Do I Need A Stainless or Aluminized Steel Exhaust System?

Almost every exhaust manufacturer offers stainless steel exhaust systems because:

• Stainless steel often looks better and can be polished (depending on the grade)
• Stainless steel is very resistant to corrosion, so it’s easier to warranty than aluminized steel

The question is, are these reasons good enough for you to buy a stainless steel exhaust?

Questions To Ask Before Buying A Stainless Steel Exhaust System

1. Do I need corrosion resistance? If you live in a state where copious amounts of salt are used to melt road ice during the winter months, you should probably buy stainless. An aluminized system can survive in harsh climates, but it’s a lot more likely to rust out after 2-3 years of normal use.

On the other hand, if you live in a dry climate and/or a place that doesn’t get a lot snow and ice (and therefore very little road salt), an aluminized system can last as long as 10 years. Next, you want to ask yourself…

2. Do I want to invest in a system that might outlive my car? If you’re buying an exhaust system for a car you plan to keep for a long time (10 years or longer), stainless is a smart choice. Even if you live in a dry climate, rust can eventually work against an aluminized exhaust system.

On the other hand, you may be buying a replacement muffler for an older vehicle that’s on the downside of it’s life. If you’re driving a car, truck, or SUV that has a lot of miles, you might be wise to minimize the amount of cash you put into it and opt for aluminized steel instead of longer-lasting stainless.

Note: Stainless Steel Systems Are NOT All The Same

There are two grades of stainless steel commonly used in exhaust systems:

1. 409 stainless. 409 has become the defacto material of choice for most new vehicle manufacturers, mostly because it offers an excellent compromise between strength, resistance to corrosion, and cost. A 409 stainless steel exhaust system should last at least 8 years in almost all climates and weather conditions, but it won’t last forever.

2. 304 stainless. 304 is sometimes referred to as “marine grade” stainless because it is very resistant to corrosion from salt water. As you can imagine, an exhaust system made from 304 stainless steel can last a very, very long time. Shuttleworth Exhaust Products, a North American exhaust manufacturer is offering a large variety of 304 stainless steel.

304 stainless is also nice because it can hold a polish – something that 409 stainless can’t do. Of course, no stainless steel exhaust system can maintain a polished look unless it’s very clean…which means most people will never notice the difference.

Stainless Steel Exhaust System Myths

“Stainless steel lasts forever.” Not true – all stainless steel will eventually rust out. However, 304 stainless won’t rust out for at least 20 years. 409 stainless, which contains less Chromium and is therefore less expensive, won’t rust out for at least 8 years.

“Stainless steel sounds different/better.” Not really…the sound difference between exhaust systems is almost exclusively the result of muffler design.

“Stainless steel is stronger.” Not necessarily. Stainless can be more brittle than aluminized steel, and it has been known to crack. While the best quality stainless steel is thick and strong and shouldn’t break under any normal conditions, not all exhaust manufacturers use the best quality stainless.

“Stainless steel won’t stain.” Wrong. Despite it’s name, stainless steel is NOT stain proof. 409 stainless, in particular, will often take on a reddish hue. 304 stainless steel can discolor under extreme heat, and may not always polish back to the original shine. 304 stainless can also become pitted.

Bottom Line: Stainless steel exhaust systems are often a smart choice, but there are plenty of good reasons to buy an aluminized exhaust instead. If you do opt for stainless, be sure to check if you’re buying 304 or 409 stainless