Lethal Performance opens up the exhaust on its new GT project with a full system from American Racing Headers
By Steve Turner
Photos courtesy of Lethal Performance
If you have been following the progression of Lethal Performance’s 2015 Mustang GT project car, you know things have gotten serious in a hurry. From basic bolt-ons, right into nitrous, the car is on the fast-track to being fast. As part of that transition, the car has seen numerous bolt-on exhaust upgrades, as the Lethal camp likes to try out the parts it sells.
For its 2015 Mustang GT project, Lethal Performance chose American Racing Headers’ 2015 Mustang GT 1-7/8×3-inch off-road X exhaust system with Pure Thunder Mufflers (PN ARH-MTC5-15178300FSNC; $2,869.00). They offer 1 3/4-, 1 7/8-, and 2-inch long-tube headers and collector sizes up to 3 1/2 inches to fit anything from a daily driver to an all-out race car. These systems can be had with an H- or X-pipe and with or without catalytic converters.
With the next big move looming—the addition of a Whipple supercharger system—it was time to get serious about opening up the exhaust. While the combination of the Lethal Performance resonator delete and several different cat-back systems certainly helped the cause, there is no substitute for a full exhaust system fronted by free-flowing long-tube headers.
“We’ve been using American Racing Headers on all of our project cars and trucks for many years now so we figured there’s no reason to fix something if it isn’t broken,†Jared Rosen of Lethal Performance said. “Their systems are made right here in the USA by a bunch of great guys that are just as enthusiastic about racing as any other gearhead across the planet. Plain and simple, ARH it is!â€
Team Lethal headed over to Power by the Hour in Boynton Beach, Florida, to have the system installed by Jesse Guajardo. He removed the stock and aftermarket gear and bolted up the new American Racing Headers’ system on the Lethal GT without a hitch. The system looks great, and sounds even better.
Jesse Guajardo of Power by the Hour in Boynton Beach, Florida, begins by removing the entire cat-back system. Though the monolithic S550 exhaust system requires cutting to install an axle-back system, when you are replacing the whole system you can unbolt it and remove it without having to wrestle it over the axle.
“Just like any of the other ARH systems we’ve used the fit and finish on their 2015 Mustang kit is exactly what you’d expect from a leader in the aftermarket exhaust industry. They use high-quality T304 stainless steel and have stacked-dime welds wherever a weld is needed,†Jared said. “This was actually the first time we’ve ever used one of their complete systems. Typically we would mate their headers and mid-pipe with a Magnaflow competition exhaust. However Nick Filippides at ARH was persuasive about having us run their complete setup from headers to tips saying the system sounded amazing. So we trusted him with that recommendation.â€
In preparation for removing the K-member, Jesse disconnects the steering linkage.
Of course, the installation was only part of the process. With the American Racing 2015 Mustang GT 1-7/8×3-inch off-road X exhaust system and Pure Thunder Mufflers (PN ARH-MTC5-15178300FSNC; $2,869) in place, Lethal hit the dyno to document the results.
“What’s not to love about making more power and sounding awesome at the same time,†Jared enthused. “That’s exactly what we got after installing their complete system. I’m definitely impressed and glad that we went this route. Thanks again to our friends at ARH for another job well done!â€
We are still catching up on some of the other mods on this car, so stay tuned for more stories. However, the next major mod is the aforementioned Whipple supercharger. It will really take advantage of the improved exhaust flow. Until then, enjoy the installation of the full ARH 2015 Mustang GT exhaust system.
With the radiator and engine properly supported, Jesse unbolts the K-member. Doing so allows for unfettered access to the factory manifolds.After clearing a path, Jesse unbolts the stock manifolds and catalytic converters.Jesse then laid out the new American Racing Headers system on the floor in the same order that he would install it.Before proceeding with the install of the new parts, Jesse removes the factory starter to gain a bit more room to maneuver the long-tubes into place.Fits like a glove. Jesse slides the ARH long-tubes into place and hand-tightens the fasteners. Once the header is secured he torques the fasteners to the factory specs.It’s easy to see how the ARH long-tubes outflow the factory manifolds and catalytic converters. With the headers in place, Jesse reinstalled the K-member and reconnected the steering.Then Jesse swapped over the stock oxygen sensors to the ARH headers.In deference to its mission on the drag strip with big boost, the Lethal car was fitted with the cat-less ARH system. These long-tube-to-X-pipe adapters are available with and without catalytic converters.Lethal opted for the complete system with the X-pipe, but ARH offers a long-tube system compatible with aftermarket cat-back systems. It features the company’s Bottle Neck eliminator, which provides a 3-inch connection to the cat-back, rather than the 2 ¼-inch connection designed to mate with the factory exhaust.A jackstand supports the X-pipe as Jesse connects the extension pipes to the X-pipe.Jesse continues by installing the ARH Pure Thunder Series axle-back system with the tailpipes first.He wrapped up by clamping on the mufflers and exhaust tips. With the system installed and the clamps loose, Jesse could adjust the system and check for proper clearances before final-tightening the system. After a test drive to ensure there were no leaks, Jesse re-checked the clamps and the car was ready to hit the dyno.With a JLT cold-air intake, a custom tune from Lund Racing and a stock exhaust augmented by a Lethal Performance resonator delete and a Roush axle-back system, the Lethal GT put down baseline numbers of 408.45 horsepower and 389.97 lb-ft of torque. With the addition of the complete ARH exhaust system, the car generated peak-to-peak gains of 26.11 horsepower and 13.88 lb-ft of torque.We enjoy taking a look at selection of the dyno data in chart form because it often points out some of those under the curve surprises you might not notice in the graph. However, in the case of the full American Racing Headers’ exhaust on the new-school Coyote, there are no real surprises. The more you rev the car, the more it likes the freer-flowing exhaust.
