Heavy Breathing
Improve breathing on your new Dodge Challenger with A Mopar® Cat-Back™ exhaust and cold air intake.
Story By: Maurice Q. Liang
Editor’s Note: Maurice Liang is an active member of the Viper Club of America (VCA) and frequent contributor to VIPER Magazine.
Powerful, smooth, comfortable—with retro-styling done right—the new Challenger is a great all-around package. The only thing missing from this modern muscle car experience is the good old American V8 rumble. To meet drive-by noise regulations, Dodge had to hush the exhaust note to an extent.
To give the Challenger a more authoritative voice that would live up to its looks, I decided to install the Mopar® Cat-Back™ exhaust. As a bonus, it’s an easy way to bump up horsepower a bit, too. And who’s going to turn down more power? The exhaust, Mopar part number P5155151, carries an MSRP of about $1,600.
Quality Matters
Why choose Mopar’s Cat-Back exhaust? Because I expected Mopar to deliver a high quality product—up to Original Equipment standards—with an easy installation. I wasn’t disappointed. Mopar’s Cat-Back system uses T304 aircraft quality stainless steel tubing for longer life. It’s a bolt-in installation, so no welding is required. And you get the really cool exhaust tips, too. They’re rectangular with a split down the middle, just like on the 1970 Challenger, and they have “Mopar” etched into the top.
What You Get
The Mopar exhaust comes with an x-pipe, left and right axle pipes, connecting clamps, and left and right mufflers. Hangers are pre-welded to fit O.E. mounting points.
Do It Yourself
While Mopar recommends installation by a professional, it’s certainly possible for the DIYer to install the system if you have a hoist or jack stands and some basic tools. Because of its size, you will need an additional person to help with the removal of the stock system and the alignment of the new system.
The instructions are very clear, and the installation process went amazingly well. Rather than repeat the instruction sheet, I’ll just give an overview of the process and any “gotchas” that we encountered.
Raise the car up on jack stands or a hoist so you can move around easily under the car. Removal of the stock exhaust system is fairly easy, particularly since the Challengers are still new, and thus clean and rust-free.
The stock exhaust is removed from the catalytic converter back by unbolting the factory connector. The factory exhaust comes out in two pieces. First you remove the driver’s side rear section. Then, the rest of the exhaust system, from aft of the catalytic converter, all the way back to the passenger side exhaust tip, comes out as one (heavy) assembly. You’ll need to reuse the factory hangers and grommets.
The tools necessary are in any home mechanic’s tool box: metric wrenches and sockets, a 12" ratchet extension, a ratchet, and a torque wrench. A pair of channel locks will work for pulling the grommets off the hangers if you don’t have an official “grommet puller.” The entire process took about 4 hours.
Gotchas
As mentioned, the instructions were pretty clear. A few tips we’ll pass along from our installation experience:
LEFT AND RIGHT: The left and right axle pipes look similar, but are different. The left, or driver’s-side pipe was marked with a green dot while the passenger-side pipe had a red dot.
SHIPPING DAMAGE: When one of the pipes on the rear muffler wouldn’t slide on, we noticed it had been flattened, most likely during shipping. We just carefully bent the end of the pipe back to a circular shape using an adjustable wrench.
ALIGNMENT: The trickiest part of the installation was adjusting the new exhaust system so the exhaust tips are level and centered. This is where it helps to have an assistant or two. As the instructions suggested, we left all the clamps just snug, so everything could be moved around during the final fit. We used a prybar on the x-pipe to rotate the exhaust while someone watched the rear tips until they were level and centered in the openings. While two of us held the tips in place, a third person tightened the clamps (Mopar recommends NOT using air tools for this).
Results
Under acceleration with the new exhaust, the Challenger sounds like a NASCAR race car going by. Blip the throttle, and it has a bit of a bark to it. While cruising on the freeway, the exhaust is barely perceptible. Under partial load, there’s a bit of a drone, which is tolerable, though if it were a lot louder, it would probably become irritating.
Though louder at idle than the stock system, it still doesn’t have the burble of a ’70 Challenger. To get that, you’d have to leave off the exhaust from the catalytic converter back (It sounded great when we had NO exhaust attached). However, I’m told at cruising speeds, the sound level would be intolerable.
The guy at the local muffler shop, who has installed numerous aftermarket and custom exhausts on Chargers and Mustangs, said the tone and the quality of the Mopar system was superior to the systems he’d seen.
Using the Challenger’s built-in performance timer, the new exhaust seems to shave a tenth or two off the 0-60 mph time, though the biggest problem now is getting the tires to hook up!
Cold Air
Mopar Cold Air Intake Kit
As long as I was looking for easy power improvements, I installed Mopar’s cold air intake kit. Though Mopar makes no specific horsepower improvement claims, similar aftermarket systems claim an improvement of 21 horsepower. The kit, part number 77060006AB retails for $369, and replaces the stock air intake box and filter with a low-restriction cone filter and a straight pipe. The air intake temperature sensor is retained from the stock intake.
Installation is straightforward and takes about an hour. Basic hand tools are all that’s necessary—screwdrivers, metric wrenches and sockets. You’ll remove the entire air-intake system as one unit, and then piece together the cold air kit as you install it. All the parts fit well. While the instructions are fairly clear, here are a few tips we’ll pass along.
HOSE CLAMPS: Be sure to use the smaller hose clamp to attach the small end of the rubber “L” hose to the throttle body. The larger clamps will work here, but the small clamp won’t fit the larger hoses later.
INSTALLING THE CONE FILTER: To make it easier to attach the cone filter to the intake pipe, it helps to move the black filler tank located on the front of the coolant overflow tank. Simply bend the locking tab sideways and lift up on the black tank. Once the filter is in place, then slide the black tank back in its slot.
CRANKCASE BREATHER HOSE: The hose provided may need a little trimming to fit correctly between the intake tube and the manifold. However, be sure to leave a little extra so the tube/hose can bend around the plastic valve cover.
INSULATION RUBBER: My kit included a piece of rubber trim that looks like it should fit on the edge of a metal piece. No mention of it was made in the instructions, but I presume it was to fit on the top edge of the mounting bracket to seal off the cold air filter from the engine compartment when the hood is closed, so I installed it along the top edge of the bracket.
NUT & WASHER: The instructions tell you to install one side of the rubber isolator using a flange nut and washer, but there’s no instruction to install the second nut flange and washer when attaching the mounting bracket. It’s pretty obvious, but don’t forget to do it!
Results
With no dynamometer to measure the power gain, I could only judge the difference by the seat of my pants. It’s hard to say if there was an improvement in acceleration, but the tires do seem to break loose even more easily than before. Noise levels aren’t noticeably different.
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Reply #1 on : Tue March 24, 2009, 11:05:00