Exhaust Material Comparison
Aluminized, 409 or 304 Stainless Steel?
Many factory exhaust systems and components are manufactured using aluminized steel due to it being the most cost-efficient material in the automotive industry. It is easy to manufacture, costs less than stainless steel and gets the job done however, it is not as durable as stainless steel.
409 stainless steel was designed for the automotive industry to greatly improve the quality of factory exhaust components. No stainless steel is 100% rust-proof. All stainless steel will rust at various levels depending on its use and environment. 304 stainless steel has a greater resistance to rust than 409 stainless steel. Most visible rust is on the surface of the material and can be removed. Surface rust does not compromise the integrity of the exhaust component. Stainless steel is more durable in harsh conditions and is more resistant to snow, road salt and in regions near salt water.
| Material | Corrosion Resistance | Estimated Lifespan | Price | Magnetic? |
| Aluminized Steel | Good |  |
$$ | Yes |
| 409 Stainless Steel | Better (Surface Rust Only) |  |
$$$ | Yes |
| 304 Stainless Steel | Best (Discoloration From Heat) |  |
$$$$ | No |
Frequently Asked Questions
Should I choose aluminized or stainless steel?
Depends on where you are going to be driving and the conditions. If the exhaust is going to be exposed to road salt, snow or salt water, you want to choose stainless steel. Aluminized steel is hot dip coated with aluminized-silicon alloy to protect the surface however if scratched or dented the material can become compromised and rust.
409 VS. 304 Stainless Steel?
No stainless steel is 100% rust-proof. All stainless steel will rust at various levels depending on its use and environment. Although 409 stainless steel has the lowest chromium content of all stainless steels and may encounter localized (surface) rust. This can be removed. We use 409 stainless steel for a quality, cost-effective and durable exhaust component. We also use 304 stainless steel in many of our products. 304 contains more chromium and nickel for higher rust and corrosion resistance.
How do I clean surface rust off my stainless steel exhaust?
Early detection is key. As soon as surface rust is detected, allow the exhaust to cool first. You can use WD-40 and a Scotch-Brite pad or fine steel wool pad to remove the rust. You can also use a metal polish to clean the rust and help maintain the exhaust finish.
Which material last longer?
Aluminized steel is the most cost efficient exhaust material and can last for several years if exposed to moderate climate and not damaged. Aluminized tubing rusts from the inside out and may not be detected until there is a problem. 304 stainless steel may last longer than 409 stainless steel. However, either will most likely outlast your vehicle.
Why are some of aFe exhaust components offered in only 304 and some in 409 and both?
Cost and aesthetics. Both are great exhaust materials but 409 offers the best value and durability while 304 offers the best corrosion resistance and long-lasting good looks. Our engineers determine the materials by application, market and demographic. We are always looking at ways to improve our products.
