After Getting Project MILF...
After Getting Project MILF to ingest volumes of air with the FRPP Super Pack, we decided it was time to let the car exhale through a full-on Stainless Works exhaust system.
It's a pretty simple philosophy: What goes up must come down, and what goes in usually comes back out. In automotive terms, when you put more in (meaning air/fuel mixture), you usually get more horsepower out. That's what we had in mind with Project MILF.
If you recall, we took a Ford Racing Performance Parts Super Pack and put it on our '06 Mustang GT project car. The resulting boost from the Whipple supercharger lofted our mighty Three-Valve's rear-wheel power and torque numbers to 335 and 308, respectively. But that was only the beginning. Knowing that the blower was pumping in a higher volume of air, we wanted to upgrade the exhaust system to get the combusted mixture out of the cylinders quickly and effectively. That's why we decided to give Project MILF the works.
We dialed Stainless Works and ordered a pair of stainless steel long-tube headers along with a stainless steel after-cat exhaust system. The headers we installed were of the 1 3/4-inch primary tube variety, and they empty the exhaust gasses into 3-inch collectors. Included with the headers were high-flow cats and mid-pipes, front and rear O2 sensor extensions, and adapters to fit the 3-inch collectors to the 2 1/2-inch factory exhaust tubing, should we have chosen to do that. Of course, we didn't. Backing up the headers would be Stainless Works' 3-inch after-cat system, which showcases two high-flow mufflers, polished rear tips, a custom x pipe system, and all the hardware needed to make it fit like stock.
Before We made headway with...
Before We made headway with our exhaust upgrade, we put Project MILF on Crazy Horse Racing's Dynojet chassis dyno to get some up-to-date baseline numbers. With the FRRP-supplied Whipple blower whining, Project MILF cranked out 328 rwhp and 287 rwtq the day of the install.
One interesting thing about the system is that it was CNC-bent, so each one will fit the same way. An exhaust system's tubing is formed by one of three processes, those being pressure, mandrel, and/or CNC bending. Pressure bending involves placing a tube between a die and a hydraulic ram. The two are then pressed together, pushing the tube around a preselected radius, thus creating the bend. The problem with pressure bending a tube is that there's nothing inside of the tube to prevent it from collapsing or buckling. Not only does it look less than desirable with the bumps on the tubing at each bend, but inside, the corresponding rises impede flow. While this type of exhaust system is not great for performance, it's a quick and inexpensive way to equip vehicles with an exhaust system.
In response to the pressure-bent systems, the aftermarket developed mandrel-bent exhaust systems. To mandrel-bend a tube, a series of balls, known as mandrels, are inserted into the pipe when it's being bent. The balls are positioned and pulled through the pipe, thus supporting the tubing as it is bent. The smoother bends allowed exhaust manufacturers to make tighter radius bends. More importantly, with the tubing not being crushed, the system still flows well, even with the ability to bend the tubing to a tighter radius.
 We Took one more look at the...  We Took one more look at the factory exhaust system, which-for what it's worth-was a decent system. Soon, the factory mufflers and tips would be set aside for the looks and functionality of the Stainless Works after-cat system. |  Chris Winter of Crazy Horse...  Chris Winter of Crazy Horse Racing began disassembly by unclipping the connections to the O2 sensors. |  There are a total of four...  There are a total of four sensors. |
 The Headers from Stainless...  The Headers from Stainless Works are of the long-tube variety and measure 1 3/4 inches on the primary tubes and 3 inches on the collectors. In addition to the headers, the kit also came with high-flow cats, midpipes, and all hardware (except for header bolts). |  Next, Winter started taking...  Next, Winter started taking things apart by unbolting the head pipes from the exhaust manifolds. |  With the front of the system...  With the front of the system unbolted from the exhaust manifolds, Chris undid the clamps and hangers holding the stock H-pipe in place, and pulled the assembly down in one shot. He then moved out back and took out the stock mufflers and the tubing that went over the rear axle. |