[alfa] POSSIBLY Incomplete Message: alfa-digest V10 #258

[RonHorowitz <RonHorowitz@xxxxxxxxxxxxxx>]

Forum for Discussion of Alfa Romeos, etc.
       Richard Welty <rwelty@domain.elided>
       Digest Coordinator

Contents:

     Subject: [alfa] torsion bar mathematics?
     Re: Subject: [alfa] torsion bar mathematics?
     [alfa] Re: Fast Idle
     [alfa] Starting 74 spider after sitting..
     Re: Subject: [alfa] torsion bar mathematics?
     [alfa] Re:Torsion Bar Rates
     [alfa] Alfa Digest Clubs: regular posting
     [alfa] Re: Rotisseries
     [alfa] Distributor questions
     [alfa] Alfetta torsion bars
     RE: [alfa] Starting 74 spider after sitting..

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Date: Sun, 1 Aug 2004 23:37:51 -0400
From: RonHorowitz <RonHorowitz@domain.elided>
Subject: Subject: [alfa] torsion bar mathematics?

>From: Richard Welty <rwelty@domain.elided>
>Subject: [alfa] torsion bar mathematics?
>
>does anyone have the worked-out math formulas relating torsion bar
>diameter to conventional coil spring rates

Off the top of my head, so I'd verify it, I'd say proportional to the
modulous times the forth power of the diameter.

>one of the things i want to address is the torsion bar vs coil over
>issue

I'd say that if you have to run torsion bars, you're always going to be at
a disadvantage compared to the guys running coil overs. You'll have three
or four spring rate options, whereas someone running coil overs can buy
virtually any spring rate one could imagine. If the rules are intended to
level the playing field and make all the cars in the group competitive, you
could argue for an exception. (Or, you could buy whatever car happens to be
winning in the class you want to run, but that's another subject!)

RUN

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Date: Sun, 1 Aug 2004 23:53:26 -0400 (EDT)
From: Richard Welty <rwelty@domain.elided>
Subject: Re: Subject: [alfa] torsion bar mathematics?

i should have been clearer in my original posting.

the relationship between a coil spring and a torsion bar is not
a particular mystery.

what is an issue is the math describing the behavior of a spring
where it is inserted into a complex of control arms, and the
effective spring rate is different depending on where it appears
in the system. in an alfetta, a torsion bar which is coaxial with
the inner pivot of the lower control arm is in a very different
place from, say, a coilover attached to the lower control arm
that passes through a hole in the upper control arm and then
attaches to the body.

this is the math i'm after.

somewhere buried in my inbox i have something Douglas
Milliken sent me on the subject back when my interest was
more theoretical and less practical. it may take me a while
to dig that up, i think it may have been back when i was
running w2k on this laptop, so digging that out of my old
eudora inbox may be a bit of a challenge. this is assuming
that i can find that inbox and that i'm guessing right about
which one it's in.

richard
- --
Richard Welty
rwelty@domain.elided
Averill Park Networking
518-573-7592
    Java, PHP, PostgreSQL, Unix, Linux, IP Network Engineering, Security

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Date: Mon, 02 Aug 2004 00:04:39 -0400
From: Michael Tiefenback <tiefenback@domain.elided>
Subject: [alfa] Re: Fast Idle

Chris Sasso wrote:


     Date: Sun, 01 Aug 2004 17:27:06 -0400
     From: "Chris Sasso" <Chris.Sasso@domain.elided>
     Subject: [alfa] fast idle

     Hi All,

     My '87 Spider would not start so I went through the protocol
     to test
     the various Bosch FI components.  I ended up finding the
     Auxilliary Air
     Valve closed when cold, so I loosened the nut forced it open
     (per
     www.oldebottles.com)and tightened the nut. My Spider started
     instantly
     on the first crank but now has a fast idle.  Is the Aux Air
     Valve
     possibly causing this fast idle?  I'd rather not by a new one
     for $250
     if I do not need one.  It did not idle fast before the fix
     although it
     was very difficult to start.

     Also, when cornering I get a hesitation as I accelerate out of
     the
     corner.  Any thought on the cause?

I went through all of this logic recently, so I'll give you the (however
dubious) benefit of my present understanding.  The AuxAirDevice (AAD) is
a bypass around the throttle for metered air.  The throttle should be
_closed_ when it is supposed to be closed.  You might want to start
there, and with the throttle sensor switch.  The AFM should accomodate
all of this air flow with appropriate fuel.  The idle throttle
adjustment (which check) is another bypass for metered air.  The idle CO
is a bypass for _unmetered_ air to help correct any deficiencies in the
AFM and O2 sensor functions at idle (low flow).  The AAD is set to
satisfy the need of the engine for more air when it is cold.  The ECU
supplies proportionally more fuel.  It must be temp dependent, or proper
cold idle settings will give too high a warm idle.  The oldebottles page
suggests cleaning out the AAD periodically with solvent.  Try setting
the warm idle with the idle adjustment, and get a grommet for the
insides if you don't have one.  I didn't.  The interplay between the
fixed idle air bypass and temp-dependent AAD is probably not
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