Couple of fab questions

[TooSlo5]

New to the site and found this section which has been very informative. Working on a couple of things for my TT project in my Chevelle and need some help. Did a search and didnt find what I was looking for so here goes. First thing is the exhaust outlet of my turbo's, BW S256's, are 3.5" and I am going into 3" down pipes. I cannot use a pre made cone due to all of them I found being too long. I also cannot find a smaller outlet pipe with the correct turbo side flange so my plan was to cone what I have. Any suggestions on how to go about doing this. My plan as suggested by Tim at Tim's Turbo's was to cut small triangles out of the pipe I have and bend in whats left and weld everything up. A little math will be involved but thats not a big deal. I didnt know if anyone had a "simple" way to accomplish this.
Second question is in regards to notching the wastgate pipes. I found a cool tool from pipe masters that you slip over the pipe and mark it for cutting but $50 bucks is kind of steep for somthing I may use one time and it only fits one size O.D. pipe.

Thanks!

[parsonsj]

An easier fix is to get some 3" tube and have a muffler shop expand it to 3.5"

jp

[TooSlo5]

Thought of that but didnt know how much it would stretch the metal. With these being downpipes and right off the turbo I didnt know if it would be a good idea or not. I am using 16ga mild steel for the downpipes.

[parsonsj]

If you use 16g ss you'll be fine, I'd think.

jp

[TooSlo5]

New to all this so I didnt know if 3" 16ga (mild steel not SS) would be thick enough after being expanded to 3.5". Kind of figured the thicker I could keep it the better due to the higher EGT.

Thanks!

[80proZ]

You can make a cone reducer with tube.
You need to quarter your tube first.In this case i would divide it into 6 equal spaces on the tube(the more cuts you make the rounder the smaller end will be).
Figure the circumference of each size(3" is about 9 7/16,3.5 is just shy of 11") and sutract the smaller from the larger,and divide that number by the number of cuts you plan to make.
Heck i'll post some pics to better show you tomorrow.I just made six reducers like this last week,going from 4.5 sch10 SS pipe,down to 3.5 inch.Its a little time consuming but it works great.

[80proZ]

First pic is a peice of 2.5,16 ga SS tube.I quartered it and marked my take out,which is 3/8" at each center line(circ. of 2.5 was 8 1/8",going to 2" which was 6 5/8".A difference of 1 1/2")
https://static1.pt-content.com/images/noimg.gif
Heres the cutouts
https://static1.pt-content.com/images/noimg.gif
Now i had to work it to get it to come in.I used a ratchet strap to help pull it together while working it with a hammer.A chain vice is the way to go for this.Also a deeper cut would also help,but you said a short reducer was needed,so i made my pie cuts 2".
https://static1.pt-content.com/images/noimg.gif
Welded and ready to clean up.
https://static1.pt-content.com/images/noimg.gif
I had a pic of it cleaned up,but i can't get it to load up.

[Mathius]

Never done this before, just theorizing in my head.... why not take your diameter, run the radius with a pair of dividers for your top and bottom, and then cut it out and roll it?

Mathius

[TooSlo5]

Looks easy enough, thanks!

[Twin_Turbo]

Now i had to work it to get it to come in.I used a ratchet strap to help pull it together while working it with a hammer.

I've used t bolt style hose clamps for this, really easy to work the pipe that way.

[jamheg1101]

I just use a cone die on the my shop press. 3" to 3.5" in less then 2" of tubing.