TG02Z71

iTrader: (2)

I'm going to be removing the cats hopefully by this weekend and need to know what type of steel is used in the stock Y pipe. It looks like its stainless but I really don't know if it is. The reason being to get a strong weld that will last you need to use a certain type of filler rod or wire to weld the two together.
This link from Burns Stainless tells you to use 309 filler rod when welding 304ss to mild steel and 308 rod when welding 304ss to 304ss.
I am getting sections of 304ss soon to replace the cats with.

http://www.burnsstainless.com/304tub...raight304.html

white1

iTrader: (5)

Just use a mig welder, shouldn't matter as much then.

mjgjr72

stainless

Start2Fabrication

cheap 400 series stainless. it will still rust.

just mig it with a steel or stainless wire. the quality of the welding is much more important in this situation than the wire choice.

and even more important is the transition from one tube to another. many shops will slip a smaller piece of tubing inside to strengthen the joint, but it kills flow. a good butt weld or a slip fit weld will perform much better.

TG02Z71

iTrader: (2)

I will be slipping the replacement section over the existing pipes so I should be better off than the slipping inside method.
Thanks for the feedback guys!

greentahoe

iTrader: (2)

How are you going about doing this?? Are you simply going to unbolt your stock Y pipe, cut them out and then bolt back up?? My Y pipe is welded to my headers. Im not sure what I would do to get them back on other than trying to weld on flanges on my back to the headers. How difficult do you think that would be. I dont want to spend a ton as this exhaust system is going in the trash shortly after the motor arrives.
Is the piping 2.5 or 2.75?? Would the flowtech cutouts weld right up?? Is it worth using argon gas and stainless mig wire? Im going to use it on my intercooler piping, but here it would seem like a waste.

TG02Z71

iTrader: (2)

The pipes O.D. is about 2.45" I guess call it 2.5" O.D.
I still have my stock exhaust manifolds and plan on keeping them for a while,my Y pipe is bolted to my exhaust manifolds.
You could cut your cats off weld flanges to them and your Y pipe, as well as the peice you intend on putting in there to replace them so you would be able to swap back to your cats if need be.
If you do replace them with a straight pipe make sure the I.D. of your new section is the same or a little bigger than the stocker so you don't create a flow problem with pipe mismatch.