I want to get a header back system with 2 3" pipes going to an X pipe and then into a dual 3" and then single 4" outlet. I can weld in the cutouts before I have it put in, but where do I get the system??
Ive called a few local places and no one has a mandrel bender and they all want $600 plus for the bent up crap.
I guess I could go with a 3" Y and weld the cutouts to that and into 3" pipe, but I dont think that it would flow well with out the cutouts open. This is going on a 402 with T trim and a small wet shot.

 

I don't know where you are located, but $600 seems kind of high to me. I had complete custom cat back done for $300 and it involved 2.5 tubing between the bed and frame in the wheel well with a 3" body lift. Needless to say a total pita.

 

You know how to weld? Order some mandrel bends off ebay and weld it up yourself if you do. If not, order them anyways and take it to your muffler shop and tell them how you want it done.

 

I had the same problem when I needed dual 3". Anyone that would have built the system that I wanted would have charged almost $1000 to do it. I wanted it to be flanged in a bunch of places for easy removal. I ended up taking that money to buy a MIG welder and all the stuff to go with it (Lincoln SP-135+) and did the entire project myself. I used Hooker mandrel bends and ring kits, Magnaflow mufflers and cats, Gibson tips, and Flowmaster tailpipe kits all from Summit Racing.

 

Ive got the same welder. How did you mock up the system to know where to put the bends and such?? I was thinking of getting more of the multi bends that I have for my intercooler setup here http://www.performance-curve.com/ind...ROD&ProdID=602 Think that would work?? I guess I need to go back to Home Depot and buy those clamps to hold everything together so that I dont have pipes misaligning as I weld them up.

 

mines not mandrel but I feel ya on the flanges
makes working on it easier

thanks for the ideas

 

I Was Thinking Of Doing That To With 2 3'' Pipes Going In To One 4" But When I Called To Get A Price On The 4" Pipe It Was 15.00 Per Foot

 

To build my system I started by welding the two mufflers together and welding on hardware to use the existing stock hangers.








At that point I cut the ends off my $1K set of TOG headers (that was an emotional experience) and welded on some reducers and flanges:


Sent the two collectors rearward with flanges and cats:


Started tacking everthing up in place as I fit it all into position:




Got to this point and then worked some more on the mufflers:


From there I bolted the two muffler flanges to the ones on the front sections and then connected the two pipes by making what goes between:


Welded those on to the removable muffler "module":


After that I used the Flowmaster tailpipe kits (x2)






All the welded-together pieces came out like this:




View of Gibson 3.5" slash tips after install:


Soon after installation I added a 2.5" balance pipe and then more recently I flanged the forward section 14" from the first flange to make the cats replaceable with "test pipes", only for "testing" of course, because I would never drive on the street illegally without catalytic converters...




All the MIG butt-welds are holding up nicely with their coatings of Rustoleum Cold Galvanizing Compoud. Of course there is no road salt here though:



So that's it.

The thing about 3" pipe is that it does NOT bend at all. There is no flex AT ALL. When you build your system you must keep this in mind as you fit your parts in there and tack them into place. The tollerance must be exact so that when hanging freely the system is not being under the stresses of being belt into place as it's bolted down. The easiest way to insure this is to completely bolt all the flanges together and then weld pipe in between. Like connect the dots. Once it's tacked, remove, and seal the piece up.

Using that practice worked great for me. I had never welded exhaust before, but that seemed liek the logical way to approach it. In fact, the welder when I started the exhaust was only 5 days old having been used two days before to make the crossmember seen in some of the pictures. That was the first thing I had EVER welded. MIG is super-easy. The investment in one of these units, especially a good one that will last, is something you will probably never regret.

 

All this for less than a 1000 bucks?

 

Hooker 3" collector ring pair kits $20 x4
Hooker 2.5" collector ring pair kit $20 x1
Flowmaster 2.5" - 3" reducer pair $22 x1
Flowmaster 3" tailpipe kit $68 x2
Hooker 3" Mandrel J-Bend $40 x2
Hooker 2.5" Mandrel J-Bend $27 x1
Magnaflow 3" in/out 5x11x22" $87 x2
Magnaflow 3" cats $97 x2
Gibson 3" to 3.5" SS slash tips $48 x2
Dynamax 3" Vortex cone inserts $70 x2
Miscelaneous Steel ~$20

That's about $989 in just parts.

The labor to do this job exactly like I wanted it would have doubled that.