Greetings Barry; I concur in trying to quiet down my car's exhaust note. I do
not want to irritate my neighbors when I leave for work in the early mornings
and my car does not run well when cold under 2000 rpm. I am currently in the
process of upgrading my 2.5L Spit bodied GT-6's Monza exhaust system. Actually
all that is left of the Monza system are the pair of dual exhaust tips. I a
previous attempt to quieten the exhaust I replaced the rear Monza glass packs
with Dynomax Mini-turbos. In preparing for the latest changes I did some
research. I spoke with Borla's tech rep and was told that the longer 30in?
silver bullet would give a noticeable sound reduction over the 18 in. version
with an insignificant increase in backpressure. I questioned the validity (I'm
cheap and my spouse discourages me in spending money on the "toy car") of buying
a SS glass pack. Brian S. at Power British suggested a turbo tube muffler. I
purchased a 24 in. long turbo tube (3 in. OD, true 2.0 ID, Thrush brand from
Jegs, about $30) and have installed it as a resonator between the X-frame rails.
THe turbo tube replaces the 2.75 OD, 13 in. long Monza resonator (with a tiny
1.3 in. ID).
Years ago when I installed the Monza system I turned down the lower flange of
the GT-6's frame. This increased the clearance between the frame rails to about
3.75 in. at the narrowest point. By turning down the lower flange I
(potentially) reduced the frame's stiffness cross car (in side impact) and
increased its stiffness in for/aft bending. I consider the subtle if any
increase in for aft stiffness to be a plus and by the time the frame provides
any significant protection in a side impact I would already be very dead.
Date: Fri, 07 Apr 2000 10:21:03 -0700
From: Joe Curry <spitlist@gte.net>
Subject: Re: Exhaust resonators
Barry,
At the narrowest point, the frame edges (at the bottom) are about 3.25" apart.
So it's doubtful you would be able to get a 3" resonator in there without it
rattling against a frame member.
Joe
Barry Schwartz wrote:
>
> I'm getting ready to install the Borla muffler on the Spitfire, and still
> have a slight concern about the noise level. I know, I know, but I'm not a
> kid anymore, and I just cant stand that droning associated with the usual
> straight through exhaust.
> Borla makes a resonator, that I think I can install before the muffler.
> Question 1. Will a small (18 inch long) resonator actually help enough to
> justify the cost ($95) and installation work (minor)? I do know that the
> GT's did use one on early models, so I assume they are of some benefit
> Question b. Does anyone have the minimum distance between the frame at
> it's narrowest section?
>
> Barry Schwartz (San Diego) bschwart@pacbell.net
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