The factors that allow a muffler to stop noise getting out the exhaust are also the
factors that create resistance to flow. So generally speaking, any muffler that makes
your car quiet will hurt power. Or putting it another way, performance mufflers (that
are usually of the straight thru design) will make your car LOUD
Abrupt changes in cross sectional area/gas velocity and sharp changes in direction
cause resistance to flow (back pressure) which hurts power. Building/tuning a decent
muffler for a stationary engine that runs at a constant rpm is easy, but doing the same
for a car engine that operates over a wide range of speeds is far more difficult. That
is one of the reasons the cheap holden mufflers I used (instead of the hugely expensive
OEM Toyota mufflers) sounded like crap.
I personally like this Magnaflow design which looks as so it should stop the fiberglass
absorbtion material from getting blown out in a hurry. But good luck with building a
better mouse trap
I can see what you were trying to do, and with a few hundred
hours of dyno time and dozens of prototypes, you may get it to work.
Cheers... jondee86