At Throughbred Diesel we strive to inform and help our customers as much as we can. This is a brief overview of Exhaust Systems materials differences pros, and cons.

304 Stainless Steel vs 409 Stainless Steel for Exhaust Systems


304 stainless steel and 409 stainless steel are both commonly used materials for exhaust systems, but they have some key differences in terms of composition and performance.


304 Stainless Steel: It is an austenitic stainless steel alloy containing 18% chromium and 8% nickel. This composition provides excellent corrosion resistance and high-temperature strength. It is also non-magnetic.

409 Stainless Steel: It is a ferritic stainless steel alloy containing 11% chromium. Compared to 304 stainless steel, it has less nickel and does not contain any significant amounts of nickel. It is magnetic and has slightly lower corrosion resistance.

Corrosion Resistance:

304 Stainless Steel: It offers superior corrosion resistance, making it well-suited for exhaust systems, especially in harsh environments or regions with high levels of moisture, road salt, or corrosive chemicals.

409 Stainless Steel: While it provides good corrosion resistance, it is generally not as resistant as 304 stainless steel. It may be more prone to surface rust or corrosion in aggressive conditions.

Heat Resistance:

304 Stainless Steel: It has excellent high-temperature resistance and can withstand the heat generated by exhaust systems without significant degradation. This makes it suitable for high-performance applications where exhaust gases reach extreme temperatures.

409 Stainless Steel: It has decent heat resistance, but it is not as heat resistant as 304 stainless steel. It may not be suitable for extremely high-temperature applications or high-performance setups.

Strength and Durability:

304 Stainless Steel: It is a stronger and more durable material compared to 409 stainless steel. It is less prone to deformation, cracking, or fracturing under stress or high loads.

409 Stainless Steel: It has good strength and durability for most standard exhaust systems. However, it may be more susceptible to deformation or fatigue failure under extreme conditions, such as racing or heavy towing applications.


409 Stainless Steel: It is generally more affordable than 304 stainless steel. It offers a balance of performance and cost-effectiveness, making it a popular choice for many OEM and aftermarket exhaust systems.

304 Stainless Steel: It is a higher-grade stainless steel, which makes it more expensive than 409 stainless steel. It is commonly used in premium or high-end exhaust systems.

In summary, 304 stainless steel exhausts offer superior corrosion resistance, higher heat resistance, and increased strength compared to 409 stainless steel exhausts. However, 409 stainless steel exhausts are more affordable and still provide good corrosion resistance and durability for most applications. The choice between the two depends on factors such as budget, desired performance, and environmental conditions.