I am getting ready to put in a cat back system myself. I bought a nice dynomax 3" super turbo muffler.

Is this possible to do? I will have a mapp blow torch and a mapp and oxygen bernzomatic torch ( the kind you can buy that runs off of 1 liter size cylinders that you can buy for about $49 from home depot). I'll also have a cutoff tool and the other normal hand tools.

I would like to unbolt the stock muffler, and bend the 3" exhaust tubing with my brother over a round log by heating it with the torch and pressing on it until it assumes the shape of the old pipe (which has about 4 bends). Will this work with the small torch?

My cat is a 2 1/2" exit, which narrows down to a 2 1/4" exit in the last inch or so to meet the ford stock exhaust 2/14" pipe that goes to the stock muffler. Could I widen this up by heating it with a torch and using one of those exhaust widening tools from sears that uses a wrench to widen it?

Or should I take it to meineke and let them do the whole job?

Thanks,

Matt

1994 f-150 302 w/3.08 gears, 2wd.

 

First off, it can be done. I have done and will be doing a custom exhaust here soon.

BUT, wherever there is a bend, I highly recommend getting mandrel bent elbows. If you roll it around a log, the pipe will squish and cause a restriction. It's well worth the money.

As far as MAPP torches, etc, I don't know. I have always had access to ARC and MIG welders when I did them.

You can get the adapter from a parts house to go from 2 1/2 to 3" or 2 1/4" to 3". They're pretty common.

You can either weld the elbows in or you can use muffler clamps. I recommend using muffler clamps because then you don't have to be exact and there is alittle play in the system.

When you are putting it together, if you put alittle axle grease on the bolt and then tighten the nut, it will help keep moisture out of the threads and thus rust.

If you can eliminate any of the elbows, you will increase performance. An elbow is like 10' of pipe. With 4 elbows and the remainder of the system, I would say that you have like 48' of pipe to push the exhaust through. Excessive back pressure equals loss in economy and power.

 

Great!!! I will look into some mandrel bends... I might rent a wire-feed welder from home depot for the day to take care of the hangers and things. Thanks for the help.

 

I know it sounds like a good idea, but I think for the amount of trouble and screwing around involved, not to mention the stuff you'll have to buy do this, I think your money would be better spent having it profesionally done. It's just my opinion though


However, if you have your heart set on doing it this way, you could trying filling the part you want to bend with sand, which will change shape endlessly but will have the same volume. If you have figure out a way to keep the sand in place you're in business!

 

In order to keep the sand in place, you would have to weld caps on both ends, and yes, that does work to keep the pipe from collapsing.

I built a custom push bar for my old truck. I used heavy wall 2" fence pipe. I think I got to about 20* before it started to collapse. This was using a professional hydraulic tubing bender. Exhaust pipe is nowhere near as thick as heavy wall fence pipe.

You can end up laying out alot of cash if you don't have free access to tools. I work in a manufacturing facility and have weekend access to MIGs, stick welders, torches, plasmas, tubing benders, etc. My outlay would be parts and my time.

Renting a welder for a day will probably cost you $100. Atleast around here.

'Truckin is right, it can be alot of work. I guess you need to figure out what your time is worth. If you get a estimate from a shop, and then get a figure for the parts and what equipment you will need, the difference it what you would make for a lack of better terms. Say it's $100 difference. If it takes you 6 hours to do all this, you paid yourself $16/hr. See where I'm getting. If I can't pay myself to do it more than I make at work, I pay someone to do it. That's my rule.

Good luck.

 

You're right... after a point, the labor outweighs the savings. This might come quick on exhaust work which uses alot of specialty tools. Around here wirefeed welders are $39 from home depot, but a torch runs $120. I will take the truck to a few exhaust places and get some estimates.
Matt

 

Matt,

What part of MD are you in? How bad is the panic? I'm on my way tomorrow to Frederick via BWI for a week.

I love it back there. Used to spend alot of time in Cheverly in PG County, that's where dad grew up and now he lives up in Frederick, via New Mexico, Gaithersburg, and somewhere else down by Gaithersburg.

If you are in the DC area, have you ever been to Philadelphia Mike's in Bethesda? They have killer cheesesteak sandwiches.

Anyway, good luck with the exhaust system. I love to play, that's why I will do mine. It's a headache, believe me. The first one is always the female woof, if you get my point.

Keep us posted.

Joe

 

Yep, I see were you guys are coming from about doing it yourself. But as I get older I am starting to realize some things are better left to professionals who will do it right the first time, even if I have to pay for it. Man, maturity sucks.........

 

good point there. Of course, if professionals actually fixed things right the first time, I probably would have never been inclined to start mods and repairs myself. I'm still researching, but I'll share what I find and let you know what I do.
Matt

 

Another option is to do it the way I did. I'm sure I'm taking a performance hit over mandrel bent 3", but I went from single 2" to dual 2 1/2" and still gained some power.

I bought two pieces of 2 1/2" pipe for about $10 each and some clamps. For the bends, I cut a wedge out of the pipe most of the way thru, folded it, and welded it with my wire feed welder. The sharpest angle I had was about 20 deg.. It's definately not as free-flowing as mandrel bent, but it works for me.

Check out the pix here.

The best part is that I did it myself how I wanted and when I wanted.

Kevin K.

 

Looks like a good job to me... I too would recommend leaving it to the pros. For me, exhaust work always takes about twice as long as I think and I always end up cussing 3x more than I predict.