exhaust project #1: "loopy"

i was in need of a project i could complete and put to work in a short amount of time. the slow pace of my F23 project can be pretty discouraging and oppressive at times, so i was ready for a pick-me-up accomplishment.

in sorting the garage and deciding what to sell to make some extra cash, i came across my original '96 DX civic muffler. it's been hanging on the wall in the garage for three years since i swapped it for a GSR unit to get the larger piping.

at first i was just going to cut it open and see what all was in there and how it was put together.

turns out it's little more than two baffle plates and three lengths of tubing with strategically place perforations of varying sizes..


not too great for flow, but great for an economical quiet ride.


once i saw that i got to thinking, "hey, i've got this other crappy sounding eBay fart can i'll never use for anything. let's see what's in it!" so i cut it open too and found a finely preserved length of perforated tubing.


well what would that look like in the OE case? so i gutted the OE case by cutting the inlet and outlet then removing the internals as a single unit.


then tried the perf. tubing..


obviously it'll need to be run at an angle from the inlet to outlet. but i just didn't like the poor use of space and lack of "something different". so i spent a few days brainstorming. here's my original design concept in 3D CAD

to get ^there^ i would need to divide my perf. tubing into thirds, remove the stock tubing and weld in some mandrel bends

stock tubing removed from baffles and divided perf. tubing


so how about those mandrel bends? oh and don't forget to get enough for the inlet and tail pipe sections.

notice the piece of perf. tubing wrapped in bronze wool. just like steel wool but bronze.. pretty simple concept. (and yes, that's a rubber ducky towel )
not bad to look at either, but it's all getting sealed up in the case so...


anyway, here's some mock up shots.

i used hot glue to hold this in place ...seeing as i sold my crap welder and i'll have to wait to use a friend's MIG when we can get our schedules to line up.

here's the empty case next to the new piping/internal structure


it still needs some good quality time with the Dremel and angle grinder to get the fit just right before welding.

oh, and what, you ask will fill the space between the bronze wool in the middle chamber? after much deliberation and waffling i went with ceramic fiber blanket from Axner.com. IIRC, what they sell goes by the trade name Superwool and is made by Thermal Ceramics. it's a close cousin to fiberglass but with much, much better thermal properties including a max op. temp of 2300º F! have a look at this video comparison of rock wool (the type of 'fiberglass' typically used in aftermarket mufflers) and ceramic fiber


pretty compelling.

so all that's left is trimming, welding and testing. it could be a month before i can get it welded up... i'll be on vacation and so will my buddy with the welder.