Quick question about welding exhaust flanges

[markp]

Hello everyone, I currently have an Apexi N1 downpipe and want to bring it to a shop to modify so that I can bolt on a high flow cat with it. I want to turn it into something similar to the RRE downpipe combo with a short downpipe connecting to a cat.

My question is when I have them cut my off a section of my downpipe equal to the length of my high flow cat, can the original flange of the end of the dp be cut off too and welded onto the newly cut side or do I need to buy another 3 inch flange to be welded on? Sorry, I really have no idea about welding so if anyone could answer this I'd really appreciate it.

 

[hereitcomes]

weld flanges on each of the sides of the pipes that you want to cut, and youll be able to make a test pipe - which is a piece of metal that you can put in place of a cat, and swap it out with a cat. Make sure you measure the pice, and keep your flex section so the exhaust can move around. Good luck buddy.

 

[probegonedsm]

yes, just cut the flange off, grind it down flush, then weld it onto the new pipe.

 

[Bud92gsx]

Try to find t ig welder for welding that stuff. It will seal better than ## standered mig.

 

[jake7420]

i really wouldnt about finding a tig. someone that can mig weld will seal just fine.

 

[russgvrs]

Granted a Tig weld is cleaner and a mig weld looks like ass but you can also weld it easily with a torch and some stainless rod. I always tack my stainless work together with a torch then tig it off the car. If you weld with a mig it will rust at a more advanced pace than the rest. Unless of course you use stainless wire that is a couple hundred bucks a roll. I prefer to use silicon bronze when welding stainless.

 

[tkelly27]

Cutting off that flange and re-using it will be fine, as long as the flange is the same as the cat's. You could actually just cut out the section of pipe, leave the flange and have them butt weld the two peices of pipe together. My experience has been that it's easier to do a pipe butt weld than weld a thin wall pipe to a thick walled flange at a 90 degree joint like that.

TIG, MIG, if it's done right on that joint there's no benefit to the more difficult TIG process. Unless you want it to look super nice, but I've seen some great looking MIG welds.