[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Rolly Polly Physics... WAS Re: battery relocation question

Subject: Rolly Polly Physics... WAS Re: battery relocation question
From: roclist@accessconsulting.ca (Jason Adams)
Date: Wed, 26 Feb 2003 11:58:10 -0800
References: <20030226181939.14A1E45E7@sitemail.everyone.net>
I meant, "no matter how" as lower the c.g. if you can by whatever means,
i.e. remove sunroof, remove headliner, swap glass to plexi, sit yer fat ass
lower in the car, and if you can mount the battery lower than the stock
position.  All of these actions will lower the c.g. of the car, whether it's
practical, noticable, I won't say. I'm just talking hypothetically here.  I
haven't said anything about altering the first moment of inertia here, which
would also occur with any of the afore mentioned actions.  Is it good for
this? I don't know. What would be better? Placing the battery as far back to
help weight distribution, or closest to c.g. / c.m. to minimize rotational
inertia.  This is an important question for me, not saying I know the
answer, as my ice racer experiences large moments as I swing it through the
twisties on the track.  Insight from knowelegable folks is most welcome.
I'm inclined to mount the battery at the front of the spare tire well
(compromise between lowering cm and lowering rotational inertia) is this
correct? However if I wish to lower the rotational inertia more would it be
better to place the battery between the rear shock towers, (closer to the
yaw axis).  Or does this stuff matter at all because we are only messing
with a small percentage of the total mass. BTW, in attempts to lighten /
decrease rotational inertia (yaw axis) i have removed the bumpers.

Ain't Newtonian mechanics fun....

Jason Adams
Fahrvergnugen Forever! ;)
84 rocco 16v
93 320i
98 Z71

----- Original Message -----
From: "Haygood" <haygood@aemail4u.com>
To: "Jason Adams" <roclist@accessconsulting.ca>; "Drew Teague"
<roccnroll@hotmail.com>; <haygood@aemail4u.com>;
<rocco_crossing@hotmail.com>; <scirocco-l@scirocco.org>
Sent: Wednesday, February 26, 2003 10:19 AM
Subject: Re: battery relocation question


> So I'm sure it's not what you meant by "no matter how", but lowering the
C.G. or changing the weight distribution by adding weight is NEVER a good
thing.  Only mention it because I went ten rounds with some "engineers" in
school about this.  Finally won the arguement on the skidpad.
>
> So yeah, lower is better, and further back is better.  Which one wins is a
good question.  Only reason I didn't use the spare tire well was because I
keep a spare tire there.  Seemed like a good reason at the time. :)
>
> I'm a big fan of balancing weight distribution front-to-rear.  Maybe too
much of one, but we may never know.  I kinda figure that compared to real
sports cars, our cars are really far off on front/rear W.D, and not so bad
on C.G. height.  Just an opinion really.  Within the year I plan to recess
my battery into the trunk floor at the rear of the trunk, so I'll have both
accomplished before too long.
>
> BH
>
> --- "Jason Adams" <roclist@accessconsulting.ca> wrote:
> >I would expect that lowering the c.g. of the car is good no matter how
it's
> >done, that being said the lower the battery, the better...
> >
> >
> >Jason Adams
> >Fahrvergnugen Forever! ;)
> >84 rocco 16v
> >93 320i
> >98 Z71
> >
> >----- Original Message -----
> >From: "Drew Teague" <roccnroll@hotmail.com>
> >To: <haygood@aemail4u.com>; <roclist@accessconsulting.ca>;
> ><rocco_crossing@hotmail.com>; <scirocco-l@scirocco.org>
> >Sent: Tuesday, February 25, 2003 8:57 AM
> >Subject: Re: battery relocation question
> >
> >
> >> Just a quick question after reading this:  Would handling be better
with
> >the
> >> weight closer to the ground (i.e. spare tire well) or farther back to
> >> distribute the weight a bit more evenly?  Not having had much
experience
> >> with all this, I would imagine getting it closer to the ground would
> >reduce
> >> roll a bit, which I would think would be optimal.
> >>
> >> ...My $.02
> >>
> >> Drew
> >>
> >> **Drew Teague**
> >> Harrisburg, PA
> >>
> >> `84 8v Rocco --  "Bruise"
> >> `85 BMW 318
> >>
> >>
> >>
> >>
> >>
> >> >From: Haygood <haygood@aemail4u.com>
> >> >Reply-To: haygood@aemail4u.com
> >> >To: "Jason Adams" <roclist@accessconsulting.ca>,"Rhett Farnum"
> >> ><rocco_crossing@hotmail.com>, scirocco-l@scirocco.org
> >> >Subject: Re: battery relocation question
> >> >Date: Tue, 25 Feb 2003 08:22:26 -0800 (PST)
> >> >
> >> >Deep cycle means you can discharge it more without killing it.  They
are
> >> >used for things like trolling motors on boats that do a lot of work
> >between
> >> >charges.  You don't need that.  You want gell cell.
> >> >
> >> >As for mounting position, don't just worry about countering your
weight.
> >> >These cars have over 60% of there weight on the front end.  Counter
that!
> >> >Put the batt as far back as you can get it.  The whole "centered over
the
> >> >rear axle" thing is a mystery to me as well.  Sounds nice, but from an
> >> >engineering standpoint there is nothing magical about that area.
> >> >
> >> >The downside of placing it further back is that the further from the
CG
> >you
> >> >place things, the harder it is to rotate the car in a turn.  If, for
> >> >example, your car's weight distribution starts out at 65% front and
35%
> >> >rear, you are 15% away from the ideal of 50/50 (which is itself
> >debateably
> >> >ideal, but go with it).  Basic numbers I ran a while back (so they may
> >have
> >> >lost accuracy with time :) ), suggested that putting the batt behind
the
> >> >rear seat would make you something like 62/37, and putting it in the
rear
> >> >of the trunk did something like 60 or 61/whatever.  Keep in mind that
a
> >> >difference of "1" there is huge because we are only "15" away from the
> >> >ideal.
> >> >
> >> >So there is an incentive to move it far back.
> >> >
> >> >As for the increased rotational inertia, that batt., when in the rear
of
> >> >the trunk, is no further from the rear axle than it was from the front
> >> >axle.  The inertia gain is probably small compared to the inertia of
the
> >> >whole car, which is dominated by the engine hanging out in front of
the
> >> >front axle.  The increase in rotational inertia (really it's the first
> >> >moment of inertia we are talking about, to be tech-ish), would hurt
you
> >in
> >> >transitions, but then the improved weight distribution would help you
in
> >> >transitions as well as the rest of the turns.  Prolly close either
way,
> >and
> >> >either way is better than stock, but getting the battery further back
> >than
> >> >the rear seat is prolly a very good idea.
> >> >
> >> >HTH.
> >> >
> >> >Brian
> >> >
> >> >
> >> > >----- Original Message -----
> >> > >From: "Rhett Farnum" <rocco_crossing@hotmail.com>
> >> > >To: <scirocco-l@scirocco.org>
> >> > >Sent: Monday, February 24, 2003 2:17 PM
> >> > >Subject: Re: battery relocation question
> >> > >
> >> > >
> >> > >>
> >> > >> So, is a dry cell the same as a deep cycle? Or are they different
and
> >> >what
> >> > >> is the best to run in our cars.
> >> > >>
> >> > >> ALSO, I am thinking of putting my bettery where the back passenger
> >seat
> >> > >> would be inorder to counter my wieght and balance the car better
> >while
> >> > >> autoXing. What would be the best way to attach the box and where
to
> >run
> >> > >the
> >> > >> vent?
> >> > >>
> >> > >>
> >> > >> Peace Out,
> >> > >> Rhett
> >> > >> Rocco_crossing
> >> > >> '83 Rocco (autocross ready, 20 days till season opener)
> >> > >> '92 Olds Cutlass Ciera (DD)
> >> > >>
> >> > >>
> >> > >>
> >> > >>
> >> > >>
> >> > >> >From: "Josh20V" <mkii@nycap.rr.com>
> >> > >> >To: <scirocco-l@scirocco.org>
> >> > >> >Subject: Re: battery relocation question
> >> > >> >Date: Mon, 24 Feb 2003 16:35:06 -0500
> >> > >> >
> >> > >> >just as a side note, this is the one Im going with.
> >> > >> >
> >> > >> >http://www.jshouseofeuro.com/images/stinger.jpg
> >> > >> >
> >> > >> >Its a Stinger brand dry cell.
> >> > >> >
> >> > >> >24.9 lbs / 5" H x 6-9/16" W x 6-7/8" D
> >> > >> >
> >> > >> >Josh Able
> >> > >> >www.JsHouseOfEuro.com
> >> > >> >BrandNew Eurobumpers in stock
> >> > >> >check out the forums!
> >> > >> >----- Original Message -----
> >> > >> >From: "Vince Royer" <vince@performancecarstereo.com>
> >> > >> >To: "Joe Doty" <Joe.Doty@lcnetwork.com>; "Ryan H"
> ><rhock99@epix.net>;
> >> > >> ><scirocco-l@scirocco.org>
> >> > >> >Sent: Friday, February 14, 2003 7:21 PM
> >> > >> >Subject: RE: battery relocation question
> >> > >> >
> >> > >> >
> >> > >> > > Just a note on all this battery stuff.  Here's my take:
> >> > >> > >
> >> > >> > > I wanted to get the weight of the battery right between the 2
> >> >wheels
> >> > >and
> >> > >> >as
> >> > >> > > low as possible to lower the center of gravity.  In the future
I
> >> >think
> >> > >I
> >> > >> > > will cut out the well and make my own, but I'll wait for the
> >stereo
> >> > >work
> >> > >> >to
> >> > >> > > start that.  For now I dropped the battery box down into the
> >wheel
> >> > >well
> >> > >> >as
> >> > >> > > far forward as possible and scewed it down.
> >> > >> > >
> >> > >> > > I'm using 1/0 phoenix gold power cable, through a 350 amp
circuit
> >> > >> >breaker.
> >> > >> > > I have a distribution block up front sending 4 AWG to the
Starter
> >&
> >> >4
> >> > >> >AWG
> >> > >> >to
> >> > >> > > the Alternator.  I used the battery I had, it has a vent hose
> >which
> >> >I
> >> > >> >routed
> >> > >> > > out the bottom.
> >> > >> > >
> >> > >> > > I also have another neat trick.  I recently had my car stolen
and
> >> > >really
> >> > >> > > don't want it happening again. If a theif cuts your battery
> >cable,
> >> > >alarm
> >> > >> > > goes bye-bye.  So I ran a second 8 gauge cable from the
battery
> >> > >directly
> >> > >> > > into the main power input from the fusebox.  That way I was
able
> >to
> >> > >> > > eleminate the old corroded wire coming through the firewall.
> >> >Suddenly
> >> > >> >all
> >> > >> > > my electronic devices performed better - like all the
> >> >bulbs/wipers/fan
> >> > >> >etc.
> >> > >> > > I guess I freed up some electrons, but the biggest thing I
gained
> >> >was
> >> > >> >the
> >> > >> > > security.  Now there is no way of disabling the alarm from
> >outside
> >> >the
> >> > >> >car.
> >> > >> > >
> >> > >> > > Cheers!
> >> > >> > >
> >> > >> > > Vince
> >> > >> > >
> >> > >> > >
> >> > >> > >
> >> > >> > > -----Original Message-----
> >> > >> > > From: scirocco-l-admin@scirocco.org
> >> > >> > > [mailto:scirocco-l-admin@scirocco.org]On Behalf Of Joe Doty
> >> > >> > > Sent: Friday, February 14, 2003 2:29 PM
> >> > >> > > To: Ryan H; scirocco-l@scirocco.org
> >> > >> > > Subject: RE: battery relocation question
> >> > >> > >
> >> > >> > >
> >> > >> > > I used a bench vise.  Worked great!
> >> > >> > >
> >> > >> > > Joe Doty
> >> > >> > > IT/Development
> >> > >> > > joe@lcnetwork.com
> >> > >> > >
> >> > >> > > > -----Original Message-----
> >> > >> > > > From: Ryan H [mailto:rhock99@epix.net]
> >> > >> > > > Sent: Friday, February 14, 2003 1:30 PM
> >> > >> > > > To: scirocco-l@scirocco.org
> >> > >> > > > Subject: Re: battery relocation question
> >> > >> > > >
> >> > >> > > > All this battery talk brings about an interesting question
of
> >> >mine:
> >> > >I
> >> > >> > > > bought the cheapo Summit kit, what kinda tool should I use
to
> >> >crimp
> >> > >> > > the
> >> > >> > > > end connectors (battery terminal connections are pre-crimped
> >> > >already)?
> >> > >> > > I
> >> > >> > > > don't think my trusty wire cutter/crimper will work for 2
gauge
> >> > >wire.
> >> > >> > > ;)
> >> > >> > > >
> >> > >> > > >
> >> > >> > > > _______________________________________________
> >> > >> > > > Scirocco-l mailing list
> >> > >> > > > Scirocco-l@scirocco.org
> >> > >> > > > http://neubayern.net/mailman/listinfo/scirocco-l
> >> > >> > >
> >> > >> > > _______________________________________________
> >> > >> > > Scirocco-l mailing list
> >> > >> > > Scirocco-l@scirocco.org
> >> > >> > > http://neubayern.net/mailman/listinfo/scirocco-l
> >> > >> > >
> >> > >> > >
> >> > >> > > _______________________________________________
> >> > >> > > Scirocco-l mailing list
> >> > >> > > Scirocco-l@scirocco.org
> >> > >> > > http://neubayern.net/mailman/listinfo/scirocco-l
> >> > >> > >
> >> > >> >
> >> > >> >
> >> > >> >_______________________________________________
> >> > >> >Scirocco-l mailing list
> >> > >> >Scirocco-l@scirocco.org
> >> > >> >http://neubayern.net/mailman/listinfo/scirocco-l
> >> > >>
> >> > >>
> >> > >> _________________________________________________________________
> >> > >> The new MSN 8: advanced junk mail protection and 2 months FREE*
> >> > >> http://join.msn.com/?page=features/junkmail
> >> > >>
> >> > >>
> >> > >> _______________________________________________
> >> > >> Scirocco-l mailing list
> >> > >> Scirocco-l@scirocco.org
> >> > >> http://neubayern.net/mailman/listinfo/scirocco-l
> >> > >>
> >> > >
> >> > >
> >> > >_______________________________________________
> >> > >Scirocco-l mailing list
> >> > >Scirocco-l@scirocco.org
> >> > >http://neubayern.net/mailman/listinfo/scirocco-l
> >> >
> >> >_____________________________________________________________
> >> >!!!!FAST, FREE AND HOT!!!!
> >> >for the best free email site on the web
> >> >http://www.aemail4u.com
> >> >
> >> >_____________________________________________________________
> >> >Select your own custom email address for FREE! Get you@yourchoice.com
> >w/No
> >> >Ads, 6MB, POP & more! http://www.everyone.net/selectmail?campaign=tag
> >> >
> >> >_______________________________________________
> >> >Scirocco-l mailing list
> >> >Scirocco-l@scirocco.org
> >> >http://neubayern.net/mailman/listinfo/scirocco-l
> >>
> >>
> >> _________________________________________________________________
> >> Help STOP SPAM with the new MSN 8 and get 2 months FREE*
> >> http://join.msn.com/?page=features/junkmail
> >>
> >>
> >> _______________________________________________
> >> Scirocco-l mailing list
> >> Scirocco-l@scirocco.org
> >> http://neubayern.net/mailman/listinfo/scirocco-l
> >>
> >>
> >
> >
> >_______________________________________________
> >Scirocco-l mailing list
> >Scirocco-l@scirocco.org
> >http://neubayern.net/mailman/listinfo/scirocco-l
>
> _____________________________________________________________
> !!!!FAST, FREE AND HOT!!!!
> for the best free email site on the web
> http://www.aemail4u.com
>
> _____________________________________________________________
> Select your own custom email address for FREE! Get you@yourchoice.com w/No
Ads, 6MB, POP & more! http://www.everyone.net/selectmail?campaign=tag
>
> _______________________________________________
> Scirocco-l mailing list
> Scirocco-l@scirocco.org
> http://neubayern.net/mailman/listinfo/scirocco-l
>
Follow-Ups:
- Rolly Polly Physics... WAS Re: battery relocation question
  - From: sfwilliams@comcast.net (Scott F. Williams)
References:
- battery relocation question
  - From: haygood@aemail4u.com (Haygood)
Prev by Date: [Re: idling, running problems...HELP before I get killedin t raffic!!!!!]
Next by Date: Cars
Previous by thread: battery relocation question
Next by thread: Rolly Polly Physics... WAS Re: battery relocation question
Index(es):
- Date
- Thread