Bolting on a performance exhaust system adds an exciting new tone to your car. But, that sweet song becomes annoying noise as corrosion eats away at your exhaust. If you want the music to last, start with steel that’s designed to outlive your car. Water, salt, and magnesium chloride (used to melt snow) are the natural enemy of an unprotected exhaust system. Thankfully, in recent years manufacturers have better access to a variety of stainless steels designed to prevent premature failure from rust, like T304 and T409 Stainless.
What Does Stainless Actually Mean?
Stainless refers to the metals ability to withstand rust and physical staining due to oxidization. While all stainless steels are superior from a corrosion resistance standpoint when compared to mild steel, they are not all the same. The two most common types of stainless steel used in the automotive industry are 300 series and 400 series. T304 and T409 being the most common variants.
What’s Better, T409 or T304 Stainless Steel Exhaust Components?
It depends on where you live and what the part is being used for. When it comes to parts where appearance is important such as exterior accessories like grille guards, nerf bars and dress up trim like grilles and exhaust tips, 304 stainless is what you’ll most commonly find. 304 stainless steel has the most resistance to rust and when polished it becomes shiny like chrome. It is also the best choice for use in the harshest conditions. Any rust spots that develop can be far more easily polished away.
Making the Right Exhaust Choice
So why not choose 304 stainless for everything? One of the drawbacks is that it’s more expensive and may be overkill. In areas where some discoloration or light surface rust is acceptable 409 stainless is less expensive and easier to manufacturer. Though surface rust will appear on 409 stainless it holds up significantly longer than mild steel. For vehicles that don't see salted roads or severe winters, 409 can be perfectly acceptable and save a few bucks to achieve equal levels of performance. Typically you see this material used in products under the vehicle like exhaust systems. Some exhaust manufacturers offer all 3 types of steel to give you multiple price points to choose from. So next time you see something labeled stainless steel, you might think twice and ask yourself just what type and what your intended use may be. The easiest way to tell which type a part is made from is by testing with a magnet: 409 stainless is magnetic and a magnet will stick to it while 304 is non magnetic. If you are unsure of what an item is made from and need more information, chat with us or give us a call and we’ll be glad to help.