This is not for an FC, but I figured you guys would have more information on this than the first-gen section. Did some searching but did not find the answers I was looking for.

For some quick background, I'm doing a low-boost blow-through carbed streetported 13B with a stock S5 turbo. I don't have much money to work with and I can't weld stainless steel, so doing the whole system in stainless is out of the question. My options are using 2.5" thickwall Racing Beat pipe or 16-gauge mild steel in 3". Either way the system will consist of a Racing Beat presilencer and an offset/centered Borla ProXS out back. Now, I'm kind of picky about my exhausts, and in the past I've not had very good experiences with using normal-thickness exhaust piping on a rotary. It always resonates and drones and sounds crappy. However, those experiences were all on NA motors with 2" piping and oftentimes porting.

So: can I get away with 16-gauge 3" mild steel exhaust piping on a turbo car, or is it going to give me headaches and sound retarded? Is my system just going to be too loud in 3" anyway? Opinions and sound clips are welcome.

 

muffler and presilencer choice has a lot to do with it. The Racing Beat 3" exhaust for both FD and FC are pretty mild. When you have a turbo it smooths out the exhaust a lot unless you have something really loud like a Corksport or N1.

 

Check around at the local scrap yards, they usually have stainless tubing at very low prices.

 

Yeah, but those are all stainless, aren't they? Will the turbo tame the exhaust enough to use mild steel?

YaNi: thanks for the tip. I'll check it out. It looks like it might be possible for the welder I have access to to weld stainless after all.

 

So has anyone actually done a mild steel turbo exhaust and want to comment on it?

 

Hello I have used mild steel for turbo xaust. I personally have not had any problems with it. I would highly suggest some type of ceramic coating,because if left raw it will rust soooooo rast & then it just turns to crapolla!!!!

 

Cool. I think I'll go ahead and try it. Rest assured, I'll use high-temp exhaust paint to keep it from rusting away so fast.

 

The problem isn't painting the outside, it's that the moisture inside will cause it to rust from the inside out. Coating it get's all over it.

 

welding SS is no harder than welding regular steel. Actually, it may even be a little easier since the weld puddle doesnt seem to expand quite as much so its more controlled. If possible, i'd use SS just so you dont have problems with it in a few years. Either way, wall thickness has more to do with the amount of noise than the material itself does.

 

I could get aluminized pipe instead. Or how about 409 stainless? It's not so expensive, but from what I've read it's no harder than mild steel and is more difficult to weld. Could be exaggerated, though.

 

Dont worry about it and just use the Mild steel.... Your exhaust isnt going to rot that fast.....Remember, Most cars dont come with SS exhaust... Plus considering mild steel is a fraction of the cost of Stainless, even if it did rot out, you could still build another one! lol

 

Most auto manufacturers have used 409, aluminized 409 or 439 stainless for years.