Pro Dyno opens up the intake and exhaust of a new GT with great results
By Steve Turner
Photos courtesy of Pro Dyno
Ford is definitely on the right track with the fresh design of the 2015 Mustang. Rather than just preaching to the choir, the company sought to convert new Mustang enthusiasts with the modern styling and technology found in the latest pony car. That combo swayed Richard Sarver and his son Colby into choosing a new Mustang GT for a father/son project rather than a Suburu WRX. Nice choice, fellas!
The cornerstone of this swap is Stainless Works’ 1 7/8-inch long-tube headers (PN M15H-PRODUCTS; $1,490). Hewn from 304 stainless steel, the SW headers feature 3/8-inch-thick flanges and 3-inch collectors fitted with merge spikes. These headers join the SW cat-back exhaust via 3-inch lead pipes.
After ordering a Magnetic GT, they instead scooped up a Triple Yellow version that was in stock at a local dealer. Once you have a project car in hand, the next move is planning those mods, and the father and son team were soon eyeballing possible exhaust upgrades to give the GT some much needed bark.
“Colby knew that he didn’t want his car to remain stock for long, so they enlisted the help of Pro Dyno to find the right exhaust setup for it,†Jeremy Marler, Marketing & Social Media Manager, at Pro Dyno, said. “Richard and Colby had seen (and heard) that Stainless Works was working diligently on the new S550 exhaust systems and that is what they wanted!â€
Stainless Works’ 3-inch Chambered Round Cat-Back (PN M15CB-PRODUCTS; $1,125) for the 2015 Mustang is available as a Factory Connect for stock manifolds or a Performance Connect system for the company’s long-tubes. You can order this system with either an H- or X-pipe crossover, an either way this 3-inch system is based on SW’s signature Retro-Chambered mufflers and exits through polished, slash-cut tips.
As luck would have it, Pro Dyno was on the list to get one of the first production Stainless Works systems for the S550 GT. When it arrived, the Pro Dyno team got to work on the pristine new GT. The removed the stock exhaust, added a JLT Performance cold-air intake, and Pro Dyno main man Dan Desio worked his tuning magic to make the computer work with all the new parts and maximize their benefits.
“I just used the fundamentals that I used on the ’11-’14 cars, you just have twice the number of tables… Ford pretty much doubled all the tables—torque tables, variable cam timing tables, etc.†Dan explained. “They just added more ability for the computer to learn more, which should help the driveability.â€
To get an idea how the car sounds with the new Stainless Works system, you can watch the Sarvers’ GT run on the Dynojet at Pro Dyno and on the street right here:
Ready to become fast friends, the complete Stainless Works 2015 Mustang GT exhaust system was first on the list for Richard and Colby Sarver’s Triple Yellow beauty. They chose the full system with the X-pipe crossover and high-flow catalytic converters.
Clearly the results of opening up the intake and exhaust on the latest Mustang show that it still responds to the tried-and-true hot-rodding techniques just like its predecessors.
“Once the tuning was finished, it was a different car. It was night and day. Where you didn’t see it in the graph—the driveability—it was a different car,†Dan enthused. “From First through Third gear at about ¾ throttle it will break the tires loose without even trying to break the tires loose.â€
Sounds like fun to us…
To free up room to access the factory manifolds, the Pro Dyno team removed the strut-tower brace and factory induction. They also safely evacuated the air-conditioning system so those lines could be disconnected and moved out of the way. Then they could get down to loosening the fasteners on the factory motor mounts so the engine could be raised slightly with an engine jack to allow clearance for the manifolds’ exit and the headers’ entrance.Underneath, they removed the wideband oxygen sensors and before freeing the factory midpipe and cat-back from its connections.It is also necessary to disconnect the steering shaft and remove the starter to make a bit more room for the header install.Which system do you think flows better? The stock system with its variable-diameter piping, suitcase resonator, and integrated cat and manifold on the driver side seems wrought with restriction, while the complete Stainless Works setup (background) is ready to flow.With the factory catifold and manifold removed, the Pro Dyno crew bolted up the Stainless Works long-tube headers. You can opt to install the headers using the factory 10mm fasteners (eight per side) or use the provided fasteners. You can also re-use the factory gaskets and if you feel the need to augment them, SW recommends Permatex sensor-safe Hi-Temp RTV.After bolting up the long-tubes, the Pro Dyno team lowered the engine back down on the mounts and reinstalled the steering shaft and starter. Then it was time to clamp on the SW high-flow cats and the 3-inch lead pipes that join the headers to the SW cat-back. This is the Performance Connect configuration with the optional cats.Depending mainly on your exhaust-tone preference, you can choose between an H-pipe or and X-pipe crossover.The Pro Dyno team removed the factory cat-back and exhaust hangers, but kept the hangers and their fasteners at hand for re-use with the Stainless Works system. They hung the Stainless Works system in place with the factory hangers and loosely clamped the Retro-Chamber mufflers between the X-pipe and the tailpipes.After ensuring there is plenty of clearance between the exhaust and any vital bits under the car, the Pro Dyno crew aligned the 4-inch tips to the valance and final-tightened the system. You will want to drive the car around for 10 to 20 minutes then put it back on the lift to ensure there is still proper clearance and alignment before re-tightening the clamps. If you really want it to stay put, you can opt to have the connection points tack-welded.Wearing a new full exhaust, the Sarvers’ 2015 Mustang GT’s engine compartment was reassembled and augmented with JLT Performance’s cold air intake. We have extensively covered the installation and testing of this kit, so we know it works. Opening up the intake and exhaust at the same time is a sound strategy for a first round of modifications.Before the mods, Richard and Colby Sarver’s 2015 Mustang GT put down 379.81 horsepower and 364.24 lb-ft of torque at the rear wheels.With the full Stainless Works exhaust, the JLT cold-air intake, and a custom tune courtesy of Pro Dyno main man Dan Desio, the GT responded with 421.96 horsepower and 395.75 lb-ft of torque at the wheels, representing solid gains of 42.15 horsepower and 31.51 lb-ft or torque.
