Stock-Can-Muffler-Mod-Cut-Gut-Thing

[guido4512]

For anyone that cares or has any interest in heavily modifying the stock cans into shorty's that sound pretty sweet. Or anyone that wants alot better sound and looks that is not filthy rich (like me) - here is how I made my SHORTY CANS. Read over it a few times, cuz I am sure I left something out or placed important details at the end ..........

I got this Idea from this board a couple years ago but I can't remember the name. So here's to you *whoever you are.........

Originally I was going to fab some stubbies to replace the midpipes. But certainly there would have to be a map change, not to mention a possible loss of torque.
So I opted to further modify my stock cans which I already polished and built a custom baffle for. I wanted lighter cans (and kewler looking) on a $0 budget.

In the end.............

Sorry for dark pic.

[USN05LE]

Great job. Anyway you can post up a sound clip.

Don

[guido4512]

Start by removing yer cans. If you can't grind, weld, hammer, pry and cuss, your SOL.
I already had a baffle I made for the stock length can so that the ex. ran straight thru..... I'll cover this later.

I also polished my cans last year. (see can polishing)

[guido4512]

Next, remove the end cap by lightly grinding the welds that hold those three button head bolts in place. Remove only enough material to get the bolt out! A dremel tool works good for this......

[guido4512]

Next, remove the 3 *O-rings that are on the studs on the inlet side......... those studs connect to the internal "cannister" which houses all the stock baffling.
They will be pushed out the other end later.. don't mess up the threads.

O - rings....

[guido4512]

Get ready for the point of no return.

The end of the can (where it is factory crimped) must be ground away to allow removal of the GUTS.

You can see here that my straight thru baffle is welded to the end plate. You will need to fab up a baffle using exhaust tubing.(More on this later)

[guido4512]

After grinding the edge away (use an 80 grit sanding disc on an angle grinder) clean any burrs that would hang up the internals.

You will have to HAMMER / PUSH the internals out from the other end. I used a plastic tipped hammer to reduce any damage. I also used a wooden handle inserted into the end of the can and used a pile driver type motion to drive out the internals. One slid out pretty easy, the other was a PITA.

Once out here's what they look like.......

[guido4512]

Next cut your aluminum can.

I cut 8" off.

I used a sawzall and had the can marked around the circumference so I could come back and even up the cut with my sanding disc.

[guido4512]

Next you need to shorten the internals by the same amount. Measure carefully here. If you remove too much you will be SOL again.

First remove the welds on the stud (intake) side of the internals.

[guido4512]

My measurements came to 8 5/8" from the end (outlet end) to the cut (where the stud cap will be welded back on)

Go ahead and cut it with the sawzall. Test fit with the end cap on and place the housing in the can. You should have about 5/8" overhang at the outlet end. (scroll down - more on this later.)

[guido4512]

I suggest removing all the internal baffling/tubes from the housing and fabricating a baffle out of some exhaust tubing.

I used 1 3/4" tubing and cut lateral slots the length of the tube in four rows. Don't cut too deep. Then, take a punch and bend the edges down to create the "baffles".
I also drilled some holes (probably not needed)

Looks like this when your done..................

EDit _ I guess you could use straight pipe here if you wanted a LOUDER tone. I wanted to introduce a 'lil more "backpressure" to keep my torque where it is.

[guido4512]

Weld the baffle into the end plate of the housing.
I don't have pics of this cuz mine were already done.Reference pic #5 to see placement. Also there is an angle cut on the end to match the angle of the stainless end cap. Wait until later to do this cuz you could index it wrong.

Just open the endplate of the housing enough to stick the baffle thru and weld it square. Leave 1 1/2 " out the end. Again, you will angle cut it later.

For length of the baffle you have to get your own measurements. You will want an inch or more sticking out the inlet side to mate with the mid pipe. I had to flare the end slightly, to mate with the mid pipe.

Also after checking the length 3x - it's time to weld the inlet cap (stud cap) back on the housing.

Notice the baffle tube sticking out ....

[guido4512]

After its welded up. Wrap the shortened housing with the dampening material that was cut to length.

It looks like this.

And its ready to stuff back in..............

Notice the baffle tube sticking out - this will mate to the mid pipe once its bolted back. Notice the flare? It must match that "internal" pipe in the mid pipe. Look in there -you'll see what I'm talking about.

[guido4512]

Now for the delicate part.
Stuff the housing back in the can. Be careful not to hang the material. It will jam if it hangs.

If you measured carefully you should have about 5/8 " overhang that we will "crimp" back to factory specs!

thus.....

[guido4512]

For crimping I used a PLASTIC tipped hammer. That aluminum is SUPER soft and will bend very easily.

Just start by bending the sides over by giving it a little tappy around the circumference.

Like so....

Edit:
oh -I did it out in the yard- cuz the grass is softer than my junked up workbench !!

[guido4512]

Keep working it until the edges are pretty much bent over........

[guido4512]

Next you will need to make a "punch" to finish the crimp.
I used a flat bar of aluminum stock with a radius ground on the end to match the internal curve of the can.

You need to punch the edges until it is smooth all the way around. Go around evenly working on all the high spots. That soft aluminum is easy to work out.


Keep working it - I didn't think this part would turn out too well, but it smoothed out nicely. The trick is the curved edge of my "punch".

[guido4512]

If you do get any burrs or small wrinkles, just file them off with your Dremel.

Now put the end cap back on.............


And replace the O- rings on the studs.

Bolt it on...

[guido4512]

Now, do the other one cuz the first was the "hard" one.

And now you have lightened SHORTY stock cans...

Let the begin..............

[Vic_E55_2001]

Awesome job and walk trough !