Tfrasca
Active member
- Joined
- Apr 20, 2015
- Location
- Ben Lomond, CA
I usually purge a tube for 3-5 minutes at 15cfh or so, then turn the purge flow down to 5cfh, this saves quite a bit of gas. Those purge plugs you can buy are nice but I've built many headers with just aluminum foil to cap the ends. A large gas lens helps immensely as well, I use a 1" diameter cup and lens from an automation torch that I hacked together but the SPW or furick stuff is also very good.
Once you have your sweet spot for welding current just weld short sections and jump around to different joints on the tube. This will keep the interpass temps reasonable so you don't have to wait too long. You'll notice pretty quickly if things are getting too toasty. If I'm in a hurry I will purge several runners simultaneously so I can keep skipping around to different tubes while others cool down.
Agreed, those spiral wound tube things both look and are ****ty.
Unsupported bellows are finicky. They really shouldn't be flexed at all on installation to maximize life and should only be strained in one direction if possible. It looks like vibrant sells lined bellows and it's very important to make sure the liner is oriented correctly with regard to the gas flow direction. Overbraided bellows are usually more resilient to cracking since the braid effectively works as a travel limiter and a friction damper against the convolutions which makes the bellows less likely to fatigue crack.
I went from a normal 7 cup to a Furick 12 with a lens and that helped immensely with stainless. I actually filled a whole extra canister to use for the manifold purge, but it's at Noah's house. Maybe for the wastegate tubing, I'll see if I can pick it up and rig a purge setup.
I've been looking at the wastegate situation and to do it right, it's going to be really tricky. BY FAR the easiest/simplest thing would be to run the front wastegate over the collector, pick up the rear wastegate, then turn down right into the 4" section of the down pipe. That would only be about 8-10" post-turbine, so not ideal. But maybe the 4" down pipe will help offset the flow issues? I'll try the right way first, but I'm doubting my abilities.