Comments, criticisms welcomed - still work-in-progress, in cahoots with the talented & thoughtful Kevin at Ed Hansen's muffler shop in Spring Valley, CA...
After endless searching, I couldn't find anyone who has tried this approach, i.e., stuffing wrapped mufflers in over the stock 993 headers & cat. Since I'm in CA, this is largely intended to keep DMV & CARB folks happy and not require some sort of finagling with exhaust components every couple of years... and not set fire to my car.
It all fits up under the stock bumper with room to spare; will add suitably hacked valance once exits are finalized, as definitely going to longer tailpipes running sideways across car (under or over cat/mufflers,
TBD), exiting at quarters. Bit sad about this though as IMO the dual center-outs with a valance installed would look cool, even a bit mysterious on a 3.2 Carrera body, but not at the expense of drive-me-&-others-mad noise.
Just adding simple 6" extensions - not too obvious, as in bottom pic - as long as I dared for road use - to the exhaust tips/stubs (as shown in pre- & test-install pics) considerably reduced excessive low-freq & drone-type noise at idle and certain load/throttle positions between 2-3krpm.
It's only a windows-down issue and surreptitious night testing with longer chunks of pipes & bends draped and suspended Heath Robinson style off the rear end ("Oh that... It's an heated bike rack, officer!") continues, to determine optimal length (so far, it seems to be simply that LONGER = BETTER). First thought was maybe tip proximity was primary cause, but the '95 993 cat/collector already mixes the flows like a crossover and quick tests trounced that idea. It will probably do no harm to have them separated though, it might change the shape of the sound footprint from omnidirectional to more fore & aft, and up.
No noticeable heat build-up noted in bumper area or rear of engine compartment, it seems the wrap does its job when overlapped to give 200% coverage (tape is 2" wide on mufflers, 1" on pipes).
Another option after seeing how livable this is (everyday driver) will be to swap out the Magnaflow (2.5" inlet/outlet, 5"x14" can) for Flowmaster HP-2 shorties or custom Spintechs, will all fit same way.
Sounds awesome though, for the moment, especially winding up through gears to max rpm at full chat. But just a bit too loud, once or twice a day during urban errands, like an Army chopper, sets off a triple chirp shock sensor alert... nothing like as loud as many of the H-Ds running around
Naked - pre-install:
Naked test install:
One side, dressed & made-up (goth black):
What it's like now (with 6" extensions added to tips):
