SS, 304 or 321

[vcarriere]

Because money doesn't grows on three, would it be good to build a downpipe from 321 SS, because of its resistance to heat and make the cat-back from 304 SS as its not as hot as the downpipe and because its cheaper. For a 3" diameter of 1' long straight pipe, there is a difference of 26$ (321 = about 37$ abd 304 = about 11$)

Thanks

 

[2-0turbo]

Originally posted by vcarriere
Because money doesn't grows on three, would it be good to build a downpipe from 321 SS, because of its resistance to heat and make the cat-back from 304 SS as its not as hot as the downpipe and because its cheaper. For a 3" diameter of 1' long straight pipe, there is a difference of 26$ (321 = about 37$ abd 304 = about 11$)

Thanks

If you were buying materials for a manifold, I would say 321. Otherwise, I think you are wasting your money. 304 is great stuff for exhaust material. You only really start to see it limitations on stuff like turbo headers, rotary apps or tightly enclosed setups (indy cars) where the temps get up really high. You need to use different filler metal on 321 (use 347 filler) which is not as common as the 308 filler used for 304 stainless. You are not going to be taxing you DP that much. Keep in mind, your turbo is going to suck nearly 300*F out of your exhaust stream. So even running 1600F EGT's, you DP will only see around 1300 and it only gets cooler as you go back.

Use 304. It is leaps beyond carbon steel or aluminized.