reprogramming the computer in order to maximize performance, but more importantly, to avoid the dreaded Check Engine light, as well as driveability issues. Skip this important part of the equation and your engine could pay dearly with its life due to an overly lean air/fuel mixture.
For the new 5.0, Steeda Autosports teamed up with SCT to provide a one-two punch in the form of a cold-air induction kit and a handheld computer tuner/flash device to take the hot new 'Stangs to the next level.

Steeda and SCT collaborated...

Steeda and SCT collaborated to put together a well-designed system. Notice how the Steeda cold-air kit includes an airscoop that retains the stock cold-air duct behind the front bumper. The use of this feature ensures the absolute lowest air-intake temperature possible for maximum power. In addition, the Steeda air-inlet tube accepts the stock Induction Sound Tube. Although that doesn't add any power, it sure provides driving enjoyment.

With little more than a screwdriver,...

With little more than a screwdriver, the factory air inlet can be removed in a few minutes. Notice the stock plastic engine cover has been removed temporarily to gain access to the throttle-body clamp.

Here is a close look at the...

Here is a close look at the intricately engineered cold-air kit by Steeda. We really dig the fact that it still makes use of the factory cold-air scoop behind the front grille, feeding in an ample supply of ambient air. The stock mass-air sensor is transferred to Steeda's billet-aluminum mass-air housing, which features a built-in velocity stack to promote maximum airflow. Steeda goes the extra mile and includes rubber trim to dress the edges of the stainless steel heat-shield and sturdy brackets to keep things buttoned down.
Steeda's Ultimate Induction Pak (PN 555-3935 for manual and PN 555-3936 for automatic; $739) features the company's cold-air induction kit and SCT's X3 flash tuner. Although Steeda offers both items individually, there is a price savings when purchased as a kit. Furthermore, Steeda's cold-air sends a lot more air across the mass-air sensor, so a flash is mandatory.
To be expected with the Steeda/SCT combo, the use of 91-octane fuel (or higher) is required. We don't suspect many 'Stang freaks will have a quarrel with burning premium fuel in exchange for a healthy bump in power output. The extra couple of bucks spent at the pump during fill-ups is a small price to pay for the satisfaction of smoking the competition.
Installing the CAI and PCM update is so simple that even semi-mechanically-inclined enthusiasts should be able to handle the job in less than an hour. For simplicity, the flash tuner comes pre-loaded with Steeda's standard cold-air tune, which eliminates any guesswork and truly makes this a plug-n-play procedure. The more aggressive, custom tune that we're using is an additional-cost upgrade that requires providing your Mustang's PCM code.
Once complete, it's always a good idea to visit your local dyno shop and verify the end results-specifically, to ensure that the air/fuel ratio is within the allowable range when the hammer is dropped.
On The Dyno
We blasted the Mustang on the dyno to the tune of 387.64 horses and 367.93 lb-ft of torque on the ground. As impressive as the peak gains are, study the accompanying dyno data and you will see that power and torque both surpass the stock levels as early as around 2,500 rpm. From that point on, the Steeda/SCT combo simply runs away from the stock setup. Keep your foot down, let the 5.0 Coyote wind itself out, and you will be rewarded with larger gains that increase with revs. The SCT-set, 7,000-rpm rev-limiter really takes advantage of the new 'Stang's top-end potential. Noticeable performance gains with little effort-what's not to like?

Installation is basic-no cutting...

Installation is basic-no cutting or drilling necessary. Steeda's CAI makes use of the factory mass airflow sensor and original induction mounting locations. Once the heat-shield and air filter are secured, the stock PCV tube and IST are reattached. Note the high-flow, reusable air filter features an inverted cone for maximum surface area, while the rubber trim forms a seal against the hood when closed to prevent hot air from being drawn into the engine.

Late-model Mustangs have become...

Late-model Mustangs have become synonymous with aftermarket flash tuners. For this exercise, SCT's X3 unit (PN 3000) is used to transfer a custom program developed specifically for Steeda's CAI. Keep in mind that the use of premium 91-octane (minimum) fuel is required to support the higher ignition timing levels that have been calibrated in the tune.

The end result has a handsome...

The end result has a handsome look that blends in with the factory theme of sophisticated muscle. Notice how the stock engine cover fits nicely in place. At this point, Frank Lanzas' 5.0 'Stang has an excellent foundation upon which to continue adding power.
| Baseline | Steeda CAI | Difference |
| RPM | HP | TQ | HP | TQ | HP | TQ |
| 2,500 | 135.78 | 297.10 | 142.88 | 300.17 | 7.10 | 3.07 |
| 3,000 | 166.11 | 300.82 | 176.06 | 308.21 | 9.95 | 7.39 |
| 3,500 | 209.07 | 322.96 | 225.27 | 338.04 | 16.20 | 15.08 |
| 4,000 | 251.66 | 338.91 | 268.57 | 352.64 | 16.91 | 13.73 |
| 4,500 | 301.38 | 359.75 | 310.71 | 362.65 | 9.33 | 2.90 |
| 5,000 | 322.17 | 345.32 | 337.53 | 354.55 | 15.36 | 9.23 |
| 5,500 | 355.14 | 345.42 | 365.09 | 348.64 | 9.95 | 3.22 |
| 6,000 | 360.38 | 320.81 | 372.66 | 326.21 | 12.28 | 5.40 |
| 6,500 | 372.61 | 305.78 | 387.61 | 313.20 | 15.00 | 7.42 |
| 6,900 | 370.11 | 285.87 | 378.03 | 287.76 | 7.92 | 1.89 |