Exhaust build - getting the angle right...

[zeroaxe]

Hi people,

I would like to pick the custom exhaust builder's brains on here. I am in the process of doing my first ever 'build'. Not so much a build, but rather a 'face lift'. Thing is that I'm changing from a normal 'side muffler' to an under seat muffler. All is going well so far. I am now at the stage where I need to connect the muffler (with it's own down pipe (modified already) that goes down right to the swingarm) to the stock headers. A 50mm straight pipe of 50cm will do. However, I'm stuck with the elbow. A 90° bend it too 'closed', and a 60° bend is too 'open' :-\

To get a custom angle bent here in France, is near impossible to find a company to do that. And number 2, in my experience with anything non-standard/off the shelf, you have to shell out serious bucks. And I'm not prepared to do that, not for this build anyway.

So here is my dilema/question. Which of the two elbows are easier to modify and still get a smooth transition? My ideas are as follows:

1 A: For the 90° elbow. Either cut with a dremel (to keep the cuts about 1mm thick) on the inside of the elbow, maybe like 3 cuts and bend the elbow open and TIG weld it closed. (More filler rod/passes will be needed as the gaps get BIGGER by bending it open). Grind smooth, sand, polish. I think the grinding smooth might be a problem as it is on the inside radius.
1 B: Cut with Dremel on the outside of the elbow and bend the elbow open (this way, closing that gaps already BEFORE TIG welding) Grind smooth, sand, polish. This seems to be more logically easy to do, as it is on the outside radius, so reach will be easier.

2 A and B: As above, but obviously the overall angle would have to be 'closed'.

Any insight from those with experience would be greatly appreciated. If my explanations are not clear, please feel free to let me know, and I'll see if I can make a couple of quick sketches.

Thanks in advance,
Cheers!

 

[HerrDeacon]

If you pick up something like a mandrel bent UJ pipe you can basically make any angle you want. Something like this pipe is typically used for making custom pipes when you don't have access to a bender.

 

[alzcbz]

Use the 90. Cut it off at the angle you need and the weld on a straight to that.

 

[zeroaxe]

If you pick up something like a mandrel bent UJ pipe you can basically make any angle you want. Something like this pipe is typically used for making custom pipes when you don't have access to a bender.

Thank you for your reply. Wow! This piece is exactly what I need (or rather want!). Unfortunately the shop that I found online in France stocks a lot of different diameters of 1.5mm Stainless tubes, but only 45°, 60° and 90°. So I will have to make do without this C J bend (such a shame). But thank you so much for responding!

 

[zeroaxe]

Use the 90. Cut it off at the angle you need and the weld on a straight to that.

Thanks for the reply. Hmmm, k. I know what you mean. Makes sense! I assume that I should measure 'perfectly' to make a right angle cut so that I don't end up with an oval, right? Any way to make sure or measure correctly before I make the cut? Thanks in advance!

Cheers

 

[neevo]

Find a metal railing fabrication place, that's where I get my tube bent. They don't advertise headers but they make custom bent sections out of stainless. My headers are costing my $350 AUD vs $1000 at an exhaust place.

To mock them up I have done it in PVC pipe and a glue gun to cut and adjust the angles. These will be given to the pipe bender to replicate.

 

[Parkwood60]

I would cut a couple of small wedge shaped slices out of the 60* bend and make it 75* or whatever the angle you need it to be. You could do the same with the 90* too. Depends on what is closer to what you need. If you do it right, and you are good with a TIG welder and a cut off tool you will hardly be able to tell, especially if its under the frame/seat