> Just wonderin'. You know, we post a lot about how others' noise is obnoxious.
> How about our own?

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~*~ The A.S.T. Motto ~*~
"Never wrestle with a pig, you get dirty and the pig enjoys it."
~*~
"Robin" <rpatrick@Nospam.com> wrote in part:
>Valid point of this were a gasoline engine. It is diesel and a cat serves no
>purpose nor are they required on diesel motors. That is why I can get it
>inspected and pass without one. They also stopped installing them on the
>newer trucks because they serve no purpose.
I assumed it was a gasoline engine since it had a catalytic converter! But why
do they put such an expensive device on a vehicle if it does no good?
Manufacturers aren't known for that. I used to know the ends and outs of the
automotive noise and emissions business, but not any more.
>Yes I understand you concern. Placing a large"tip" on a vehicle will
>increase the noise as would a megaphone to the mouth. Enlarging the entire
>exhaust system doen not do this.
I'm not sure I understand. You may well be right.
>Have a nice day Jim
I have. Hope you have, too.
(PS: I used to work for GM at their Research Labs. I worked in psychoacoustics
and, at one point, developed a model of vehicle noise based on changes in
vehicle design and explored the ways GM could meet various proposed noise
standards. I also learned everything there was to know about tire noise. But
that was a long time ago and before tinnitus.)

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Jim Chinnis / Warrenton, Virginia, USA
Want to discuss Meniere's? See http://groups.yahoo.com/group/MenieresDG
Martin - 13 Jul 2003 06:38 GMT
>I have. Hope you have, too.
Jim, with the pain I see in your eyes, are you able to have a nice
weekend?
What was it Jim? Was it your mom or your dad?
I sent a magazine to you - "Boy's Life." Do enjoy it as I know how you
do.
Martin Aquinas - changing minds one American at a time
"We cannot forget. We cannot forgive ... We went
through too much. They will have a sentence of their own:
Remembrance."
Border...Language...Culture....QUICK!
Robin - 13 Jul 2003 15:38 GMT
> "Robin" <rpatrick@Nospam.com> wrote in part:
>
[quoted text clipped - 7 lines]
> Manufacturers aren't known for that. I used to know the ends and outs of the
> automotive noise and emissions business, but not any more.
As I understand it (in other words heresay) they installed them for Gove
Regs and then got the regs changed because it did not do any good.
> >Yes I understand you concern. Placing a large"tip" on a vehicle will
> >increase the noise as would a megaphone to the mouth. Enlarging the entire
> >exhaust system doen not do this.
>
> I'm not sure I understand. You may well be right.
Again, I think... that it will lower the tone but not increase the volume.
Either way the effect is minimal. I am making the change to lower the EGT at
the turbo inlet so when I increase the engine output I do not burn the
tubine blades.
> >Have a nice day Jim
>
[quoted text clipped - 5 lines]
> standards. I also learned everything there was to know about tire noise. But
> that was a long time ago and before tinnitus.)
Sounds like interesting work. Do you think this had anything to do with your
"T" or was it that long ago.
Robin ;-)
Jim Chinnis - 13 Jul 2003 17:50 GMT
"Robin" <rpatrick@Nospam.com> wrote in part:
>As I understand it (in other words heresay) they installed them for Gove
>Regs and then got the regs changed because it did not do any good.
I don't think so. The emissions regs are performance based only. In other
words, data must be presented to the EPA showing that the vehicles can be put
through a particular operating cycle on a dynamometer and meet the emission
output limits. Then, at a later mileage, they have to do it again. The gov't
does not specify how they meet the limits. The choice of installing a
catalytic converter on a diesel had to be because the test vehicles wouldn't
pass emission requirements without it. The manufacturers aren't idiots with
their own money.
>> >Yes I understand you concern. Placing a large"tip" on a vehicle will
>> >increase the noise as would a megaphone to the mouth. Enlarging the
[quoted text clipped - 7 lines]
>the turbo inlet so when I increase the engine output I do not burn the
>tubine blades.
I'll call one of my old buddies who is still in this business and report back
if I he has an answer.
>> (PS: I used to work for GM at their Research Labs. I worked in
>>psychoacoustics
[quoted text clipped - 5 lines]
>Sounds like interesting work. Do you think this had anything to do with your
>"T" or was it that long ago.
It was 16 years before my T hit. I was never exposed to loud noise even though
I researched it.

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Jim Chinnis / Warrenton, Virginia, USA
Want to discuss Meniere's? See http://groups.yahoo.com/group/MenieresDG
You're the pig. Stop calling people pigs in every post, you hostile pig.