What’s the Best Metal for Your Exhaust System?

Choosing the perfect exhaust pipe material for your car or truck depends on four defining factors: lifespan, price, corrosion resistance, and finish. This guide will compare some of the most popular metals used in car exhausts so you don’t end up with buyer’s remorse.

What Are Exhaust Pipes Made Of?

Exhaust pipes are made of a variety of materials. Some of the most common materials include aluminized steel, 409 stainless steel, 439 stainless steel, and 304 stainless steel. While these aren't the only materials exhaust pipes are made of, they're definitely the most common. Each of these different types of metals have their own pros and cons, so it's important to consider them all before choosing one for your ride.

Aluminized Steel Exhausts

Aluminized steel exhaust pipes use mild steel (almost 100% iron and 0.1% carbon) with an aluminum-silicon alloy coating. This coating provides decent protection against corrosion and rust. Aluminized steel pipes are easy to bend, so if you’re building a custom exhaust, this material might work better for you. While the finish is dull, aluminized steel pipes won't break the bank and can last up to five years.

• Lifespan: 3-5 Years
• Cost: $
• Corrosion Resistance: Decent
• Finish: Dull

409 Stainless Steel Exhausts

Most factory exhaust systems are made of 409 stainless steel. That’s because they can last up to ten years with only light surface rust or rot, which is removable with a wire brush. While there is a 10.5%-11.75% chromium content, the 409 grade does not hold a polish and won’t provide a shiny aesthetic. However, you could always swap out your exhaust tips for a more impressive material.

• Lifespan: 8-10 Years
• Cost: $$
• Corrosion Resistance: Good
• Finish: Dull

Pro Tip: In general, stainless steel is harder to bend and weld than aluminized or mild steel. It’s also more likely to crack due to the stresses of bending and welding. In some cases, you might need to treat stainless steel exhaust pipes with heat prior to bending to prevent cracking.

439 Stainless Steel Exhausts

The 439 stainless steel exhaust systems sit between the 409 and 304 options in quality and finish. An added 18% chromium content can resist rust and hold a polish. The only real difference between the 439 and 304 grades is the nickel content. While 304 contains around 10% nickel, 439 stainless steel holds only 0.5% nickel, resulting in less rust and corrosion resistance.

• Lifespan: 10+ Years
• Cost: $$$
• Corrosion Resistance: Great
• Finish: Polished

304 Stainless Steel Exhausts

304 stainless steel exhausts are one of the best widely available options. Built to last 10-20 years, they can withstand punishment from rain, snow, and road salt with ease. 304’s durability is a result of its 10% nickel content and 20% chromium content. These metals provide resistance to corrosion and high temperatures. The 20% chromium also gives this steel its shiny appearance. 304 is also known to turn golden-brown over time due to heat discoloration.

• Lifespan: 10+ Years
• Cost: $$$
• Corrosion Resistance: Best
• Finish: Polished

How to Test if Your Exhaust Is 304 Stainless Steel

If you’re unsure whether your exhaust system material is 304 stainless steel, place a magnet on your exhaust. If the magnet falls off, you’re in the clear. If the magnet sticks, you most likely have either aluminized, 409, or 439 steel. Magnetism is a result of a high iron content. Since 304 steel has almost 20-30% less iron than the other options, the magnet will not stick.

Other Exhaust Material Options

In your search for the perfect exhaust system, you may run into materials like 316 stainless steel, titanium alloy, and Inconel. These metals all offer great performance, but are far less common or more expensive than the options above.

• 316 stainless steel is indistinguishable from 304 aside from a small amount of molybdenum. Molybdenum is naturally resistant to chloride (salt) corrosion. This makes 316 a good option if you live by the ocean or drive on frequently salted roads.

  

• Titanium alloy is lightweight, corrosion and heat-resistant, and looks great. But these benefits come with a high price tag. Since titanium exhausts are rare, they're often custom-built. Titanium is also a difficult metal to work with, so you might need a professional to install it.

  

• Inconel is a top-of-the-line material, using nickel alloy for the best lightweight heat-resistance of any exhaust option. This is the material of choice for Formula-1 cars and serious racers.

  

How Will Exhaust Material Impact Sound?

While some people swear that titanium produces the best exhaust tone, there is no consensus on how much impact material has on sound. If you want to tweak your factory exhaust note, new headers, a new muffler or resonator delete, or different mid-pipes are the way to go.

Which Exhaust Material Is Right for You?

Now that you’re informed, it’s time to decide which exhaust material is best for your ride:

• Aluminized steel is budget-friendly and features a 5-year lifespan.
• 409 stainless steel is perfect for enthusiasts with a larger budget looking for durability.
• 439 stainless steel is closer to the high-end on the price scale but offers ten years of life and a clean polished finish.
• 304 stainless steel offers well over ten years of life if you have cash to burn and a passion for polish.