Aka 'turbo' (reflective) and 'glasspack' (ceramic fiber) in the States. I had
a mild steel Ansa which is a glasspack
design and I don't recall it ever sounding tinny, and the steel was in perfect
shape long after the fiberglass packing
was shot. I'm still using the pipes in my current, cobbled together system
(Frankenmuffler). The Ansa steel was quite
thick (16ga maybe), and the Falcon SS seemed thin to me--maybe it's a question
of steel thickness.
Kees, do you know for certain whether original Healey mufflers (forget the
brand name) were turbo/reflective type?
They're shaped like glasspacks.
Bob
On 2/14/2013 10:36 PM, Oudesluys wrote:
> There is a difference in working principal involved here. The original type
> mild steel exhaust dampers are usually of
> the reflective type, the exhaust gasses pass through a series of chambers of
> a predetermined size. These chambers are
> separated by barriers that are perforated or fitted with one or more tubes of
> varying diameter etc to enlarge the path
> the gasses have to go and to absorb certain frequencies. It is a fairly
> complicated matter. They can be rather
> restrictive.
> Stainless Steel systems are usually straight through systems with much less
> restriction. The noise absorption is
> effected by ceramic wool or stainless steel wool with which the damper is
> filled that fits over the perforated exhaust
> pipe. Initially this gives a rather harsh sound but after a while the ceramic
> or ss wool gets coated with soot and
> partially gets blown out which will dull the sound but increases the sound
> level.
> In general the reflective systems do a better job damping the noise but offer
> less performance.
> There are also systems that are a combination of the two.
> There are some stainless steel exhaust systems that are of the reflective
> type and made with the same gauge material.
> These sounds the same as the original mild steel exhausts.
> Sound is not a question of stainless or mild steel, it is a question of
> construction.
> As classic/vintage/antique not catalyst cars are only little used in general
> stainless steel is mostly used to prevent
> having to renew the exhaust system frequently because of rust from the inside
> out. The manufacturers design their ss
> systems with a certain sound in mind. Usually loud and dark.
> If mild steel is used in combination with ceramic or (stainless) steel wool
> this will often cause rapid serious
> corrosion as non catalyst exhaust gasses produce acids together with
> condensation, especially on short runs where the
> exhaust has not been fully warmed up. The wool will absorb the moisture.
>
> Kees Oudesluijs
> NL
>
>
--
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Bob Spidell San Jose, CA bspidell@comcast.net
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