I know the collector thing has been done 1000 times over here and it's like beating a dead horse, but i'm just looking for some tips from others who have built this specific collector. I don't want jig designs, angles other anything of that sort, i've already cut 100 pieces of pvc/abs trying to find the best combination.
What i'm having trouble with is the actual division in the flange. How do you guys go about this? Do you weld around the outside up to the middle divider and then weld the middle point from the inside? The piece of metal that divides the two sides is so thin it seems impossible to weld both halves of the collector to the outside.
Does anyone have any tips they can possibly share for the proper way to do the division and the joining of the two halves? I'm assuming welding from the inside is the only logical way.
Also, where the pair of pipes meet at the flange, is it better to cut them on an angle so that all 4 pipes end up pointing out like a traditional 4-1 collector or has anyone been successful just cutting the pair flat so that both pairs are parallel to each other and more up and down rather than pointing out.
I realize i probably won't get much feedback but for anyone who does feel like sharing, thanks in advance.

Edit - Even a few pictures would be more than helpful.

 

i welded mine in the past like the following: Weld all you can around the outside and then on the inner/middle area where they meet, i welding the INSIDE of the joint. I did about a .75inch overlap from outer/inner weld if you get my drift. So about 75% of the flange weld was on the outer area you can see and the last ~25% was done on the inner side of the flange area. HTH.

never had any problems with cracking, etc..

here is the only pic i have of one i did, you can barely make out where i welded the collector on the inside.

I welded more than I needed to around the seam on the inside, but a little overkill/piece of mind never killed anyone Hence why I so far havn't had one single failure with a manifold.

 

well i finished cutting up the collector and want to start welding it but had a couple questions first.

how long do most people leave the individual pieces? i cut my pipe 6inches and cut the collector from those, it seems a bit long when i test fit everything, but i am afraid i won't be able to weld pieces onto them if i go shorter since there will be less room to get inbetween.

also, when welding the collector to my t4 flange should i bolt a plate to it? a friend told me ince the flange i am welding to is threaded i will have a hell of a time getting the bolts out after it is welded. he said to weld it without and then to run a tap through the holes, he's a pretty smart guy but i don't know about this. fasten the turbine housing to it or not?

thanks

 

Well, with a 1/2" flange you can get away with welding without bolting it to anything, and it won't generally warp. I personally bolt it to a housing anyway though. I just use some anti seize on the bolts and never have a problem.

I've run into welding O2 bungs and have the O2 get stuck, but using anti seize solved the issue.

Collector wise, 6" is definitely long, especially for the divided. Anywhere from 3-5 inches is used...just depends on what you want. I just did a setup using 4", because that's what my collector jig is set up for.

 

thanks for the anti sieze idea, i'll give that a whirl.

and i just took a look at the collector, looks like i can get away with 5inches or even 4.5, guess i'll chop it down, it will probably make it easier to pipe the rest of the manifold that way.

 

well i just finished welding up my collector, it is far from being good but it will work for me.

i just had one question though, i have welded stainless plenty of times and everytime it always has gorgeous colour, my collector however is kind of dull. the stainless was cleaned very well with wire wheels and also cleaned with acetone, it however was the first time i ever used a gas lens while welding stainless, could this have been a problem.
also the haz was nice and even and very tight to the weld, would this be a good indication that i wasn't overheating because overheating was my original thought.

i had gas flow a little higher than i would normally have it at but figured since my backpurge line is teed off after the regulator i'd turn it up so that the torch would still have good gas flow, it was at about 25.