Installing a Flowmaster Stainless Cat-Back on a 2010 Camaro

An exhaust – it’s the first modification that many enthusiasts make when they pick up a new car. It sets your car apart not only in sound, but also performance. Another great aspect of this modification is that an exhaust system is something you can switch out in your driveway in virtually no time. We installed a first production run Flowmaster Cat-Back on the most highly anticipated car of the twenty-first century – the 2010 Camaro.

If a vehicle is highly anticipated by consumers, you can imagine the mouth-watering excitement that comes from the aftermarket manufactures. It’s a race to see who can build parts the fastest, as consumers typically want to modify their Camaros even as they are signing the delivery papers.

The Car – 2010 Camaro – L99 Automatic

As stated above, the 2010 Camaro has received more hype than virtually any other twenty-first century vehicle. It has been nine years since GM developed the last Camaro, and with the latest model boasting Corvette horsepower for $30,000, it’s bound to be a hit.

The 6-speed version comes with an LS3 power plant that boasts 422 horsepower and 408 foot pounds of torque. For those who opted for the automatic version – like ours – the engine is changed to an L99 that produces 400 horsepower and 395 foot pounds of torque.

On top of the proven power is its unique look. Twenty-inch wheels tucked under aggressive rear box flares and accents that are reminiscent of the Camaros of yesteryear make this generation unique. The Camaro we have comes fully decked out with everything from leather to the factory body kit upgrade.

“Our R&D department has a good relationship with a local GM dealership and they were as excited as we were on getting something fit on both the V6 and V8 Camaros,” Cam Benty of Flowmaster tells us. “We were able to borrow vehicles from them and built the systems off them. This allowed both of us to benefit because now the dealership could sell the first Flowmaster equipped Camaro at their lot.”

“We got the first Camaro in April of 2009, so luckily we were able to get them pretty early,” states Benty. “We tried a couple series of mufflers like the Hush Power, but the muffler that fits that vehicle is a classic American Thunder Flowmaster product because of the legacy of American muscle cars, and that’s where Flowmaster has its strength.”

The Exhaust – Flowmaster 409S Stainless Steel Cat-Back

To complete yet another generation of Camaro exhausts, Flowmaster has released a stainless steel cat-back system for both the V6 and V8 versions. “Our kit was one of the first kits made and wasn’t even available to the public yet, so we were psyched to see how it was going to rumble on this brand new Camaro,” Benty tells us.

“We tried to create a careful balance of sound and resonance and we have stuck that. There is a lot upset these days with the resonance you get from high performance exhausts systems, so we made an effort to make a system that works with the vehicle. We look at the design of the underside of the car and make a system to complement that.”

The American Thunder 40 Series is the most aggressive sounding street and strip muffler in Flowmaster’s product line, and your dad might have had them on his ’68. The 40 Series creates a lot of interior and exterior exhaust resonance with its two chamber design. The rear axle back is painted black for a more stealthy look under the car and helps keep the cops’ eyes off your exhaust.

I asked Benty about a resonated version of the exhaust and this is what he told me: “We are finding that the Camaro owners want the more performance oriented exhaust with the current American Thunder version. There is the ability to modify if someone wants to, but at this point, this will be the only version we are going to offer.”

The exhaust piping is all 3-inch and uses Flowmaster’s 409S stainless steel. “We decided to do a 409 vs a 304 stainless due to the cost and need,” says Benty. “A lot of people want the durability of stainless, but don’t care about having a show car and don’t need the shiny 304. The 409 is actually more durable than 304.” You will find two 4” polished tips out the back end of the mufflers.

To keep the exhaust gasses happy and flowing in the right direction, look no further than Flowmaster’s Scavenger X-pipe, which channels the exhaust together to equalize pressure between the two engine banks. Additionally, the exhaust is covered under their 10-year limited warranty, as all their stainless exhausts are. The exhaust is a direct fit and includes all of the hardware needed to get it in the factory location.


• 409 stainless eliminates rusting and is more durable
• American Thunder 40 Series mufflers for maximum sound
• 4” polished tips fit in the factory location
• 3” mandrel bent piping
• Scavenger X-pipe equalizes exhaust pressures
• Blacked out rear mufflers for a more stealthy look
• Clamps are zinc coated ring style
• Utilizes all factory hanger mounts/locations for a true bolt-on application
• Increased interior and exterior sound level

Installing the Flowmaster American Thunder Cat-Back on the 2010 Camaro

Before starting the installation you must first remove the old exhaust. This installation can be done in your driveway in a few hours, but we recommend either the help of another person or at least two extra jack stands, since the stocker is one piece. Having a four post Benpack lift, we opted for the easier route and put the Camaro up on the lift.

The exhaust connects to the back of the catalytic converters with these cool slip fittings. There are two bolts on each clamp – simply lift the tab with a screwdriver to unlock the sleeve and pull back. The reusable couplers will transfer over to the Flowmaster exhaust, so take care of them.

We removed the four bolts that hold the tunnel support rail in, and were in awe over the size of the factory exhaust resonator – it’s freaking huge! I have never seen a resonator in an exhaust that big. We have no idea what is going on inside and whether it merges the exhaust together or if it keeps it separate. After we took the support bracket off, we noticed that the resonator was extremely narrow, which I am sure cannot be good for flow.

Moving towards the tailpipes, you will come to the first set of exhaust hangers right behind the rear end. There is a support rail that holds the exhaust together and the two hangers. Before removing the hangers, put a jack stand under each pipe towards the front of the exhaust to help support the exhaust while dropping it down, or have a friend hold it for you. These are slip on hangers, so a little lithium grease will aid in their removal. They should come easily since the car is new, but if not, you can gently pry them off with a flat head screwdriver.

There are two exhaust hooks on each behemoth muffler, and while it will take a little arm twisting to get to them, they come off rather easily. Lithium grease will also help get these hangers off. Support the exhaust when removing them, especially if you have the factory body kit like this Camaro has. The exhaust will then drop out in one piece.

The multi-piece design of the Flowmaster exhaust makes installation much faster. When installing the exhaust, only snug the clamps so you can correctly align everything first. The first part we installed was the Scavenger X-pipe that reattaches with the stock exhaust couplers to the down-pipes. Support the X-pipe during installation.

From there, the two mid-pipes are affixed to the back of the X-pipe with two supplied ring clamps. There are not any exhaust hangers on the mid-pipes. These pipes are directional, so make sure you have them pointing the correct way.

The last pieces are the most important – the 40 Series mufflers with polished tips. Carefully push the tips through the rear valance from the inside, then slide the mufflers and clamps onto the mid-pipes before connecting the exhaust hangers. Install the rearmost two hangers before installing the under differential hangers. Make sure that everything is properly aligned and finish tightening all of the clamps.

Our Impressions

We noticed a slight increase in sound when first firing up the Flowmaster-equipped Camaro, and slightly less of an increase at idle. The Camaro purred effortlessly, with a hint that something wasn’t stock about it. Free revving made the L99 come to life as the decibels increased dramatically.

Pull the Camaro out on the road and it’s a whole different story.

At first stab, the Camaro’s throttle response was noticeably faster. The Camaro was quicker to respond when we needed it to. Acceleration was crisper and there was a slight seat-of-the-pants difference in power. With the right foot down, the Camaro screams and overall is about 25% louder than stock all the way through the power band. With that louder sound at full acceleration comes the inherent drone at cruising, and while it wasn’t overwhelming, you should roll up the windows if you want to hold a quiet conversation.

Installed and Gone in an Hour

No doubt the Camaro comes with a suitable rumble from the factory – if you’re a grandma. Let’s be real, no one wants to hide the harmonious acoustics of either of the Camaro’s power plants. We were able to install the Flowmaster exhaust and get back on the road within an hour, and with greater than expected results. Not only does our Camaro sound better, it performs better as well!. Don’t forget to check out the video to really hear what the Camaro sounds like!

Article Sources

About the author

Mark Gearhart

In 1995 Mark started photographing drag races at his once local track, Bradenton Motorsports Park. He became hooked and shot virtually every series at the track until 2007 until he moved to California and began working as a writer for Power Automedia. He was the founding editor for its first online magazines, and transitioned into the role of editorial director role in 2014. Retiring from the company in 2016, Mark continues to expand his career as a car builder, automotive enthusiast, and freelance journalist to provide featured content and technical expertise.
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