ideal collector design

[Sam_Q]

well that was a more direct answer than what I was expecting,

so whats it going on/is on?

[clubagreenie]

Ed's 1UZ, refer www.v-eight.com forums projects page

[JP]

for welding down in the center of the collector you can use a TIG with a lava nozzle, basically a very long gas shroud so you can get right into the collector and weld from the inside.

I made a set like your second design recently with the runners entering parallel, I welded around the outside as far as I could with the TIG and then used a gas lens with a fair bit of stick-out to weld up the inside of the collector.

Pic of the weld before cleaning it up with a die grinder:
http://users.tpg.com.au/adsl0uxv/collectorweld.jpg

[Sam_Q]

thanks JP, heres the problem I have and why my second collector there failed:

where the curved twin pipes join into one pipe it has a nasty step as you would expect, but I tried to correct it with my trusty die grinder. However it got so thin that when I went to weld it up more it burnt straight through. It has 2 x 1.5inch in and 1.75 out.

Now the only solution I am thinking of is:

chop the collector shorter, get a peice of 2 inch pipe, chop it lengthways, taper it, weld it up so one end is 1.75 inch then flatten the other end to suit the collector, hard to explain

[JP]

the ones I did were a 1.5" to 2" merge, I used a 90deg 1.5" mandrel, cut it down the middle to make two 45's, then tacked on about 15mm of straight to where they were cut.

I then placed this in the dropsaw in a small jig to hold the tube so I could cut parallel to the original leg on the end of the 90deg bend. I cut it about 3-5mm across from the inner face of the tube to allow enough room to get the tungsten in between the pipes when welding. Once both bits were chopped like that I faced them on a linisher and tacked them up.

Once they were tacked up I put a bit of scrap 2" tube in the vise and squashed it to an oval so it would fit onto the pointy 1.5" collector, once it was on there, I traced around the edge of it with a marker, removed the scrap tube and chopped the tip off the new collector with a 1mm cutoff wheel on the grinder. Then faced the end on the linisher and got the new bit of 2" tube in the vise again to squash it to the right profile to match the hole in the 1.5" tubes. I little more grinding, trimming and sanding and it had a perfect match which makes tigging it up very easy.

Some pics of the stages here:
http://users.tpg.com.au/adsl0uxv/collectorbuid1.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid2.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid3.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid4.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid5.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid6.jpg
http://users.tpg.com.au/adsl0uxv/collectorbuid7.jpg


Doing a 2">1.75 taper will work, makes it a lot easier if you have a linisher to square up the end after taking the slice out of the tube and welding it up.
Jason

[Sam_Q]

funny you show me this because I was thinking in the last 20 min of how I could do it like this, the difference being that I wouldnt tack weld a straight section on but I would weld on a curve that goes in the oppersite direction.

So it curves in and then curves back to make like an S shape, I will work at it

thanks for taking the time to explain this, it helps and I appreciate it

[Sam_Q]

also I have to ask, theres some peculiar dimentions on those pipes, why are the secondaies that length?

[JP]

space constraints, basically a practise test fit so a jig could be made a then a proper set fabbed

[Sam_Q]

wow if thats your practise set I would like to see the finsihed set, got any links for more info on this project?

[JP]

not yet, I'll be posting up a thread on this car when it's finished which should be in a week or two

[Sam_Q]

please keep me posted