Hans Conser wrote:

Corvettes have come with titanium mufflers from the factory for 
years now. You can find titanium universal mufflers on the internet,
 but beware most of the cool car crowd like it for the flame colors 
of the tips rather than the actual weight loss. Many use a Ti 
canister with SS internals, or SS with Ti tips.

Here is a weight chart that was interesting: http://www.sae.org/motorsports/technology/fsae_muffler.htm

Here is Csaba on the corvette's mufflers:

Tech Highlight: The Wonder Metal
It's 43 percent less dense than steel but just as strong. 
It's highly resistant to corrosion. It can be cast, machined, and 
stamped. So why aren't cars built of titanium?

The purchasing department will be happy to explain why the 
use of this unique metal is rare. Standard steel costs about
 35 cents a pound. The high-strength variety is maybe a buck a 
pound. And stainless steel is about half again as much. Titanium 
is in a different league altogether. The alloys used in jet engines 
cost roughly $15 to $25 per pound. Even a grade suitable for mufflers 
costs about $10 a pound.

Moreover, although titanium can be stamped like steel, the technique 
is more demanding, possibly involving the use of heat, but Arvin, the 
company that makes the Corvette muffler assemblies, won't reveal the 
details. Titanium must also be welded in a pure argon atmosphere lest 
oxygen work its way into the weld and weaken it.

As a result, titanium components are very dear. But when you pick
 up a titanium Corvette muffler, the payoff is clear. It weighs 13 
pounds - almost nine pounds less than a muffler made of stainless steel. 
And it looks trick, with the characteristic dark-gray color that will 
turn rainbows of purple, blue, and orange with heat and time. Timet, 
the supplier of the titanium used in the Corvette's mufflers, is hoping 
to supply titanium springs as well. Because of the material's strength and 
stiffness, titanium springs require less wire than steel ones, which combine 
with the lower density to weigh as much as 75 percent less than a steel spring.
 The reduced bulk can also reduce hood height or reduce intrusion in a rear
 suspension on a van or SUV.

With all these advantages, count on seeing the dull-gray sheen of 
titanium on more cars and trucks in the future. - CC

 
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