Everybody knows what you’re talking about when you say a car has “that Flowmaster sound” – over the past 25 years or so, that exhaust note has become synonymous with fast, street-driven cars. But the thing is, there’s more than just one “Flowmaster sound,” and depending on what you drive, they’ll typically offer a range of different exhaust systems to line up with your particular purpose, budget, and of course, tastes in “music.” The 2010 Camaro SS is a perfect example; Flowmaster offers two different systems with very different characteristics. To help explain what’s what, we’ve put together a back-to-back comparison complete with video to help you decide what’s right for you.

To understand where we’re going, we have to know where we began, and in this case we’re starting with the stock GM exhaust system. Like all OEM hardware, it’s designed with certain criteria in mind: it has to meet sound level standards, it has to not rust and fall off (at least until the warranty ends), it has to be easy to produce, and most importantly it has to be built to a price target. What it actually sounds like behind the wheel and outside the car are considered, to be sure, but they’re not exactly at the top of the development engineers’ list.

The factory Camaro mufflers look a little bit like roasting pans.

The stock Camaro SS system isn’t unpleasant-sounding by most people’s standards, but there’s certainly room for improvement. Looking underneath the car, you’ll see that there’s a crossover with a pair of integrated resonators in the center section, two giant pressed-steel mufflers, and in an unusually nice touch, stainless steel construction. Upgrading to either of the Flowmaster systems gets you mandrel-bent 409S stainless tubing for strength and durability as well, though beyond that, they’re very different both from the factory setup and from each other.

The Hushpower axle-back system uses compact cylindrical mufflers capped by polished stainless tips.

Hushpower Axle-Back

For easy installation, the axle-back system is the way to go. As you might have guessed from the name, it replaces the factory plumbing from approximately the axle to the tailpipe. 3-inch Hushpower Pro Series “shortie” mufflers with 4-inch polished stainless steel tips provide what Flowmaster calls a “moderate” sound, which is a good way to describe it – with the factory crossover and resonators still in place, it’s a noticeable change from stock, but not something that’s likely to get you the wrong kind of attention from law enforcement or the homeowner’s association. Per Flowmaster, “This system has a very deep, bassy sound with a relatively mild interior sound level. This is the system I would personally recommend for most people looking for an axle-back. It has a great sound inside and out.”

• 3-inch diameter muffler core
• 4-inch polished stainless steel tips
• Easiest Flowmaster system to install
• Mild interior sound levels

Flowmaster offers separate axle- and cat-back kits for Camaros with and without factory ground effects.

The mufflers themselves are made from a durable, fully welded 18 gauge aluminized steel case, with 409 stainless internal construction and patented ‘laminar flow’ technology. The kit requires you to cut the stock exhaust tube mid pipes but the installation instructions clearly explain how to measure properly for this procedure. The Hushpower kit uses all six factory exhaust hanger points to keep the tips in position and properly centered in the bumper cutouts.

The American Thunder cat-back system from Flowmaster is designed to bolt directly in place of the stock exhaust using factory mounting points.

American Thunder Cat-Back

For those wanting a more aggressive sound who are willing to do a little more work to get it, there’s the Flowmaster American Thunder cat-back system. Once again, the name tells you what you need to know – it replaces the entire exhaust system from the stock head pipes back. The classic 40-series mufflers are a 2-chamber “suitcase” design that is the direct descendant of Ray Flugger’s original. According to Flowmaster, this system has “A higher, much smoother tone than the Hushpower. Interior resonance is really pretty mild.”

• Replaces stock system from downpipes-back
• 2-chamber Classic 40-Series mufflers
• Integrated crossover
• 3-inch mandrel-bent tubing
• Mild interior resonance

The classic 40-series Flowmaster muffler is a 2-chamber design for maximum flow while keeping the sound relatively civilized. Relatively…

The system replaces the stock midpipe with a dual 3-inch setup with an integrated crossover, and like the Hushpower axle-back, it’s designed to bolt up using the stock mounting points and the complete hardware provided in the kit. Because there’s no cutting of the stock exhaust involved, if you have easy access to the underside of the car (in other words, a lift) it actually takes just a few minutes longer to do the American Thunder system, compared to the axle-back.

A little careful adjustment before the clamps are tightened gets the tailpipes centered.

Apples and Oranges

So which system is right for you? Like we said in the beginning, it all comes down to taste – the Hushpower system is less aggressive but still transforms the way your Camaro sounds inside and out, while the American Thunder cat-back is unmistakably Flowmaster, from a city block away. Per Flowmaster, “For most people who aren’t going to be doing any other modifications, the axle-back is the way to go in terms of bang for the buck. The cat-back makes a little more power, but is really going to stand out and be the choice for the customer is going to be doing other mods like supercharging, nitrous, etc.”

Fortunately Flowmaster makes it easy to “try before you buy” with sound clips for many of their systems available on their website, and if you check out our comparison video (shown above) you can hear these two systems back-to-back for yourself. The truth is that thanks to Flowmaster’s quality materials and solid engineering, you can’t really go wrong with either choice.