<VV> Turbo Mufflers

[BobHelt@aol.com]

In a message dated 11/21/04 1:33:25 PM US Mountain Standard Time, 

Hi Everybody,
I respectfully and strongly disagee with what Flash says below, and with 
several other similar comments.

First, you are not trying to build pressure in the exhaust system. You want 
to build pressure in the intake system. The exhaust system should flow as 
freely as possible with as little back pressure as possible. You want to move the 
exhaust gases past the turbine, not bottle them up with restrictions. This 
means a low restriction free flowing muffler.

Next, although you may not know it, Chevrolet went to great lengths to have a 
new free-flowing, low back pressure muffler designed for the Corvair turbo 
engines. In fact the Corvair turbo muffler set a new record for achieving these 
goals. The Corvair turbo muffler was so successful in achieving high flows 
with low restriction that it became a mainstream item, and copied by all muffler 
manufacturers. Putting turbo mufflers on all cars became a national craze for 
a while back in the 1970s with several articles published in the popular car 
magazines comparing various turbo mufflers for ability to flow freely with 
minimum back pressure. 

Of course that was a few years ago, and certainly muffler technology has 
advanced so that even freer flowing mufflers might be available today. But that 
doesn't change the fact that the original Corvair turbo muffler was a milestone 
in low restriction and free flowing exhaust.

Regards,
Bob Helt


flash@vicspdi.com writes:

> Mufflers were restrictive on purpose ... imagine trying to build pressure 
> in a chamber ... the more flow out of the chamber, the harder to build 
> boost.  The mufflers were set to be the "correct" restriction given the 
> input (carb).  If you change to a less restrictive muffler and that is all 
> you do, you will certainly not have good boost.  If you also increase input 
> (such as Weber, etc) then you need a free flowing muffler ... but you are 
> in the experiment zone.