18 vs 16 gauge 304 Stainless tubing for exhaust

Joel K

Supporter
Hi everyone,

I’m getting ready to order the tubing for my SLC exhaust setup and see there are generally two thickness tubing that are available. I used 16 gauge stainless for the cooling tubes as was able to do a decent job welding that thickness myself.

Wondering if there is any specific reason to go with 18 vs 16 gauge in the exhaust.

A few reasons I came up with are:
18 gauge is less expensive and lighter,
18 gauge being thinner may be more difficult to weld.
16 gauge is stronger and perhaps last longer

As always, I appreciate everyone’s feedback.

Thanks,

Joel
 
Last edited:
That makes more sense.

Still an interesting question.

16ga is stronger, but heavier, so it needs to be stronger. This is just my thought, but if the pipes are supported at the collector, the 18 is likely plenty strong for naturally aspirated. But, yes a little more challenging to weld.
 

Scott

Lifetime Supporter
Joel,

I think you made the right decision. I spoke with my fabricator and depending on application he recommends the following:

*304 Stainless Steel: 16 for street and 18 for race
*321 Stainless Steel: 18 for street and 20 for race

The trade off being that if you're racing you'll likely trade off long-term durability to save weight. 321 will cost 30-40% more than 304, but it allows you to go up a gauge for similar durability. Titanium is thinner and lighter and > 2x cost and Inconel is the really high-end stuff.

Whatever you do insure that the hangers have vibration isolators and that you use a flex joint or a bellow.
 

Joel K

Supporter
Joel,

I think you made the right decision. I spoke with my fabricator and depending on application he recommends the following:

*304 Stainless Steel: 16 for street and 18 for race
*321 Stainless Steel: 18 for street and 20 for race

The trade off being that if you're racing you'll likely trade off long-term durability to save weight. 321 will cost 30-40% more than 304, but it allows you to go up a gauge for similar durability. Titanium is thinner and lighter and > 2x cost and Inconel is the really high-end stuff.

Whatever you do insure that the hangers have vibration isolators and that you use a flex joint or a bellow.

Thanks Scott, btw love the exhaust you are fabricating.
 
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