agalaczy

Looking to purchase cat-back exhaust for my 2007 5.9 CTD.Don't want to pay for S/S if aluminized will be o.k.Had a S/S BORLA on my last truck and it had surface rust all over it after 3 years. Must hold up to Vermont winter road salt and slush.Appreciate any advice thanks,Andy.

bighornram

SS will still rust but will hold up way better than aluminized. but depending on price difference yoiu can sometimes buy 2 aluminized kits for the same as 1 ss kit. I bit the bullet and got the stainless. Same problem as you - road salt. No one around here seems to know how to drive in the snow so the roads are usually white with salt long before they are white with snow. They use way to much of it.

PupleDiesel

The aluminized is a step up from bare steel, but the aluminum usually burns off after the diesel heat cycles.

There are two different SS options. 409 which is not pretty, but will keep the rust at-bay for a long time and 304 which has more chromium, therefore costs more, but looks better longer. I bought the 409 SS for $425, the 304 SS was going for $650+. If you're really concerned about the rust, go w/ 304, you shouldn't have any problem w/ rust. It's your choice.

I'm w/ bighornram about the salt in our area. I say, if you can't drive in the snow, etc., stay at home.

rustyshakelford

my 5" is aluminized and cost me $310...not to shabby either

brett

Raspy

I bought the 409 system and right away I was sorry. Should have gone with 304 even though it was more expensive. Three years later it is all brown but not about to rust through. Around here the aluminized would probably last a lifetime but we don't have the salt problem.

Just as a little side note: When I called the supplier to complain about the 409 and see what we could do, he told me to go under the truck and polish out the pitting!

John

Rednecktastic

Yeah you have to polish 409 because it rusts, you probably notice it is cheaper therefore the catch.

Unless you want shiney go with regular aluminized.

PupleDiesel

Polish the 409 if you want to ruin it. From a metalurgical point of view, the 409 surface develops a coating, some call it rust, some call it corrosion, this coating prevents further deteriorization of the base metal.

Aluminized is plain steel w/ aluminum coating/plating. Once the aluminum coating is gone, you'll have rust like factory pipes.

If you want shiney, go w/ the 304.

Rednecktastic

I don't know why you couldn't polish 409 stainless. That would be like saying taking the dullness out of silver will ruin it.

PupleDiesel

The surface (oxidation) that develops is part of the pipe itself. The oxidation actually protects the un-oxidized metal under it from oxidizing. When polished it removes the oxidation, which is part of the metal, then more base metal is sacrificed to begin the oxidation cycle again. You can polish the 409, but why? It will only oxidize again. If you're after shiney, buy the 304.

Ship builders use low grade SS, lower than 409. It rusts just like regular carbon steel, but has higher strength properties important to structural strength for ships.

Rednecktastic

I use to own a machine shop that worked primarily with alloy metals. I understand what you're saying but it is kinda like polishing the tarnish off silver.

A lot depends on where you live and the contaminants you come into contact with. If you don't have to polish it often it might be worth the savings if you don't mind polishing it.

I agree 304 is the best.