For decades, blowers and Mustangs have been fast friends. Because they combine always-available power from a system that packages well in a Mustang engine compartment, superchargers have long held the mantle as the top of the bolt-on ladder. In short, for street cred, adding a blower is an instant ticket into the club.
We've looked forward to the moment we could add a supercharger to Ford's latest engine masterpiece from the moment we laid eyes on it. However, we were warned from the outset by Ford engineers that the Coyote 5.0 was maximized for naturally aspirated power, but not built to withstand boost.
Of course, we just had to find out for ourselves, and when Roush Performance announced its Roushcharger kit for the '11 GT, we knew it was worth a look.
Although known for its racing and high-performance aftermarket business, Roush is also a supplier that works directly with Ford on many engineering projects. With close ties to Ford, Roush was able to work directly with factory engineering data to create a comprehensive supercharger kit. Key to this system was the creation of a new lower intake manifold encompassing the air-to-water intercooler, similar to the factory induction on the Terminator Cobras and GT500s.
"Although the construction and materials are the same, the intercooler is larger in all dimensions than the one used on the Terminator program," explained Erin Dmytrow, director of engineering at Roush. "It is identical in size and performance to the intercooler used on the GT500, and is also the same unit we used on our previous R2300 offerings (i.e., P51a and b, '10 Stage 3 and 540RH vehicles). The overall intake volume was decreased substantially from previous designs to optimize throttle response while still achieving maximum levels of performance."
"Our biggest challenge came through the front engine accessory drive. In stock form, this is a dual sheave design in the 5.0 engine. The first sheave, which is located closest to the front cover, is dedicated to the A/C compressor. There isn't a tensioner on this sheave as it uses a tensioner-less belt. The second sheave contains a light-duty tensioner, a water pump, and alternator," Erin added.
"After considering all the options, we decided to design an all-new first-sheave FEAD system to drive the Roushcharger. This allowed us to integrate a heavy-duty tensioner that was designed to handle the increased load of the R2300 supercharger, and apply this load closer to the number-one main, thereby reducing the strain on both the bearings and nose of the crankshaft."
Rounding out the system is a re-engineered front-engine accessory drive, specially engineered 47-lb/hr injectors, a heat exchanger, an intercooler pump, a rerouted air induction, and the necessary wiring to run the intercooler pump. In practice, the kit is clean and simply looks factory, but the trick, at least early on, is that the kit was only available as a $5,999 tuner kit with no calibration. A warranteed version with a Roush calibration will likely be available by the time you read this, but for our purposes we needed a tuner to make the magic happen.
It just so happened that Justin Starkey of VMP Tuning was getting his hands on one of the early Roush kits for his wife Rebecca's new '11 GT automatic. He asked if we were interested in covering the install and test, and we jumped at the chance. We've had the opportunity to work with Justin on several projects over the years, most notably his tuning of our own Project Vapor Trail GT500. Quite simply, he knows his way around a Mustang's PCM. We knew he'd be able to get the Roushcharger running with a sharp tune.
Of course, the '11 Mustangs pack a new, more powerful powertrain control module to take on the additional duty of controlling the Twin Independent Variable Cam Timing on the four-cam engine. Essentially, there's a lot more going on in the head of the new Mustang, but tuners, like Justin, have taken to it quite readily.
"The overall function of the new Copperhead PCM is similar to the old PCMs, but with some important changes. The addition of dual factory wideband O2 sensors and full-time, closed-loop operation has made the PCM more capable of dealing with changes," Justin explained. "Some may see it as easier to tune due to the factory widebands, which can trick you into thinking you're tune is close (since they constantly correct air/fuel), but in reality a proper tune is still needed. There are many changes to the logic in the PCM, so the old rules no longer apply. Overall I would say having a good tuner is now more important than ever."
"The 5.0 engine uses a new PCM with more complex software. The added complexity is required to properly characterize all the engine functions with the new Twin Independent Variable Cam Timing," Erin explained. "The tuning task becomes much more time intensive, as there are many different 'operating points' that need to be mapped and checked. High compression paired with a supercharger also presents unique challenges when mapping borderline spark and maintaining exhaust temperatures for catalyst protection."
"In the past, high compression did not go well with forced induction. It was unknown how the cars would respond to supercharging. Now that we've done it, we know it works great.
"Ford did its homework on chamber design, swirl, burn rates, and so on," Justin added. "The 5.0 can run on 87 octane from the factory and deals with boost well on 93 octane. It's surprising how much timing you can run on a blown 5.0 with premium gas in the tank. The out-of-the-box high compression means these cars need little boost to see huge power gains, this is good for overall efficiency."
Yet another curveball with the latest Mustangs is an all-new six-speed automatic transmission that takes its marching orders from Copperhead. Of course, not all new 5.0s are automatics, but Rebecca's is, so Justin also had to get up to speed on the trans tune, too.
"With six forward gears, a good auto-trans calibration is now more important than ever," he said. "Most cars will hit four or five of these gears going down the strip; when and how hard they hit vastly effects quarter-mile times. It's worth noting that this new trans can be calibrated to shift so hard, it side-steps four feet on the 1-2 if you aren't careful ... "
As you've probably already learned by now, the combination of Justin's tuning and Roush's supercharger system bestowed some impressive performance on Rebecca's otherwise-stock '11 GT.
We plan to try a few more things on this car, but for now, keep reading to see how this kit goes on. Roush provides comprehensive instructions, but unless you are an experienced wrench-bender, we suggest you take the job to a pro.
We've been waiting for this moment for a long time now, but boost has come to the Coyote 5
Since the Roushcharger is a fully engineered system, complete with heat exchanger, interco
Before making the jump to forced induction, Justin spent some quality time testing and tun
Way before you get to this step (you'll want to read those instructions before diving in),
After you've cleared out the fuel rails, heater hoses, and electrical connections, it's ti
There's plenty of room in the Coyote's valley for an air-to-water intercooler, but you do
Before you get out the grinder, you'll need to move the wiring harnesses mounted to the pa
It will be reused, but the inner belt that drives the air-conditioning can be cut off. It
Here comes the most daunting part of the install. It is necessary to trim three bosses and
Meanwhile sections of the ribs must be completely removed so that they are level with the
It is necessary to relocate some wires on both the throttle-position sensor connector and
Once you install the lower intake, you'll also need to install an air-charge-temperature s
Using existing fasteners, you mount the provided brackets for the Roush heat exchanger, wh
Likewise, the intercooler pump mounts using existing fasteners to secure this mounting bra
We had a slight delay with our lower intake manifold's arrival, so we soldiered on with th
Like the lower intake, this tensioner bracket is a signature piece of Roush's engineering
Before dropping the lower intake in place, be sure to install the new PCV purge hose to th
Lubing and install the new 47-lb/hr injectors in the new fuel rail before installing the w
We're almost home as Justin sets the Roush-charger TVS onto its matching lower intake. Sim
Here's the finished install. The new intercooler reservoir installs by drilling just one h
On The Dyno
| ||Stock||Roushcharger||85MM Pulley|
How's that for a gain from a single bolt-on? Adding the Roushcharger boosted Rebecca's otherwise-stock '11 5.0 by about 170 hp and nearly 140 lb-ft of torque. Better yet, the supercharger looks like it was factory installed, and Rebecca reports that the car drives better than stock.
Justin, of course, couldn't leave the car in as delivered form. He first tried a pulley 5mm smaller than the standard Roush pulley; then he bolted on an FRPP CJ throttle body. Both provided a small boost under of the curve, but only the CJ picked up the peak power by a handful. Justin firmly believes the stock airbox is the big restriction at this point, but he wanted to get the car into the 10s with a CARB-legal airbox, and Rebecca did just that.
We'll be following this car as Justin opens up the inlet and exhaust to see how much more the Roushcharger combination has on tap, so stay tuned.