In one of the first, if not the first documented outings of a 2015 Mustang GT at a top speed event, HiPo Joe Charles recently hit the ½ mile straight away for a day of testing and tuning. Originally planning to take his Coyote Stock racer, Charles discovered an issue shortly before. Instead he decided to load up his wife’s brand new 2015 Mustang GT Performance Pack for a few passes down the tarmac.

Keys in hand after a stop at MGW for a shifter install, Charles, along with Jason Sloan and Jonathon Parker, with the Deep Impact ’15 GT in tow, recently headed to Ocala, Florida for the WannaGoFast Runway 1/2-mile event at Jumbolair strip. Taken to the event absolutely stock with the exception of the shifter, Charles was interested in running the car to establish a baseline and document the differences in performance while testing aftermarket performance modifications. Those included a DiabloSport tune designed to work specifically with 93 fuel testing and a JLT Cold Air intake kit as well as the testing of the Ford Performance Sport Cat-Back exhaust system.


A great venue for testing raw street car performance at top speeds, the WannaGoFast event provides racing events to both the public and private, with the most recent one taking place at the Jumbolair strip. This provided the perfect setting for Charles to experience both the stock performance of the 2015 Mustang GT Performance Pack and performance of the aftermarket enhancements. Charles was better able to determine on the 1/2-mile strip, differences in overall performance at top speeds for longer durations on each pass than on a typical drag strip. Essentially testing street performance combinations and capabilities in a controlled environment, Charles gathered real world performance data of the new S550 platform first hand.


With a plan put in place to modify the car throughout the day of testing at the event, Charles, came equipped to do just that, modifying the car between passes. Enlisting DiabloSport as the tuner of choice, a new InTunet handheld tuning device was set up with a new tune soon to be released to the public.  The tune is designed to work with both the JLT air kit and 93 Octane for the 2015 S550 GT platform. Also on board during testing, assisting in increasing power to the pavement, Charles selected the Ford Performance Sport Cat-Back exhaust system, part number M-5200-M8SB to help in the reduction of weight and to aid in the increase of more horsepower.


Dyno tune testing results show peak torque of 383.5 lb-ft and peak horsepower of 398.1

DiabloSport Tune

We set up our small handheld tuner, the inTune with a JLT CAI 93 Octane tune. The tune is designed to work specifically with 93 octane and the JLT Cold Air intake on the 2015 Ford Mustang GT 5.0.

Uploaded with the DiabloSport InTune tuning device via dyno tune testing, horsepower increase is reported to be in the neighborhood of 28 hp with torque increasing 50 lb-ft, at the rear tires, over the factory numbers. Soon to be available this specially designed street tune will be offered with the purchase of either the inTune or Trinity tuning device. In addition, included with the tuner will be tunes specifically for use of higher octane 93/91 fuel running without a cold air intake. DiabloSport estimates owners will pick up around 15 horsepower and 30 lb-ft of torque over stock with this specific tune.

JLT Cold Air Intake

A proven way to see an instant power increase, Mustang enthusiasts have long relied on a cold air intake. Charles choose one from JLT Performance CAI. The JLT intake is designed to bolt right on to the S550 with no permanent modifications, and features an air filter heat shield and a larger intake tube opening. Charles says gains were immediately noticeable with the intake combined with the DiabloSport tune .

Ford Performance Sport Cat-Back Exhaust System

The Ford Performance Sport Cat-Back exhaust helps move more air through the exhaust, and it’s also around 30 pounds lighter than the factory installed system. The exhaust was also installed on the spot at the track with the help of a couple buddies Charles brought along. Charles says he noticed increased horsepower and performance following this modification as well.

The Track- Comparison Stock Passes v Modified Passes

The day began with a weather delay due to rain. With a late start, Charles was only able to make four passes completing two as stock and two with the modifications. Enough for a driver of Charles’ experience to make a good assessment and documentation of the differences in performance. This go fast only event offers no time slips so available performance was solely gauged in MPH.

Newton's Laws

Newton’s first law states that objects in motion stay in motion unless outside forces act upon it with the second law stating that anything with mass, such as a car, with a net force acting on it will accelerate. The wind resistance also known as drag becomes the force working against the object (car) will at some point become an equal force to the car and in order to overcome the force and continue to accelerate at higher speeds more net force (horsepower) is needed to continue acceleration of the object. Every force has an equal and opposite force. Overcoming the opposing force in the case of a car fighting wind resistance as the vehicle accelerates and works to achieve a higher MPH it will require more horsepower to do so the faster it travels.

The best stock pass was 132.74 mph. Keep in mind at these speeds the car is fighting mother-nature, as the faster you go you will encounter something known as wind resistance. This is about the best you can expect from a stock 2015 Mustang GT equipped with the performance pack. The science behind wind-resistance or what many refer to as drag simply means the faster an object moves the more force or resistance it will encounter. So in order to overcome wind-resistance as an object moves faster it will require more power to move at a quicker pace. Essentially, at 132.74 miles per hour on a 1/2-mile track, in order for a stock 2015 GT equipped with a performance pack to obtain a faster rate of speed it needs more horsepower.


Stock pass achieving 132.74 mph.

With that said Charles and his team, upon the finish of the second stock pass, installed the JLT air intake along with the Ford Performance Exhaust system. The small DiabloSport handheld InTune was used to upload the newly designed street tune for the 2015 Mustang GT and take full advantage of the modifications. Charles says an immediate difference was felt at ignition with an even more noticeable difference felt on both the third and fourth passes.

Charles says wheel spin was felt 75 feet out even with launching off idle with a deliberate slow attempt to slip the clutch and keep spinning at a minimum with the newly added horsepower. With the significant gains in torque,Charles felt the unleashing of the power all the way through the ½-mile pass. With a best mph of 134.699 after modifications, just on the verge of 135 mph, taking into consideration the adaptive learning strategy that occurs with any changes to the computer it is very likely had Charles made a 5th and 6th pass he would have without a doubt hit the 135 mark.

“This type of racing is very different from NMRA competitive racing.” Charles says. “This form of racing is great for the everyday street car, testing the full capabilities in a safe and structured situation.” he continued.

This is one of the first if not the first documented cases of the 2015 Mustang GT enhanced with some pretty simple bolt ons and a tune competing in a high speed competition, showing significant improvement in performance for a relative low investment. Great news both for the everyday enthusiast and for the more serious competitor who is interested in powering up their new steed.

HiPo Joe Charles is looking to hit at least the 135 mph mark, so he will be returning to WannaGoFast in Georgia for the ½-mile shootout event at Heaven’s Landing Airport in Clayton, Georgia on May 30th and 31st of this year. Look for StangTV to follow the continued progress and performance of this Mustang GT, and more in the coming years to see what others can do with the S550 at standing 1/2-mile and mile events.