The 409 exhaust parts I have used turn a nasty brown color after running for a while. A tip or something would probably be fine, but if it sees a lot of heat 409 won't look too good after some time.

 

So what will be the corrosive difference between 304 and 304L? Im very picky about stuff on my new truck I want everything perfect. I wasn't going to o the cutout for a while but I have to take the front pipe off anyway to install my downpipe that I've had for 6 months I might as well get all the exhaust **** done at once. Will the 304 get any surface rust? I live where it doesn't rain much no snow or salt.

 

You prob won't even be able to tell a difference. Other then the carbon content, a lower carbon steel is supposed to be easier to weld, I never noticed. Even though it is stainless it will still get to some extant a slight rust to it, after time, esp getting hot and cold, unless it is super high grade steel, which stock exhaust really isn't.

John

 

What size cutout?

 

the L should be more resistant to sorrosion by nature of the lower carbon content but yeah, maybe not too much difference in your situation.

 

Well my corsa turboback was 1300 I hope its quality

The cutout will be about 3 foot frm the turbo so I expect the exhaust temps to get up a 1000*s or so on my big tune since it will hit 1600 right off the manifold. The welding part isn't a problem my welder has been doing it for almost 40 years and makes some beautiful welds. I may get the front pipe ceramic coated once I get the cutout welded in just so everything is nice and uniform.

 

4" I need to get the cutout and the electric actuator I wish DMH mde a 4"

 

it'll all turn black as coal, so no worries

 

The corrosion resistance of 300 series SS comes from the higher nickel and chromium content vs. 400 series. It also has and lower amount of iron too. The carbon content of the two is roughly the same, with 304L being roughly half of 409 or 304. 409 does have titanium in it, but its cheaper than 300 series due to the lack of nickel. If you go the 409 route, just make sure he uses a 300 series rod. It's actually pretty easy to weld the two together. But yes, one will corrode a lot faster than the other.

Oh yeah, 304L will the be the strongest of the three. That's where the low carbon comes in.

 

I have a 4" DMH right next to me
Sorry about the shitty cell phone pic lol.


What the hell do you think is going on my 4" downpipe?

My cutout is stainless as well
Dave sells the Dynomax SS cutouts with his 4" valves.
http://store.summitracing.com/partde...5&autoview=sku

For color id recommend using this cutout, its a QuickTime, it will color nicely since its 304 and its polished.
Definitely go with the DMH valve though.
http://store.summitracing.com/partde...5&autoview=sku