There’s one modification that is sure to make power on an LS-powered vehicle, and that’s a full exhaust system. Fresh off the installation of a Roto-fab cold air intake , E85 kit, and custom tune by Cunningham Motorsports, it was time to install a full exhaust system on our 2017 Chevy SS.
The Chevy SS is the last of its generation performance vehicle to come with the tried and true LS3 powerplant. Like what’s found in its two-door cousin, the 5th generation Camaro, the SS has a lot to gain from a full exhaust install. Once again, we headed to Cunningham Motorsports for the installation of Kooks all stainless 1-7/8ths primary headers, GREEN catted 3-inch mid-pipes, and Kooks axle back exhaust. The specs on our kit:
1 7/8-inch to 3-inch merge stainless steel long tube headers
GREEN Catted X-pipe and mid-pipes
Kooks oval race mufflers and quad, 3-inch slash cut polished tips (works with factory mid-pipes too)
The great aspect of the Kooks exhaust system is that it’s is modular. Want to use the headers and X-pipe with the stock mid-pipes? No problem. Want to only upgrade the axle-back? You can do that too. Their American-made exhaust components are built with only high-grade, 304 stainless steel and are fully TIG welded. An added upgrade is Kooks mid-pipes that include Kooks EPA-certified (49 state legal) high performance GREEN catalytic converters.
The offset, slash cut exhaust system is polished to a mirror finish. The mufflers are made from an all stainless steel construction.The stock exhaust system does the job but is limiting our maximum power potential. The only downside was losing the factory dual mode exhaust functionality.Two bolts on each catalytic converter, two exhaust clamps at the axle-back, a few exhaust hangers and the mid pipes drop out.Two exhaust hangers on each side and the large mufflers drop out.After removing the coils, wires, and plugs, the factory exhaust manifold bolts are easy to access with an air ratchet.The difference here is pretty obvious. The factory catalytic converters that are normally affixed to the downpipe will be replaced with GREEN cats in the Kooks X-pipe.The funniest part of any exhaust install, snaking in the long tube headers! The SS engine bay is fairly painless. We only needed to disconnect the steering shaft to install the driver’s side header.Both headers mounted in place. Make sure to install the primary O2 sensors into the headers before installing the headers. Also, it’s always best practice to use fresh exhaust manifold gaskets.The catted X-pipe mounted loosely in place. The factory under brace helps hold the piping in place. Keep all the hardware lose to allow for easier adjustment.The mid-pipes are a two-piece design with one exhaust hanger on each side.Just like that and the exhaust is hung. Now situate the exhaust piping so it doesn’t rub on anything and tighten down all the clamps.Sitting pretty! Now it was time to get the SS on the dyno to see how much power we picked up.Coming into the exhaust install we already established an E75 optimized tune with a Roto-Fab cold air intake on Cunningham’s Mustang Dyno. Those numbers came in at 379.0 horsepower and 364.5 lb-ft of torque. After further optimizing the ethanol tune for the Kooks header-back system, final numbers cracked 400 horsepower and 384.2 lb-ft of torque. A total increase of 21.2 horsepower and 19.6 lb-ft of torque! Respectable gains on a Mustang Dyno! Next up? An LSA supercharger upgrade.
