Preview: Building A ROUSH RS3 the StangTV Way

Last fall we spent time with the ROUSH Performance RS3 and reviewed the car. The factory street fighter and track contender comes with 575 hp in it’s Phase 1 trim. It is also a limited production vehicle, destined to one day be a collector’s car, making the thought of purchasing and modifying a RS3 somewhat unnerving.

We decided to construct our own version of the RS3 the way some of our readers might on their own. We’re planning to take on each modification one at a time and provide dyno and track figures as things change. Along the way we’re going to deviate from the standard RS3 and make a few changes, improving our car’s performance and matching our personal preferences. Our goal is running 10 second ET’s at the track and handling through the cones with some of the best out there on the autocross.

Our awesome, hand-drawn rendering was created by Jim Gerdom of Design Factory Art who also specializes in one of a kind, limited production art prints.

The Candidate

Our candidate for this transformation is a new 2013 Mustang GT. This car serves as a daily driver, and is also equipped with an automatic transmission.

With the car completely stock, we’ve already baselined it on our in house Dynojet at 351.67 hp and 348.88 ft-lbs of torque at the rear wheels. While we do intend to upgrade the car’s suspension and improve it’s handling, we also realize that the majority of our readers relate more closely to drag strip performance than track lap times. As such we’ve baselined the car stock at the local drag strip as well. Our best efforts at a recent test and tune night yielded an eighth-mile performance of 8.61 at 84.25 mph which equates to a 13.43 at 107.5 in the quarter-mile, which is on par for an automatic 2013 Mustang’s performance.

Baseline dyno results show 351.67 hp and 348.88 ft-lbs of torque to the rear tires.


At the eight mile drag strip we achieved a best of 8.61 at 84.25 mph which equates to roughly a 13.43 at 107.5 mph in the quarter mile.

Part 1 – Making Power

Our first upgrade will be a ROUSHcharger and a ROUSH axle-back exhaust system.

Phase 1 ROUSHcharger

Based on the Eaton TVS R2300 supercharger, this is the heart of the ROUSH Phase 1 supercharger upgrade. The Eaton TVS is a twin vortices supercharger with twin four-lobe rotors, which are twisted 160 degrees. This design features better thermal and volumetric efficiency over the older Eaton three lobe design.

Also included are ROUSH designed upper and lower intake manifold assemblies, twin 60mm throttle body with matching spacer, low restriction air induction system, high efficiency intercooler and heat exchanger, and 42 pound injectors.

ROUSH also provides a tune that is designed specifically for this upgrade. With the Phase 1 rated at 575 hp at the flywheel, we’ll verify how much is making it to the rear tires via our in house Dynojet.

We'll get things going in the power department with a Phase 1 ROUSHCharger and ROUSH axle-back exhaust.

Axle-Back Exhaust

We’ll also be installing a ROUSH 2013-2014 dual chambered axle-back exhaust system. Constructed from 409 stainless steel, with 304 chromed stainless tips, this system not only looks good, the materials also have the durability to last for the life of the car.

The chambered muffler design means there is no packing to wear or burn away over time, ensuring these mufflers will sound as good in a few years as they did the day we installed them. ROUSH has also worked diligently on the design of these mufflers to ensure that they don’t generate the drone or booming that can annoy and fatigue drivers.

ROUSH based the system’s dimensions and hanger locations on the original Ford CAD designs. This means the system can be installed with some basic tools in about an hour, without hanger modifications.

ROUSH Phase 2 Supercharger Upgrade

The final component of our part one upgrade will be stepping up our ROUSHcharger to a Phase 2 system. This upgrade is a simple bolt on that should take an hour or less for just about anyone to perform. The upgrade includes a new supercharger pulley, new serpentine belt, and updated tune. The major increases in power come from an upgrade to a larger diameter air induction system, featuring a 110mm mass air flow tube and open element air filter. An additional 50 flywheel horsepower is on tap with this upgrade, bumping power from 575 to 625 hp.

Our ROUSH Phase 2 upgrade will include a less restrictive air inlet, new serpentine belt, and updated tune.

Part 2 – Getting a Grip

With horsepower firmly squared away, part two of our StangTV ROUSH RS3 build will be a combination of ROUSH and Maximum Motorsports suspension upgrades.

Reducing the Hop

While the rear suspension on the S197 Mustangs is the best ever offered on a solid axle pony car, it’s not without it’s own issues. Wheel hop tends to plague these cars as horsepower increases. To remedy this we are planning to install a ROUSH revised upper control arm and bracket. ROUSH uses the same equipment as Ford to design their suspension components, ensuring not only quality engineering but also precise fit. This revised bracket when combined ROUSH lower control arm relocation brackets should give our RS3 better traction at the drag strip, and more stable cornering.

Wheel hop is a problem at the track even for a stock Mustang GT. We’ll get things a bit more under control with help from ROUSH and Maximum Motorsports.

Maximizing Handling

To further enhance the car’s handling we’ll be going with Maximum Motorsports’ soon to be released 2005-2013 Mustang Road and Track Grip Box.

This package includes:

  • Koni single-adjustable sport series struts and shocks
  • MM Road and Track springs
  • MM camber plates
  • Urethane front control arm bushings (*urethane bushings are optional)
  • Urethane rear swaybar bushings
  • New OEM strut-to-spindle bolts (Ford states these are one-time use only)
  • MM panhard bar
  • MM rear lower control arms— optioned up to Extreme-Duty series for this car’s power level
  • Front swaybar

Part 3 – Hoops and Rubber

We’re turning to Forgeline to provide us with a set of 20×10 front, and 20×11 rear wheels. We’ve talked about Forgeline wheels numerous times before. Our custom built wheels will be the SC3C design, finished in gunmetal and transparent smoke, which should blend nicely with the car’s ingot silver paint, while setting our RS3 apart from any others. Wheels will be massive 20 x 10.5 front, and 20 x 11 rear.

Our Forgeline SC3C with transparent smoke finish.


Mickey Thompson’s new Street Comp UHP tire is quickly becoming the hot ticket for high performance cars. We reviewed this tire not long ago, on Project Wild E Coyote. We’re so pleased with performance of the Street Comp that we’re putting a set on this car. With a 300 treadwear rating, and outstanding wet and dry performance, these tires should last for quite a while, provided we don’t wear them down doing some hard cornering. Tires will be size 275/35/20 at all four corners.

Grip will be increased by way of Mickey Thompson Street Comp UHP Tires.

Part 4 – Binding Force

Kooks long tube headers and Green catted X-pipe will help free up some additional ponies from our supercharged mill.

625 hp is great, but we’ll need a way to pull in the reins on our RS3. For that we’re looking to do some major braking upgrades as well.

We’ll be installing a big brake kit that will consist of 14 to 15-inch rotors at all four corners of the car, complete with six-piston calipers. We’ve installed a similar system on other projects and can confidently tell you that it takes Mustang stopping power firmly into super car territory, with stopping distances in the realm of cars that cost over four times as much as a new Mustang.

Part 5 – Longer Tubes

The stock exhaust manifolds just aren’t enough with power upgrades like we have for our RS3. To help us make some more power and remain emissions compliant, we’re turning to Kooks Headers and Exhaust for their long-tube headers and catted X-pipe. The headers we’re using feature 1.875-inch primary tubes and our X-pipe features 2.75-inch exhaust tubing. Constructed from stainless steel, and built by Kooks, we expect our exhaust upgrade to yield even more horsepower as well as a little more provocative exhaust note when combined with our ROUSH axle-back system.

Exhaust upgrades will continue with a set of Kooks long tube headers to go with our ROUSH axle-back exhaust.

Part 6 – The Look

With power and performance squared away, we’ll start making our car look like a RS3. To do this we’ll be installing a complete ROUSH body kit. The body kit will include:

  • ROUSH Spoiler
  • ROUSH Front Chin Splitter
  • ROUSH Upper Grille
  • ROUSH Lower Grille
  • ROUSH Side Splitters
  • ROUSH Hood Scoop
  • ROUSH Louvers
  • ROUSH Windshield Banner

A stock 2013 Mustang GT is not a bad looking car at all, but we're going to make things better with our ROUSH RS3 upgrades.

While we’re going all out on the exterior, inside the car we’re keeping things a little more sedate. We’ll be installing a ROUSH shift ball kit, and ROUSH door sill plates to help dress up things inside.

Part 7 – Bringing Up the Rear

With plenty of power production, and the car looking great, our build will finish with the rear axle assembly. When new, our automatic equipped GT couldn’t be ordered with the Track Pak rearend options from Ford. As such we’re saddled with 3.31 gears, not necessarily ideal for maximum performance.

An Eaton Truetrac differential will be able to handle street, strip, and auto-cross duties.

The final upgrade for our project will be a Detroit Truetrac rear differential from Eaton, and a Motive Gear 3.73 ring and pinion upgrade.

Customizing a Mustang to your personal tastes is the broad appeal of our hobby. We’re combining what we feel are the best parts from a variety of manufacturers to get an end result that should be both a drag strip and road course terror. This build is also being done in a manner that we feel many of our readers might conduct it, budgeting for each step individually and doing the upgrades over time. We’re looking forward to bringing this build to you, and excited to get started on it.

About the author

Don Creason

Don Creason is an automotive journalist with passions that lie from everything classic, all the way to modern muscle. Experienced tech writer, and all around car aficionado, Don's love for both cars and writing makes him the perfect addition to the Power Automedia team of experts.
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