Michael:
The stock muffler is SO bad in terms flow that a guess would be
that anything over 3,000 is severely degraded in terms of power. You
will not notice any difference at low RPMs as the engine is not pumping
out much in the way of exhaust gasses.
My experience is limited to the DynoMax Super Turbo, which is a
three pass baffled style muffler with no fiberglass packing. On a Chevy
350, it was barely louder (from inside the car) than the stock muffler.
Vizard claims that the cyclone sonic Turbo will meet European noise
standards in his book "Tuning the A-series Engine". He admits that the
muffler is louder than the stock muffler made by Leyland (a different
muffler from our TR6, but uses the same internal design for noise
control) but says that it is more than adequate in terms of noise level.
Remember, however, that overall noise level is heavily influenced by
your cam selection and headers. A long period cam will make MUCH more
noise than a stock cam, and headers will likewise make more noise than
an iron exhaust manifold.
BTW, the Leyland design uses restriction to provide the noise
control; make the exhaust pass through a limited number of tiny holes to
reduce the noise. Interesting that all three of his top rated mufflers
use baffling to control the noise, not restriction. In fact, all three
of his top rated mufflers are so called "3 pass" designs; the gasses
reverse direction twice so that they pass through the muffler a total of
3 times. The internal size of the muffler never drops down below the
inlet pipe, however, so there is never a restriction. What little back
pressure there is is created only by the gas itself as it reverses
direction. Very slick.
Cheers,
Vance
________________________________
From: samuelsma@aol.com [mailto:samuelsma@aol.com]
Sent: January 04, 2008 8:13 AM
To: Navarrette, Vance; 6pack@autox.team.net
Subject: TR6 mufflers
Vance:
At what RPM range does the restriction of the stock muffler become
noticeable? Also, do you have any personal experience actually hearing
any of the 3 recommended mufflers? I would like to avoid the
disappointment of creating a custom exhaust and then realizing that one
of these recommended mufflers is as loud as the Monza system I had on a
previous TR6.
Thanks.
Michael
'76 Tahiti blue
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