Sound Testing: Flowmaster's 8 Most Popular Mufflers

[69hugger]

Can someone explain the difference between 304 & 409 stainless? Just for those of us who don't know....

THANKS!

[WSSix]

409 will corrode to an extent while 304 won't. A magnet will stick to 409 and not to 304 if you need help determining which stainless steel an exhaust is made of. Please understand this does not mean 409 is bad. It's still much better than aluminized steel. It's just that it is cheaper than 304 so the price should reflect that. My pypes system is 409.

[69hugger]

Thanks Trey.

[Ron@Flowmaster]

Originally Posted by 69hugger

Can someone explain the difference between 304 & 409 stainless? Just for those of us who don't know....

THANKS!

Originally Posted by WSSix

409 will corrode to an extent while 304 won't. A magnet will stick to 409 and not to 304 if you need help determining which stainless steel an exhaust is made of. Please understand this does not mean 409 is bad. It's still much better than aluminized steel. It's just that it is cheaper than 304 so the price should reflect that. My pypes system is 409.

Great description. 409 stainless steel has a slightly higher iron content than 304(shiny) stainless steel. This makes it easier to weld, more durable, stronger and longer lasting than a 304 stainless steel, but because of that, it will show light surface rust over time. This surface rust actually acts as a barrier to protect it from rusting completely through even under extreme conditions. Most major automakers recognize these benefits and currently use 409 stainless for their OEM factory exhaust systems. Because of its durability, we back our 409 stainless steel mufflers, systems, and kits with a Lifetime Limited Warranty, so you'll never have to buy another system again.