The properties of 321 stainless steel vs 304 as seen in exhausts

fengshui-fu · 01-07-2003, 06:15 PM

Stainless Steel - Grade 321:
http://www.azom.com/Details.asp?ArticleID=967

Stainless Steel - Grade 304:
http://www.azom.com/details.asp?Arti...Grade%2B304%2B

Good read and something to think about with the advent of all these 321 stainless steel exhaust components entering the market.

Enjoy.

chris

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gravel · 01-07-2003, 06:33 PM

so basically 321 is the better choice for the uppipe and the 304 should be okay for the turboback.

I believe Shiv was the first to use 321 in the uppipe - way to go Shiv.

tuca33 · 01-07-2003, 10:56 PM

What is the temperature inside a WRX uppipe?
Thanks
Tuca

jrexilius · 01-07-2003, 11:04 PM

I think =< 1600F so which is ~850C I think.. so, yeah, its within the specs for 321..

oh yeah.. i think I heard that exhaust temps are ~800F which is ~450C which is also below the 500C limit for 304..

good post fengshui-fu

xstar · 01-07-2003, 11:45 PM

so what's the metal in the stock uppipe?

tuca33 · 01-07-2003, 11:57 PM

Cast Iron,,But is much Heavier..
Tuca

fengshui-fu · 01-08-2003, 12:10 AM

My pleasure. Im considering either the perrin UP or the APS ones, both 321 SS. And even though it is overkill, ill probably get the perrin DP to compliment my UP and crnak pulley and IC hoses. ALL PERRIN!!

chris

xstar · 01-08-2003, 12:16 AM

so cast iron is as resistant to really high operating temperatures? anyone know how high?

I just want a baseline to compare the 321 and 304 metals.

thanks.

tuca33 · 01-08-2003, 12:27 AM

Hey,,i Have a scooby sport 304..
is that really bad???I am nervous..
Will it be much much better to jet coat it??
Do you think the 304 is enough?
Tuca

fengshui-fu · 01-08-2003, 12:36 AM

I wouldnt worry unless you are going for mad power and actually change out your headers. If you do a header swap, then you might want to consider the 321 SS.

chris

mlambert · 01-08-2003, 12:52 AM

it doesnt hurt that the perrin up/down pipes look nice either

nhluhr · 01-08-2003, 10:03 AM

Quote:

Originally posted by tuca33
Cast Iron,,But is much Heavier..
Tuca

i don't think so... i've seen many stock uppipes and they never struck me as being a cast piece but i'm doing another uppipe install today so i'll pay attention to that specifically...

sweetsuby · 01-08-2003, 10:50 AM

304 is fine for either uppipes or downpipes. Although the gasses reach 1550 degrees the pipe never actually gets that hot.

gravel · 01-08-2003, 11:58 AM

The issue is with the number of heating cycles and maintained corrosion resistance and resistance to mechanical fatigue.

jrexilius · 01-11-2003, 07:38 PM

tuca33: jet coating inside and out will be an improvement. I am planning on doing just that even though i will have a 321 steel up-pipe.

01-07-2003, 06:15 PM	#1
fengshui-fu Scooby Specialist Member#: 21847 Join Date: Jul 2002 Location: New Jersey Vehicle: 2002 WRX Sedan World Rally Blue STX#555	The properties of 321 stainless steel vs 304 as seen in exhausts Stainless Steel - Grade 321: http://www.azom.com/Details.asp?ArticleID=967 Stainless Steel - Grade 304: http://www.azom.com/details.asp?Arti...Grade%2B304%2B Good read and something to think about with the advent of all these 321 stainless steel exhaust components entering the market. Enjoy. chris * Registered users of the site do not see these ads.

01-07-2003, 06:33 PM	#2
gravel Scooby Newbie Member#: 11962 Join Date: Nov 2001 Chapter/Region: Tri-State Vehicle: 2002 WRX SILVER	321 is the better choice for the uppipe then so basically 321 is the better choice for the uppipe and the 304 should be okay for the turboback. I believe Shiv was the first to use 321 in the uppipe - way to go Shiv.

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01-07-2003, 10:56 PM	#3
tuca33 Scooby Newbie Member#: 24303 Join Date: Sep 2002 Vehicle: 2002 Impreza WRX Black	What is the temperature inside a WRX uppipe? Thanks Tuca

01-07-2003, 11:04 PM	#4
jrexilius Scooby Newbie Member#: 21713 Join Date: Jul 2002 Location: evanston, il Vehicle: 2002 wrx sedan black	I think =< 1600F so which is ~850C I think.. so, yeah, its within the specs for 321.. oh yeah.. i think I heard that exhaust temps are ~800F which is ~450C which is also below the 500C limit for 304.. good post fengshui-fu

01-07-2003, 11:45 PM	#5
xstar Scooby Specialist Member#: 10821 Join Date: Oct 2001 Chapter/Region: NESIC Vehicle: 2008 WRB STi	so what's the metal in the stock uppipe?

01-07-2003, 11:57 PM	#6
tuca33 Scooby Newbie Member#: 24303 Join Date: Sep 2002 Vehicle: 2002 Impreza WRX Black	Cast Iron,,But is much Heavier.. Tuca

01-08-2003, 12:10 AM	#7
fengshui-fu Scooby Specialist Member#: 21847 Join Date: Jul 2002 Location: New Jersey Vehicle: 2002 WRX Sedan World Rally Blue STX#555	My pleasure. Im considering either the perrin UP or the APS ones, both 321 SS. And even though it is overkill, ill probably get the perrin DP to compliment my UP and crnak pulley and IC hoses. ALL PERRIN!! chris

01-08-2003, 12:16 AM	#8
xstar Scooby Specialist Member#: 10821 Join Date: Oct 2001 Chapter/Region: NESIC Vehicle: 2008 WRB STi	so cast iron is as resistant to really high operating temperatures? anyone know how high? I just want a baseline to compare the 321 and 304 metals. thanks.

01-08-2003, 12:27 AM	#9
tuca33 Scooby Newbie Member#: 24303 Join Date: Sep 2002 Vehicle: 2002 Impreza WRX Black	Hey,,i Have a scooby sport 304.. is that really bad???I am nervous.. Will it be much much better to jet coat it?? Do you think the 304 is enough? Tuca

01-08-2003, 12:36 AM	#10
fengshui-fu Scooby Specialist Member#: 21847 Join Date: Jul 2002 Location: New Jersey Vehicle: 2002 WRX Sedan World Rally Blue STX#555	I wouldnt worry unless you are going for mad power and actually change out your headers. If you do a header swap, then you might want to consider the 321 SS. chris

01-08-2003, 12:52 AM	#11
mlambert Scooby Guru Member#: 13831 Join Date: Jan 2002 Location: 99 problems but a bitch aint 1	it doesnt hurt that the perrin up/down pipes look nice either

01-08-2003, 10:50 AM	#13
sweetsuby Scooby Specialist Member#: 14043 Join Date: Jan 2002 Chapter/Region: MWSOC Location: mi Vehicle: 2002 WRX, ForesterXT support urlocal racerGrL!	304 is fine for either uppipes or downpipes. Although the gasses reach 1550 degrees the pipe never actually gets that hot.

01-08-2003, 11:58 AM	#14
gravel Scooby Newbie Member#: 11962 Join Date: Nov 2001 Chapter/Region: Tri-State Vehicle: 2002 WRX SILVER	The issue is with the number of heating cycles and maintained corrosion resistance and resistance to mechanical fatigue.

01-11-2003, 07:38 PM	#15
jrexilius Scooby Newbie Member#: 21713 Join Date: Jul 2002 Location: evanston, il Vehicle: 2002 wrx sedan black	tuca33: jet coating inside and out will be an improvement. I am planning on doing just that even though i will have a 321 steel up-pipe.