Elisa Coon
June 1, 2013

Watching the great strides performance shops have made with the 5.0L Coyote platform over the past year, my husband and I just had to add one to our stable. We'd recently sold our boosted Three-Valve GT, and needless to say, we were pretty stoked when our shiny new '13 5.0 Mustang arrived—we just couldn't wait to get the wrenches turning. The seat-of-the-pants feel was impressive and it roasted the tires like it was ready to blaze some 12-second passes—we officially had 5.0L fever.

With a whirlwind of induction options and modifications that have recently hit the market for these new-school beasts, picking the right bolt-on boost wasn't easy. Our main goal was to keep it looking as factory as possible. We also had power goals in mind, and didn't want to limit ourselves with a supercharger that would be maxed out before putting the car in the 9-second zone in the near future. We opted for the Phase Two Roush supercharger kit (PN 421390), retailing for $6,599.99 and rated at 625-flywheel horsepower—more than enough to get your adrenaline flowing.

In this article, we cover Phase One of the installation—the 525hp kit (PN 421388), retailing for $6,099.99. Roush is currently the only manufacturer to offer a three-year/36,000-mile warranty with an optional powertrain warranty in a 50-state-emissions-legal supercharger kit. For the cost, those benefits make this kit a no-brainer.

We proved that just about anyone with basic mechanical skills can take a new 5.0 and mod it with a Roush blower.

Baseline Testing the Stock 5.0

Our first order of business was to head to the only local track (to your author) that was open in the dead of winter, State Capitol Raceway in Baton Rouge, Louisana. We loaded up and headed South for a test and tune session with our barely-broken-in stock 5.0. The weather was sunny and cool with temperatures in the low 60s and a DA (density altitude or corrected altitude) of around 800 feet, according to our Crew Chief Pro and Altronics PerformAire PC trailer-mounted weather station.

We made several test passes with various launching techniques and had a best of 12.83 at 110.8 on the factory 18-inch wheels and tires, with a 2.02 60-foot time. Launching around 1,500 rpm, we saw very little wheel spin, even on street radials. We bolted on a set of Bogart D10 race wheels wrapped in Mickey Thompson 325/50R15 drag radials on the back and M&H 185/55R17 up front. This netted us a staggering 68 pounds in overall weight loss, so we knew there would be a noticeable gain. After several passes, the car consistently showed us 12.7s with a best of 12.73 at 110 with a 2.00 60-foot. Just from drag wheels and tires alone, we dropped a tenth.

To solidify the track results, we decided to dyno-test the car for baseline horsepower numbers at Stang-Hi Performance, also in Baton Rouge. Using its Dynojet, the stock-trim Coyote made 368 rwhp and 348 lb-ft of torque. We were impressed with the results from a completely factory Mustang, but we were starving for more power and quicker track times.

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After the Roush Phase Two supercharger kit arrived, it was time to give rise to the Steed. We chose not to pay a performance shop to install it. Instead, we saved about $1,500 in installation costs and gained the experience of doing it ourselves. We wanted to create a truly DIY scenario that just about any Mustang enthusiast could relate to and even duplicate. My husband, JD, along with fellow 5.0 racing buddy, Adam Yeager, began the one-day, relatively painless supercharger install in our home garage.

Phase One

In this installment, we provide you with the first-hand basic installation sequence, along with any notes that may make the job easier. Literally anyone can install this kit if you have basic mechanical know-how.

Following Roush's meticulously detailed instructions, we disconnected the battery cables and removed the PCM to overnight it to Roush with the supplied FedEx overnight box. Roush recalibrated the PCM with its 50-state-legal calibration, and the PCM was back in our hands in less than 36 hours—impressive service. Don't forget to fill out and mail in the card to maintain the Roush warranty on your vehicle along with your PCM.

One thing we noticed immediately upon thumbing through the approximately 80-page instruction manual was a glaring statement at the top of every page: Premium Fuel Only. You can bet Roush's number-one priority is keeping all conditions as safe as possible in order to warranty these kits.

We also should mention the sticker that clearly states on the PCM to not recalibrate, in bold letters, after Roush has calibrated it and sent it back. If you flash the PCM with another tune, Roush will no longer honor its warranty, and we can't blame them for that. As you can expect, there is a difference between a CARB/emission-legal tune and a custom tune that is designed only to meet the standards of making more power.

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Getting the install momentum going, we placed the car on jack stands and removed the front wheels, radiator trim cover, and bumper cover. From there, we moved to the engine bay, removing the plastic engine appearance cover and air tube. Disconnecting the throttle body electrical connector, then the EVAP emission canister purge-valve tube and electrical connector, we removed the PCV purge line and the fuel supply hose from the fuel rail, and the brake booster hose from the intake manifold.

Since our Mustang is an automatic, we disconnected the brake booster vacuum hose and aspirator assembly and set them aside for later use. After removing several miscellaneous lines, we unbolted and removed the stock intake manifold. The directions are straightforward and simple for any weekend warrior.

Next, we removed the factory accessory feed belt and water pump pulley, upper radiator hose, and electric fan and shroud assembly. For removing the A/C compressor belt, it was as simple as cutting the belt itself as it wouldn't be used again. We disconnected two transmission cooler lines and lowered the transmission cooler. Using the brake booster hoses we saved earlier, we trimmed them per Roush's specifications.

Moving on to modifying the front engine cover, we were elated to see that our '13 GT had less webbing on the cover itself than the '11-'12 models. We were required to remove three sections, whereas the previous years of the 5.0 required removing a total of seven pieces. That's a whole lot of cutting.

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Before making our cuts, we covered the entire engine bay with a set of spare bed sheets to keep any metal shavings from getting anywhere they don't belong (see photo). Marking our engine cover where needed with a Sharpie marker, we used an air die-grinder with a cutoff wheel to make our cuts. This simple tool can be found, in electric or air form, at any hardware or Harbor Freight store, and is a necessity for this project.

It was time to start working on the wiring connectors. Roush supplied harness extensions that we used to extend three sensor wires. This is the most tedious (might we even say annoying) and time-consuming part of the install. It's extremely important to pay close attention in order to do this correctly.

The following sensor wires that need to be extended are the throttle position sensor (TPS), canister purge valve, and MAF. We removed one of three connectors from the PCM and removed pin C-56 and spliced one of two ACT loom wires onto it, then replaced the pin in the exact same location. The other wire with the OEM-style pin on the ACT loom was placed in the C-36 location on the same connector. It's always best to double-check this step to prevent related electrical gremlins.

We assembled our Roush heat exchanger and brackets, along with the PCV purge hose onto our supplied lower intake manifold, and then removed the stock EVAP purge valve and installed our new throttle body spacer. From there we installed our Roush de-gas bottle (intercooler reservoir). We extended the trans cooler lines with the supplied hoses and hardware, and zip-tied them out of the way to keep the engine bay clean and clutter free.

18. Roush lower intake manifold after being torqued properly and awaiting the installation of the TVS supercharger unit.

The next steps seemed to go quickly as we did all the necessary procedures beforehand. First, we mounted the heat exchanger and the intercooler pump, and ran all the hoses to complete the intercooling process. It took both JD and Adam working together to place the lower intake manifold onto the engine. The fuel rails and injectors were then torqued down to Roush's specs. Again, using both of their hands, they placed 2.3 liters of TVS boosted badness onto the manifold and torqued it down—Roush supplies all the necessary torque specs. We then installed the throttle spacer and twin 60mm throttle body along with all hoses and connectors.

Next was the Roush FEAD (front engine accessory drive) system. Using hardware that came on the original engine cover, we installed the upper FEAD bracket and idler pulleys. We placed our supplied belt on the available pulleys and installed the lower bracket with a tensioner. Using a 17mm socket and ratchet, we pulled on the tensioner, which gave us enough slack to completely install the drive belt onto the supercharger. After installing the water-pump pulley, we reinstalled the other belt. A clear diagram illustration of the belt routings is in the instructions.

With the install coming to a close, we still had some odds and ends to finish up. We installed the fan shroud, upper radiator hose, and de-gas bottle inlet hose and clamped them in their respective locations. Reinstalling the upper airbox lid and clean air tube, along with the aforementioned modified brake vacuum hose, we were approximately 10 hours into this installation and the finish line was near.

Wrapping things up, we installed our bumper cover, radiator trim cover, wheels, and filled our radiator and intercooler system with factory-spec fluid. We re-checked our transmission fluid levels and noticed about a half-quart of fluid loss from previously disconnecting the ooler lines.

With little effort, we now have a Stang that is one full-second and a tenth faster than our stock runs, and it's still 50-state-legal and under warranty!

We could barely wait to fire her up, and with a long day of work behind us, we owed it to ourselves to see if our slick backyard mechanic skills were up to par. She started right up and sounded oh-so-sweet. This proves that any average Joe can handle a Roush supercharger install with most basic handtools in their garage. Roush has provided an intuitive set of directions that won't leave you scratching your head or throwing wrenches—and for that, we thank them.

Putting Our Phase One Roush Supercharger to the Test

With our newfound boost, we headed back to Stang-Hi Performance in Baton Rouge for another dyno session. Cody Cutforth of Stang–Hi strapped our Coyote to the rollers and made three close-to-identical pulls.

The air/fuel was spot-on, as one would expect from the OEM quality engineers at Roush. Our Pony put out a solid 470 rwhp and 417 lb-ft of torque—an impressive 100 hp more at the tires than it made in completely stock form. These numbers are dead-on with what Roush estimates for the Phase One portion of the Phase Two kit. And, of course, we plan to crank it up next issue.

The pulley size provided for both Phase One and Phase Two is 85 mm, and the only difference between the two is a less-restrictive Roush cold-air intake. At that point, it's up to the owner to provide their own ECU tune—in most cases, much more aggressive since it wont be smog-legal like the Phase One tune.

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With the numbers on paper, it was time to see what our wild Coyote could do on the track. Again, we rolled out to State Capitol Raceway in identical weather as day one; it was sunny and cool with a DA of about 800 feet above sea level. With the lighter wheels and sticky tires, she bolted to a very quick 11.61 at 118.4 with a 1.69 60-foot, and with us launching slightly higher than before at 1,800 rpm.

With little effort, we now have a Stang that is 1.1 faster than our stock runs, and it's still 50-state-legal and under warranty! Not to mention it's launching like a bat out of hell and even brought the front tire off the ground a couple of inches. We backed it up with several 11.64 passes with very little cool-down time between runs, which tells us heat-soak might not be a big issue.

The throttle feel was a little different this time out due to the new calibration from Roush. We realize it's there for a good reason, but the torque management aspect that still remained after the Roush calibration leaves racers like us itching for a custom tune. It's a little sluggish out of the hole, and you don't feel the car wake up until about the eighth-mile mark, but then it really starts propelling you through the traps. The potential gives us a lot to anticipate.

Overall, it's a very impressive and easy-to-install upgrade with the quality and reliability we have come to expect from our friends at Roush. It's truly the epitome of OEM quality fitment.

We will be covering Phase Two as well as a comparison of a custom tune verses Roush's super-safe calibration, so you'll want to keep an eye out for the next segment and look for the Roush-boosted Pony at an NMRA event this year!

23. Even with the stealthy stock wheels and tires, the GT can run mid-11s at 118 mph.