Steeda Q500 Mustang GT - Storm Surge

In fact, the Steeda catalog is an a la carte shopping mall, where you can buy just about anything for your car. If there are too many choices for you to make, Steeda has prepared a number of packages from which to choose. The Q350 is the entry level Mustang packing 350 naturally-aspirated horsepower, and once you have mastered that, you jump right into the Q500. Believe it or not, the Q500 isn't the most potent package that Steeda offers. There is a Q650 that should give you your speed fix if 500 hp isn't enough. If you've got a Ford Focus, Fusion, V-6 Mustang, or a Shelby GT500, Steeda has you covered as well.

Adapting And Overcoming
About 20 years ago, many thought the computer-controlled cars of the day were doomed when it came to having fun and making horsepower. Twenty years later, Steeda shows you how to have supercar horsepower, big-block torque, and slot-car handling--all thanks to the latest in computer-control technology. Engine control units, or car computers, have made leaps and bounds since the '80s, and the Steeda Q500 we recently sampled features the very latest in computer control. When flashed into the Mustang's "Spanish Oak" processor, Steeda's Adaptive Performance Calibration (APC) actively monitors the engine's performance and makes adjustments as needed.

"When you put a cold-air kit on an '05-and-up car, it cannot maintain the proper air fuel ratio and it ends up running incorrectly," says Steeda sales manager Gus Irizarry. "There are a few exceptions to this, but those kits that do run correctly without tuning are doing so by not substantially increasing engine airflow. Without a substantial increase in airflow there will not be a substantial increase in horsepower. In our own testing with kits like these, as well as independent testing, we have only seen gains of 7 to 8 hp without tuning, and around 15 to 18 hp with tuning."

Your standard computer programming doesn't adapt for modifications, nor does it adjust timing based on fuel octane. Irizarry adds, "With the naturally aspirated setup, the owner can run any level of fuel octane from 87 to 93 octane and the computer will automatically adjust spark timing to provide maximum, detonation-free spark timing and power. Of course the maximum power is achieved with the higher octane gasoline, but the owner does not have to worry about retuning with a handheld tuner every time he wants to change gas grades or worry about being stuck with one type of fuel due to only having a high octane tune. The vehicle will automatically adjust and provide the best performance for the conditions."

You'll need slightly more than a stock Mustang, though, to enjoy the benefits of the Adaptive Performance Calibration, as it needs to be used with Steeda's Cold-Air kit and Charge Motion Delete Plates in order to be CARB-legal. In addition to its adaptation to various gasoline grades, the APC has also been tested on a naturally aspirated engine with Comp Cams NSR (no spring required) camshafts and found it can adapt to them as well.

"On supercharged applications the system is designed not only to adjust timing based on fuel in the 91 to 93 octane range to keep the motor from dangerous detonation, but it can also adjust to changes in boost," says Irizary. "So if you are running a Whipple with 8 psi of boost and change several pulley sizes to take it up to 12 psi, the system will automatically adjust fuel to maintain proper fuel levels and timing for best power without detonation."

In order to stay CARB-legal, the Adaptive Performance Calibration is currently limited to about 500 rwhp, as the programming received its CARB certification using a certain injector size. You can, however, pop in some bigger injectors, add a bigger mass air meter, and take power output well north of that.