robert nanzig wrote:
> I just got my new stainless exhaust system ( Falcon brand from VB )
> installed on my SV and am mildly dissapointed. I replaced my old one
> because it was annoyingly loud,had holes in it and was not proper.(
> assuming this new one IS proper ). The new one sounds very sporty but
> seems no quieter than the old, which had only one improper muffler
> rather than a muffler and resonator. And the new one sets up a low
> frequency vibration at 3300 rpms that could numb your butt if you hold
> the rpms steady. It smooths out considerably at 4000-4100. I've never
> driven another Alpine to know how it should sound or feel but does this
> sound correct?
> What is the purpose of the resonator? It looks like it would quiet
> things but the name name implies otherwise.
> Comments please. I'm disquieted with buyer's remorse.
>
> Rob Nanzig
> 67SV
Rob:
I waited to see if someone more knowledgeable might reply, and I would
also like to know more, but here's what I know about resonators.
As installed, they usually have two purposes: one is to make the car less
noisy, while the other is to "tune" the exhaust system by utilizing a
shaped chamber and/or packing and baffles to set up sound frequencies that
will either scavenge the combustion chamber by "pumping " out the exhaust
and producing low or negative back pressures, or actually increase back
pressure by including more baffles and make the noise reduction factor
paramount. (Apparently, increased or a certain level of back pressure may
be a good thing, but I don't understand why - Slower burning? More
complete combustion? Richer mixture?).
I have built some simple shaped-chamber resonators for people who were
into motorcycle and snowmobile racing using two-cycle engines. (The
scavenging function becomes much more important with two-cycle engines),
but I have also cut out and thrown away perfectly good resonators for hot
rodders and similar types who insisted resonators were just an impediment
in the exhaust. Also, many performance types seem much more interested in
the "powerful sound" production, rather than any real increase in power.
What you really want to know is should you put one in and will it cure
your problem. My guess (if you have eliminated frame contact resonance) is
that it could (and maybe that's why those old Rootes engineers put one in
in the first place!) However, there is a bewildering array of
chrome-plated junk to hang on the end of your tailpipe, and I have no idea
what to recommend. Maybe some of our racing people can expand on this,
since they usually use a specially designed tuned exhaust (resonator) with
no muffler.
Ron Tebo
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 11:01:26 CDT