In our never-ending quest to expose our readers to the hottest, most durable, high-performing car parts, we’ve decided to take on yet another project car. This time it’s Project Silver Bullet, a 2013 Mustang GT that will be subjected to a whole host of automotive performance parts over the course of its lifespan. In this article, we’ll tell you all about the first round of modifications to our GT and even do some track and dyno testing to prove out the worth of those performance upgrades.
Part one of the project centers around our installation, dyno tuning, and track testing of the ROUSH PerformanceR2300 Supercharger Kit for 2011-14 Mustangs [PN 421388, $6099.99] in Phase 1 form. With the Phase 1 kit, we’ll be hanging a ROUSH Performance Axle-Back exhaust [PN 421127, $489.99] and then upgrading to the Phase 2 Supercharger Package [PN 421389, $799.99], along with more dyno and track testing. As you might imagine, all of this testing is quite intensive, but we want to be able to bring our audience the most comprehensive information possible on this group of upgrades to Silver Bullet.
Getting the CARB Approval
“The closed airbox that comes from the factory with the 575 hp kit retains the hydrocarbon paper inside, and it was very important to retain that for 50-state-legal CARB approval. But when you go to the open element that the upgraded kit uses, there’s no way to trap the hydrocarbons that are bleeding back through the system. It shouldn’t matter, because you have the big compressor on top of the engine that should stop anything from coming back through the intake to the atmosphere, but CARB doesn’t look at it that way. They look at it as it’s not part of the original equipment on the vehicle,” says Velthoven.
One of the most important aspects to the ROUSH Phase 1 supercharger system is its 50-state-legal designation [CARB E.O.# D-418-22], critical for those who live in California - which just so happens to also be the residence of our project car. By carrying this 50-state-legal badging to go with the legendary ROUSH calibrations, the supercharger system will present us with zero issues when it comes time to hit the rollers for our California emissions sticker – a good plan for our brand-new pony car. Prior to ever making any changes to the car, we hit the track in completely stock form for a bit of testing on the machine and was able to click off a power-braked 8.61 eighth-mile hit at nearly 85 mph, roughly a 13.43 at 106 mph in the quarter-mile.
For this article, the star of the show is no doubt the ROUSH Performance supercharger system, based upon the proven Eaton Twin Vortices Series Rotor pack that’s proven itself to be a superb performer on the street and at the track. This supercharger is found on the 2014 ROUSH Stage 3 Mustang, and when we’re done with the installation on our machine we hope to equal if not better the RS3’s on-track performance.
The RS3 in Phase 1 trim is calibrated to deliver 575 hp and 505 ft-lbsat the flywheel, a solid 155hp and 115 ft-lbs over a stock Mustang’s 420/390 factory rating. These ratings are also on a manual transmission-equipped Mustang and our automatic will inherently produce a little less horsepower.
As a positive displacement supercharger, the R2300 offers immediate off-idle throttle response and boost, unlike a centrifugal-supercharged design that builds boost relative to RPM. Max boost is reached quickly and the system is designed to thunder all the way to redline.
There is a 3 year/36,000 mile warranty on the supercharger system parts, and ROUSH also offers a complete powertrain warranty option on the Phase 1 kit for an additional $375. The warranty period is 3 years/36,000 miles from the vehicle’s original in-service date. How’s that for service?
The Eaton Twin Vortices Series rotor pack consists of a pair of four-lobe, 160-degree-twist rotors that have become the industry standard, used in a number of different supercharger kits. In our ROUSH system they are good for 575 hp right out of the box.
Left - the lower intake manifold uses a slick intercooler built right into its base - a la the 2003-04 Mustang Cobra and GT500 variants of the last few years. Right - A large heat exchanger was also included in the system. This mounts in front of the factory radiator.
In addition to the supercharger, you also get a ROUSH-designed upper and lower aluminum intake manifolds, a high-efficiency intercooler system with a large, full-face low-temperature radiator, an oversized coolant degas bottle, air-to-water intercooler, and formed hoses featuring abrasion-resistant sleeving. A twin 60-mm throttle body is standard, along with a low-restriction air induction system, high-flow fuel rails including 47 lb./hr. injectors, and a bolt-on, 85mm supercharger pulley. All fasteners, brackets, additional wiring, custom-formed hoses and clamps are also included in the kit.
The Eaton supercharger itself has a pair of four-lobe rotors that are twisted 160 degrees, which, when combined with ROUSH Performance’s own design for the air inlet and outlet ports, means that ROUSH claims thermal efficiency and volumetric capacity is improved. ROUSH Performance’s Jay Velthoven explained, “We use the proven Eaton TVS rotor pack and we engineer everything except for the core rotor assembly. The housing, the intake, the cooling system, everything else is engineered here. Eaton’s been building those for a long time and they are the best at doing it. As an OE supplier they can offer the technology to us to where it makes sense to produce the kits.”
Left - This boss, along with one other on the timing cover, needs to be modified for clearance for the supercharger's belt-drive system. Right - Our spark plugs were swapped for the set that came in the package; they are one heat range colder than stock.
ROUSH claims a 10-hour installation time, and we’re inclined to go along with that. One thing that will derail your progress however, is the fact that the PCM needs to be removed from the car and shipped out to the tuning wizards at ROUSH for a tuning reflash to accommodate the new fuel injectors and increased power output. This puts a kink in the install time, but it’s the way ROUSH is able to achieve the 50-state-legal designation on the supercharger system. They provide the FedEx box and label to make that a reality, but it will cause the car to be down for a couple of days while the PCM goes out and back. Thankfully, the peace of mind in knowing that you’ve got the ROUSH engineers behind the tune on your new supercharger kit, and the car won’t exhibit any bucking, popping, snorting, or fail emissions no matter where you live makes it well worth the wait.
Our PCM tuning is the closest thing to an OE-style calibration that you can put into your car - Jay Velthoven, ROUSH Performance
“We utilize a system that’s a bit more in-depth than a hand-held tuner. We dive deeper into the calibration system, and touch a lot of the systems that you can’t get to with the aftermarket tuners. Our PCM tuning is the closest thing to an OE-style calibration that you can put into your car. We’re using more of a OE Ford-type tool. It’s also very important for quality control, and we’re very conservative. We want to make sure everything is as if you got it from the factory,” Velthoven said.
Left - We needed to remove the front fascia as the very first step in the disassembly process. Once you pull out a few fasteners in the inner fenderwells you can access the fascia's fasteners. Right - Our processor was removed before we started the install, and ROUSH Performance was kind enough to send a prepaid box to send it back for reflashing.
Installing The Parts
We are starting with a blank canvas here – save for the previous installation of a K&N Filtercharger kit, this car wore all of the stock components before we set out to make it into a ten-second strip monster and autocross slayer. Lead Power Automedia technician Sean Goude’s first order of business, of course, was to read the super-thorough directions that are included with the supercharger system. The next step was to disconnect the battery, as we needed to remove the PCM and send it off to ROUSH to be flashed.
From there, it’s time to remove the stock intake manifold. This process is no different than any other car you’ve ever worked on, and since many of the attendant components were getting replaced with the supercharger system Sean opted to remove it as a single assembly, making the process much easier. A couple of vacuum and coolant lines are removed, then the manifold fasteners themselves, and it’s time to set the assembly into the corner of the garage, possibly to never be seen again.
Left - There are some wiring tasks that need to be performed, namely the power and ground for the intercooler pump. Sean pulls the wires from the factory connectors to achieve the finished product. Right - It's easiest to install the new 47 lb./hr. fuel injectors on the bench into the new ROUSH-provided fuel rail assembly. A dab of lube on all of the o-rings simplifies the process and keeps dirt out.
Once the manifold is out of the way, it’s time to really dig into the meat of the project. First off is the installation of the heat exchanger, which plugs right into the factory coolant lines thanks to the well-engineered new parts from ROUSH. The new supercharger kit shows up with two main pieces – the lower manifold assembly and the supercharger itself. Of course you all of the other attendant gear like fuel rails, throttle body, and injectors, but the bulk of the system is the two main pieces. Overall this is one of the simpler supercharger system installations we’ve worked with. Follow along with the photos and captions to see some of the more intricate parts of the install.
All finished with the Stage 1 system - it looks factory-installed, which is the the main appeal of ROUSH’s supercharger systems.
Getting The Unleaded Out
The second section of our upgrade started with a pair of stainless-steel mufflers, the ROUSH Performance Mustang Exhaust with Round Tips, part number 421127. Unlike most of the Mustang aftermarket’s performance mufflers which feature fiberglass-packed mufflers, the ROUSH system uses an open-chamber design, which has a number of advantages for the end-user.
Specifically, the open-chamber ROUSH Performance muffler on the new 5.0 engine found in the Mustang produces a unique aggressive sound, and thanks to the lack of fiberglass packing, will last for a long time since there is no packing to break down. Reducing back pressure also means that they permit increased airflow, a good idea in our case since we’re increasing the engine’s power output by one-third. The mufflers have been engineered to sound great, and an added benefit of the open-chamber design means that there’s no highway drone in the cabin, a sound that Mustang owners know all too well.
The ROUSH Performance Axle-back muffler kit added a nice aggressive tone to the car, one we’re very happy with. It fits right into the stock hangers and installs in about an hour.
The mufflers install in the stock hangers, meaning a minimum of muss and fuss during installation.
The mufflers and piping are built from 409 stainless steel, while the tips are built from 304 stainless steel. ROUSH uses a unique chrome-flashing process on the exhaust tips, which is bonded microporously to the metal surface and won’t crack. It’s also resistant to color change from heat buildup. The system carries a three-year warranty, uses the factory muffler hangers, and includes new OE-quality spherical clamps. It takes about an hour to disconnect the old mufflers and install the new system.
On our in-house Dynojet we ran Project Silver Bullet to see what our Phase 1 upgrades had netted before heading to the track. We had previously baselined the stone-stock automatic at 351.67 rwhp, and 348.88 ft-lbs of torque. Our efforts were rewarded with 469.54 rwhp and 402.58 ft-lbs of torque. It’s a gain over stock 117.87 rwhp and 53.70 ft-lbs to the rear tires. This nearly matches the claimed horsepower increase from ROUSH if you factor in a 20% drivetrain loss.
Phase 1 Track Run
On The Track – Part 1
As you can see from our track test in the above video, performed after the Phase 1 supercharger kit was installed, we got the best performance out of the car by leaving the starting line right at idle, rather than revving the car up and attempting to leave harder. Car owner/driver Melissa Lawrence hadn’t been down the dragstrip in about three years, so with time and practice she would have been able to better those numbers, perhaps even slipping into the 11-second range. For this portion of the test, the car retained the stock 245/45/18 tires and 3.13 rear-end gear ratio.
The car still managed a 1.90 sixty-foot time and a 7.88 at 92.26 mph in the eighth-mile. That equates to about a 12.13 at somewhere around 114.9 mph in the quarter-mile, achieved with the stock six-speed automatic transmission. The car picked up 1.23 seconds and 8 mph on the stock suspension and tires!
Adding More Power
Now it’s time for us to install the ROUSH Phase 2 Supercharger Upgrade Kit, part number 421389, which we detailed in a previous article. The simplicity of this system is magnified when you realize what it gets you – a whopping 50 hp, 20 ft./lb. increase with no other changes to the car. It includes all of the pieces for installation and upgrades all of the 2011+ ROUSH supercharger systems from their 525 hp kit, through the 540 and the 575 hp kit we’ve previously installed. In our case it should bump flywheel output to 625 hp and 525 ft/lbs!
The slot-style mass airflow sensor gets removed and installed into the new tube. The Phase 2 kit includes an open-element air-filter as well as a baffle to prevent sucking in hot underhood air.
The kit includes the 85mm supercharger pulley (for owners of the 2011-12 supercharger system, which has the larger pulley initially), a brand-new 6-rib serpentine belt, and the star of this part of the show, a ROUSH cold-air induction system with 110mm MAF tube, larger clean air tube, open airbox, and re-usable performance air filter.
In addition, the PCM needs to be modified again to provide an updated calibration, and ROUSH includes the box and shipping label for this as well in case you’re upgrading from a previously-installed system. Essentially on our 2013 Mustang, we will only be installing the cold air intake and new tune.
ROUSH tests all of their supercharger systems, spending hundreds of hours researching and testing parts and pieces to make sure that everything works properly for the end-user. Products are tested from -20 degrees all the way up to 120 degrees Fahrenheit just to ensure that the parts will work in any circumstance. So if we decided to go drag racing in the bottom of Death Valley, the ROUSH parts will hold up. They even test the parts up to 14,000 feet of altitude, meaning that those of who live in Denver, and even atop Mount Rainier, still won’t have any issues with the parts purchased.
The Phase 2 cold air intake and new ROUSH tune netted 497.39 rwhp and 410.84 ft-lb to the rear tires.
The engineers at ROUSH have the ability to perform emissions testing, and the upgrade kit has had over 40 tests to ensure that the car retains the same emissions as it does with the Phase 1 system, but the upgrade kit is not CARB-approved at this time. However, the engine diagnostics still work as designed by Ford, and the time the ROUSH engineers spend on the dynamometer allows them to re-map the camshaft positions and many other aspects of the calibration to ensure that the vehicle still drives just like it did the day we picked it up from the dealership – but with an added 205 horsepower.
On The Track – Part 2
After the Phase 2 upgrades were installed, it was time for more testing. On the dyno we showed a solid 497.39 rwhp and 410.84 ft-lbs of torque. The difference in power from Phase 1 to Phase 2 would seem to be right in line with what ROUSH has advertised. To the rear tires we gained 27.84 rwhp, and 8.26 ft-lbs of torque. At the track our Phase 1 timeslip shows an approximate 12.13 elapsed time, and the addition of the Phase 2 upgrade offers a marked improvement in performance on the strip.
As you can see from the timeslip to the left, we were able to crack off a stout 11.88 at nearly 120 mph.That’s an improvement of just over 2.5-tenths and 5 mph at the track from the addition of arts that can be bolted onto the car in a few hours time.
One Step Further with a Brenspeed Custom Tune
We found no difference in drivability, a testament to the extensive PCM remapping from the ROUSH engineering team and the well-engineered supercharger kit. But even as ROUSH stated, the dyno tuning is extremely conservative so that they can conform to CARB standards along with their optional engine warranty. One aftermarket tuner that probably has some of the most seat time with the ROUSH supercharger is Brent White of Brenspeed.
“Our calibration is designed for more power, and is specific to each customers vehicle and list of modifications including octane fuel,” said Brent White of Brenspeed. “Power and torque though are only part of the improvement equation, even parameters like speed limiters and rev limiters are modified to give you more of a performance feel. Automatic transmission owners can benefit from modified transmission functions and manual transmission owners can enjoy an eliminated skip shift function of they choose.”
While horsepower numbers stay the same with the Brenspeed tune, we picked up nearly 30 ft-lbs of torque to the rear tires.
Another limiting aspect of any manufacture-supplied tune on a force induced Coyote is the catalytic converter over temperature failsafes. This function is designed to do specifically what it says - limit the ability for the catalytic converter to overheat, but for a drag racer, it equals less than optimal performance. As the Mustang accelerates down track and exhaust gas temperatures increase, the PCM will force the tune to run considerably richer. While we might have been making 497 hp off the line, that number is cut down significantly as we head through the traps. These short blasts down the track probably won’t have an adverse effect on the catalytic converter’s life, though if you do plan to road race your vehicle, leaving this failsafe active might be a good bit of insurance.
We dropped over one half a second off our eighth mile time with better traction, updated tune, and a more aggressive rear gear ratio.
To aide traction we mounted a pair of Mickey Thompson ET Street Radial II 265/40/18 tires on some OEM rims.
Providing the link between the Brenspeed tuning and our 2013 Mustang is an SCT Performance iTSX. Brent emails us the tunes, which we download directly into our iPhone, making the tuning process virtually brainless.”Since the beginning we have always invested in engineering vehicles and at times, a lot of them,” says White. “We use them to really put our packages through the paces not only on the street but just as important at the strip. It is very expensive to do this but in our opinion, it is the only way to provide a validated calibration through mail order and in house. We currently have five in house vehicles running multiple different power levels of ROUSH superchargers.”
In addition to the Brenspeed tune, we upped our rear gear ratio to a 3.73 (which you will read in a future article) and added a set of Mickey Thompson ET Street Radial II 265/40/18 tires to a set of OEM 18-inch five spoke Mustang wheels. The ET Street Radial II was designed with modern performance cars in mind, especially those that feature larger brakes, which make it necessary to run a larger diameter wheel. The ET Street II features MT’s R2 rubber compound. Radial construction and DOT approval means we can run this tire safely and legally on the street. At the track, we can drop the pressures and like MT’s other ET Street Radial products get these tires hot and ready to hook.
Our first time back to the track netted us an almost immediate boot off the race track since we don’t have a roll bar in our Mustang yet. On the third pass of the night, we went 7.22 at 97.93 mph, three hundredths faster than we are allowed to go without a cage. This means our ‘Stang has the capability of running 11.11 at 126mph in the quarter mile. We are certain with a little tweaking on tire pressure and launch RPM, a 10-second slip is very possible. The car pulled an impressive 1.6 sixty foot time. This is in large part due to the extra bite from ET Street Radial II’s, something that previously was difficult to do with a an 18-inch wheel/tire combination on a car such as this, we can say confidently that the 60-foot time would not have been possible without the use of these tires.
A worthy first-round upgrade to our 2013 GT - which is slated for much more, as you can see in our preview article. There are a host of upgrades yet to come, but with this first step in our project we feel comfortable that we’re well on the way to turning this car into a fine example of the breed - that is comfortable in any environment.