Will Pypes Stainless Rust
 

I have a Pypes stainless 3" kit for my 67 GTO. This is the stainless that a magnet will stick to. This is a car that will be garage kept and not driven in the rain, at least I don't plan on it. I have been told this will turn to brown rust. Has anyone used this stuff and can confirm this for me. I will not use it if that's the case so any help would be appreciated.
Thank you.

I think its more of a heat discoloration than rust, but it should not flake, peal, or rot,

Nate

I got a PM from someone who said they turned brown with light scale and the lifetime warranty is good only if holes appear. It only really takes one bad review for me so now I'm not sure what to do. I need to see if his is a garage kept dry car.

I just spoke to a friend of mine with a Pypes system he has had in his 65 Chevelle for 5 or 6 years garage kept and no sign of rust. He isnt sure if its aluminized or stainless but no issue. His 70 Chevelle has had an aluminized exhaust for 30 yrs and no rust. I guess we will see, not sure if the member that pm'd me about his being rusty keeps it garaged and dry.

Pypes may be different unsure of their exact metal composition but in general over time it may occur . http://www.maperformance.com/blog/40...ow-difference/ http://www.maperformance.com/blog/40...ow-difference/

So what I've read here is the 304 is better but they seem to only mention the road salt being a major cause of rust on the 409. Is it just because of road salt?

I steel wheeled my entire 2-1/2" SS Pypes system before I installed it.
It shines a little better and seems to be holding up well.No noticeable rust.I have the Dynomax VT mufflers.

My Flowmaster exhaust system is aluminized. It's been on the car for approx 11 years and 20-25,000 miles. No rust. It looks very similar to the way it did right after it was installed. Even the welds look good. Like yours will, mine has lived a life away from rain and spends it's off time in the basement. I can't see a stainless system rusting, used like I suspect the one on your car will be used....no matter which type of stainless it was bent from.

I spoke with Pypes and he basically said its the same stainless you will have on a brand new car, and a scotch pad will keep it clean. He said the 304 will turn also from heat. I'm gonna just try it.

The Pypes system I bought was all stainless including the band clamps. I polished the system before it was installed. Ther car sat out side for the last 4 years and the system still looks great. No rust and did not discolor. :)

It seems like Chris P may have gotten a bad batch. Everyone I speak to has no issue at all. I appreciate all the input!

2 seasons on my Pypes system, at the header collector towards the xpipe the pipe is darker than when installed. This is normal. Rear of the xpipe there is no discoloration and no rust anywhere from the header collector back.

I don't really know the difference between an aluminized system or stainless system, but I've used sluminized systems for 30 years or longer. I always take a scotch brite pad and then wipe them down with solvent before I wax the entire system and I've never seen any rust!

Thanks for the input guys.

In order of quality/corrosion resistance from worst to best:
1) aluminized steel
2) 409 stainless
3) 304 stainless

Aluminized exhaust is basically standard cold rolled steel with some aluminum mixed in for corrosion resistance. Aluminized steel, like aluminum will rust (after quite a long exposure to salt/water), but will appear as a whitish color rather than the typical brown/red rust.
The two grades of stainless above (there are dozens of others that may be used) are essentially the same but the 300 series contains higher level of chromium which gives it a shinier appearance and more resistance to corrosion.
For example, Toyota uses 409 stainless exhaust tubing & Lexus their luxury brand uses 304 stainless tubing.

I was told you can't polish the 409 but I took two pieces to work and put them on the bench grinder wire wheel after I welded them onto the header collector flanges and they get pretty shiny. I just dropped off the headers to get them ceramic coated as well as the flanges on those two pieces as they are not stainless. After they are all together I will try to polish it up a bit. Is there any kind of wax i can use to keep them shiny?

Hope it was a stainless wheel. It won't stay shiny if it was carbon.

I just tried a small area but when I try to do the full system I will try to find stainless wire wheels.

The increased resistance to corrosion of 304 versus 409 is due to the 8-10% by weight nickel (409 has none) not just the increase in chromium.

I took a scotch pad to my 2.5 inch Pypes system yesterday. Just got under the car and went from the down pipe. Cam out last oking pretty good, then went over it with a couple of stainless steel polishing wipes and a rag. System been on the car 4 years and that first maintenance it's been given. I thunk if you do it once a 1 year fold on new should keep it looking good