Header / Sidepipe Flanges

[Terry Stapley]

I currently have a slip fit exhaust and would like to remedy the slip fit with a header/sidepipe flange. My header pipes are 1.75" and sidepipe pipes are 2" to 2.125". Any suggestions or vendors would be greatly appreciated.
Can I expand the 1.75" header pipe ends to 2"?
Finish Line offers a flange but it is for 2" pipes!

[tfarhood]

Dynomax (Summit part # WLK-33231) makes one for a slip fit, but I think the smallest is 2.25". I have the same problem with my Backdraft pipes. They are slip fit and the OD of the pipes are only 2.00". If you find a smaller one, please post it here.

[blykins]

Hey guys....just make one.....Take a piece of 1/8 or 1/4 each steel.....get a hole saw to match the diameter of your pipes and cut it out. Make a flange to match the header.....and bolt them together with a thick piece of something in between for flex. You can slip your sidepipe or header into the flange and weld on the inside....then grind down flush.

[DC COBRA]

TERRY

Since you have a slip fit system to begin with, your headers should be at least 3/4 inch or more longer than you would need to use flanges anyway. So cut the end of the sidepipes off what ever you can spare, use the so called pieces (bushings) to slide over the header tubes to make a good fit in the flanges, that way you don't have to engineer something to work. If you can cut the pieces close to the thickness of the flange material you can hide the offsets with the weld bead. Just make sure you weld the insides up on the flanges for insurance, strength, and a good seal. Don't get carried away on cutting the sidepipes, to do a nice job the bushings don't need to be over 3/8 or less depending on the flange thickness.

DON

[Excaliber]

My friend likes my setup so well he's going to convert his sidepipes by welding a flange also. Makes it super easy to drop the side pipes at the race track. I have a set of "shortys" I bolt on when the sidepipes are off, looks really mean!

[Dwight]

I have changed the side pipes on my Blue E-M by welding a flange onto the headers. I made my flanges. My friend, Colin had a shop make him 4 flanges for his Shell Valley slip type headers. They made them out of 1/4" plate and charged him $7 each. We had to drill the 5/16" holes to bolt the flanges together but they cut the 2" holes. I welded the flanges onto his side pipes and headers. Job takes about 5 to 6 hours. A muffer shop can expand your pipes to 2".

DWIGHT

[Terry Stapley]

Thank you for the input. I think I now have a better understanding of how to approach this project. Being able to expand the header pipes to 2" will make less work. That way I can buy the flanges from Finish Line and grab the stinger!!

[sharpe 1]

I just finished doing just what you are talking about.Make sure you just tack the flanges to the pipes and fit them before you do the final welding .Mine moved a little on the drivers side and I had to heat them and jack it back up to the proper height. Was not much fun, but can be done. By the way, the flanges are easy to make. Good luck.

[MrMagoo]

Can you weld steel flanges to stainless steel tubes?

[mickmate]

Yes, if you use stainless wire and argon gas.

[MrMagoo]

Just plain Argon? I have Argon 98/ CO2 2 for stainless, I use plain Argon for back sheilding (such as inside pipes). I presume that will work?

[Esprit83]

You may get by using a common type 308 stainless welding wire, but the "book" on stainless steel welding calls for the use of type 309 or 310 wire. The higher chromium-nickel content in these wires overcomes the dilution in the weld caused by the carbon steel. Considering the vibration and heating/cooling cycles that headers are subjected to you should seriously consider following the proper welding procedures.

[cab]

use argon and if you have some 309 stainless steel wire use that works for steel to stainless welds

[Power Surge]

For the record, I have welded stainless to mild steel MANY times using my regular MIG steel wire and Stargon (Argon/CO2 mix). Never had one problem. And it's been mostly on exhaust related stuff (headers, turbo hot piping, etc).

[imagine2frolic]

Power Surge is correct....I do it daily, and never a problem

[mickmate]

A good rule of thumb with stainless welding is to go a grade higher with the filler wire than the parent metal. Weld 304 with 308 wire, 308 with 316, 316 with 321 and so on. It's easy enough to join the mild and stainless with TIG, Stick or MIG. I'd recommend using the higher grade of wire and a gas of mostly or all Argon. Your 98/2 will work great.

[Ant]

mickmate,

Exhaust system and general Welding, have just bought a Miller 150STH Tig welder!
I havent done much Tig work for a few years and then I was no expert, used to weld stainless steel tubed kite buggies for export! Since having the welder (2-3 weeks) have done a heap of practise, used most of a medium sized bottle of Argon. I am finding working on steel 1/8" and under with 1.6mm 6500 mild steel copper coated welding wire, providing I sand the metals first, the welds are turning out ok, but its easy to get a bit hot and undercut, hence I am finding "JUST" melt and keep dabbing the filler rod!!

This Tig Torch has a variable slide amperage control on the hand piece, which is quite good, I have just ordered the flexi head and Gas saver screen and shorter cup for tight spacers. Getting the welds tidy is another story but with my headers I have noticed it just melts through the inside using the above technique, but if I juice it then it leaves a bit to much of molten ring on the inside of the pipe!

[mickmate]

Ant that sounds like a great set up. You'll have more and more fun with that. Remember an Amp per thou (or 20 Amps per .5mm for you) will get you pretty close. The thumb control set ups I've seen but haven't used. One of me mates swears by his. Make sure you concentrate most of the heat towards the thicker metal like the flange rather than the tube with exhausts. I really enjoy TIG, with enough practice I'll get good at it one of these days. Cheers mate.