Materials used for exhaust manufacture

[kdamize]

I just wanted to know whether there is a specific material that is used for the construction of exhaust pipes like stainless steel. does the material has anything to do with the performance of the exhaust. thanks

[Setec Astronomy]

Performance in what regard? Most exhaust systems in recent years have been made from stainless steel to meet the EPA durability requirements. Usually 409 is used, which is a ferritic stainless which has fairly poor corrosion resistance as stainlesses go. I have heard of some mufflers being made from aluminized steel 3 or 4 years ago (I'm sure this was a cost saving measure). I have also heard of aftermarket exhausts being made from 304. This is a highly corrosion resistant stainless, one used for silverware, etc.

[kdamize]

i have made one with inox. i wanted to know if it would heat up too much or have any drawbacks.

[the other pc]

If you’re asking about engine performance then no, the material doesn’t really play into it.

Overall exhaust system design (4-into-1, tri-Y, etc) Tube diameter, runner length, bend radius, collector geometry, port/flange matching, baffle design (if any), thermal coatings and internal surface finish are significant factors.



Full race headers are usually made of mild steel, mostly because it’s easy to form into the desired shape, easy to weld and reasonably priced. Race cars don’t see that much actual run time so corrosion resistance and environmental exposure aren’t issues. (Turbo manifolds have extra considerations due to extreme temperatures.)


Inox exhausts should be great on a street car and very cool, although overkill, on a race car.


PC.

[kdamize]

till date i have made five. that material is quite handy and i know someone that can weld then. if i place two exhaust in a car does that affect the performance then. i wanted to know if it would be wise to have those on a 626

[the other pc]

I’m assuming from the pix that these are exhaust tips (and not some center muffler, resonator, baffle or whatever).

As long as the inside diameter of the tip is at least as big as the factory unit you shouldn’t see any adverse effect on performance. Having two won’t hurt either.

Unless the original tip was poorly designed and created a choke point, installing different tips/two tips isn’t going to improve performance noticeably.


PC.

[thump_rrr]

You can use either 304 or 409 stainless as was previously stated. 304 will keep its lustre unlike 409 which will turn brownish.
Some exhaust manufacturers claim that 409 is less prone to stress cracking than 304.
I had my 409 headers jet-hot coated with a titanium ceramic coating which also acts as a thermal barrier.