the_supernerd

I am putting a new free flowing muffler on my truck and I want to upgrade the size of the pipe. I am thinking about building the pipe myself. How important is it to be mandrel bent? I am assuming that I can get the flange and pipes at a local muffler shop? I have the original stock cat back exhaust system off of my truck. Would it be better for me to take it and the new muffler to a muffler shop and have them make a copy of it with new pipes and muffler?

jimbo74

make sure you weld everything... clamps work marginally and normally cuase problems later.... i would just ha shop fab up a whole exhuast, shouldnt cost too much... you dont need mandrel bends, regular are fine, you dont have a super modified engine where you need all that little extra out of it

the_supernerd

I will weld it. My cousin has a mig welder, so I will probably use that. I do not know if my stick welder will go low enough. If I regular bend a 2" pipe, what will diameter be around the bend? Will it go down to 1.75" of will it be more like 1.95"?

ZeroYota

You can buy mandrel bent exhaust pipes if you're really concerned about maintaining overall ID. It's more time consuming as you cut and weld the pipes to fit your rig, but it's worth it in the long run.

the_supernerd

I have seen those elbows that can be welded. Will a local muffler shop stock those so I can go get them while I work?

waskillywabbit

iTrader: (-1)

Considering time vs. effort, I ordered a new LCE header and high flow cat and took all my stuff to a muffler shop and let them put it on and weld it all up. Not worth my time when they could do it in a few hours and it look super.

ZeroYota

Most exhaust shops stock super long exhaust pipes (10' to 15'). Because it is so time consuming, muffler shops probably wouldn't stock the mandrel bent pipes since it's easier for them to crush bend their pipes. Your best bet is the local auto-parts store or SummitRacing.

Some tips: Remove exhaust system from cat-back to determine the types of bends, lengths of pipes & hangers you need. Check your local stores for pricing and while you're at it, pickup some high temp spray paint or rust preventive paint to protect your custom exhaust. The protective spray is only if you choose to buy aluminized piping versus stainless (uber money).

Good luck!

Fink

I just got all my stuff and had the muffler shop do it for me...I can weld, but not as good as they can!

Fink

the_supernerd

Thanks for the advice. I will see what I need and what it will cost. Then I will call some shops to see what they will charge to do it. I will get that paint. Is there anything I can put in the pipe to keep it from rusting inside?

cunninglinguist

Someone told me they installed an exhaust without bending anything. He used straight pipe and an offset muffler. I looked underneath my 83 pickup and yeah, I think he's right. But you should weld the connections together.

4Crawler

iTrader: (3)

Mine is all home-made:

http://www.4crawler.com/4Runner.shtml#Engine

One piece welded to the back of the rear cat flange to point at the muffler, then a length of s/s flex from the muffler, over the frame and out to an exhaust tip. I'll probably weld up part of the forward portion before the cat (I've changed it so many times that the clamps have been handy).

the_supernerd

I am thinking about using the flex tubing between the cat and the muffler and then welding up tail pipe. I could probably just use clamps and then bend a new pipe to weld on if I am not satisfied with the flex tubing.

4Crawler

iTrader: (3)

I have a length of flex tubing between the header and cat that I'll be replacing with a welded-in flex adapter. From the cat back to the muffler, I just use the stock bend off the rear cat flange and originally had an adapter (1-3/4ID - 2"ID) clamped there to match up to the 2" straight pipe and muffler. I later had that adapter welded in place since it kept leaking:

the_supernerd

Thanks for the picture of your exhaust. That will give me some more ideas. Nice suspension flex by the way.

the_supernerd

I just thought of another question. When I put the pipe and muffler together, should I use an exhaust pipe expander so the pipe will fit over the muffler so I can use a 2" ID pipe instead of a 2" OD pipe?

yellowspeedracer

i built mine just using the prebent pipes from summit or jegs. i didn't use a pipe expander and it's not necessary but it would be a good idea.
i would recommend making the exhaust atleast 3 parts. you can get 3 or 4 bolt flanges that would just weld right on the pipe and bolt together.

the_supernerd

Thanks for all of the advice. When I get my muffler I will get started.