To squeeze some additional horsepower from the boxer engine in my Scion FR-S, I knew an exhaust manifold was in order. So far power mods for the 4U-GSE have included an HKS intake, Tomei straight pipe and Tanabe's Concept G single exit exhaust. For the header, I reached out to DC Sports and inquired about its equal length exhaust manifold; I could've gone with an unequal length header, but I was more interested in power gains than just copying that Subaru rumble. It's been proven equal length headers are far superior to their unequal length counterparts in terms of performance and response, plus it's a relatively inexpensive modification.
The DC Sports race header is constructed of T304 stainless steel and fully polished for a show-quality finish. The 4-into-1 design increases flow and exhaust gas velocity to increase top end power. Our friends at Auto Tuned helped install the exhaust manifold, while Raceline USA handled the dyno session.
We began by finding a flat work area where we could raise the car. We lifted up the FR-S, making sure to use jack stands under the front frame support joints; you can refer to the owner's manual to find these points. In order to access the OEM exhaust manifold, we had to remove the aluminum splash shield under the car by removing eight 12mm bolts, four 10mm bolts, and seven plastic clips that secure the shield. We then had to remove the six 10mm bolts that secure the black fiber splash shield to the chassis. We unclipped and unplugged the two primary and secondary O2 sensors from the vehicle wire harness. We then found two 14mm bolts that secure the manifold to the overpipe.
Next we removed the six 14mm nuts that connect the manifold and engine. We then had to transfer the two O2 sensors that were found in the OEM header onto the DC unit and then reinstalled and buttoned up everything back into place.
Once the dyno rollers stopped at the end of the day we saw a five horsepower gain and a microscopic .2 torque loss. I'd be lying if I said it didn't sound like a Honda, but I'll gladly take it for the performance value. For maximum gains, DC Sports recommends tuning the car with the manifold, but it's not required. The MSRP is $725.00 and you can find it at www.dcsports.com.