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Discussion Starter #1
I was looking at the rear uni-body of my 1998 Chevy
metro.

It just seems if I cut it out, and welded in a nice
smooth box. I could get a very space efficient battery
box.

However, I guess all those hills/valleys in the uni
body add strength.

I was thinking just cut it out and then flip and then
maintain the original design?


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Discussion Starter #3
What I meant be flip was to rotate the sheet metal
that makes up the back seat and trunk and rotate that
180 degrees.

What kind of welding rod could I use? Does it have to
be spot welded?


--- Sean Korb <[email protected]> wrote:

> On 8/20/07, mike golub <[email protected]> wrote:
> >
> > I was looking at the rear uni-body of my 1998
> Chevy
> > metro.
> >
> > It just seems if I cut it out, and welded in a
> nice
> > smooth box. I could get a very space efficient
> battery
> > box.
> >
> > However, I guess all those hills/valleys in the
> uni
> > body add strength.
> >
> > I was thinking just cut it out and then flip and
> then
> > maintain the original design?
>
>
> What do you mean by "flip"?
>
> If you alter the unibody on these small cars, be
> *VERY* careful. Unexpected
> items such as wheel houses and gas tank pans can be
> considered stressed
> members. If you happen to have a straightforward
> design (like a 1965
> Mustang, for instance), you can just tie the torque
> boxes to the frame rails
> and insert appropriate bracing. I did this for my
> ICE car at
> http://suprang.com when I installed an independent
> rear suspension. But I
> can't endorse this sort of bad behavior. If you
> miscalculate, botch a weld,
> or underestimate a stress point, you could do great
> damage to yourself and
> others.
>
> Be careful.
>
> --
> Sean Korb [email protected] http://www.spkorb.org
> '65, '68 Mustangs, '68 Cougar, '78 R100/7, '71
> Pantera #1382
> "The more you drive, the less intelligent you get"
> --Miller
> "Computers are useless. They can only give you
> answers." -P. Picasso
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Discussion Starter #5
This is what Randy's Geo kit at www.canev.com does. You cut out where
the gas tank and spare tire were, and he has a box that drops right into
place there, where you weld or bolt it. No keeping the old cutout and
flipping it necessary.

Bill Dennis

mike golub wrote:
> I was looking at the rear uni-body of my 1998 Chevy
> metro.
>
> It just seems if I cut it out, and welded in a nice
> smooth box. I could get a very space efficient battery
> box.
>
> However, I guess all those hills/valleys in the uni
> body add strength.
>
> I was thinking just cut it out and then flip and then
> maintain the original design?
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>

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Discussion Starter #6
Mike:

You can cut sheet metal out of a unibody but you need to keep the structural portions of the unibody intact.
The structural portions are "closed sections" that are constructed of sheet metal folded up and spot welded together forming a box that resembles a frame rail. Keep in mind that if you do remove single thickness sheet metal, you may need to provide a way to stablize the closed sections (box sections or sheet metal frame rails) that they are attached to. In other words, you have to be very careful about what you cut out.

The other thing to keep in mind is that if you do bend up a sheet metal battery box, you have to distribute the load evenly to the sheet metal box sections.

You may be able to stiffen the whole area by bending up a box frame that incorporates closed sections that fit on the unibody sheet metal frame sections. A well constructed battery box can replace a lot of the stiffness of the (single thickness) sheet metal that is removed.

Dana





-------------- Original message ----------------------
From: mike golub <[email protected]>
> I was looking at the rear uni-body of my 1998 Chevy
> metro.
>
> It just seems if I cut it out, and welded in a nice
> smooth box. I could get a very space efficient battery
> box.
>
> However, I guess all those hills/valleys in the uni
> body add strength.
>
> I was thinking just cut it out and then flip and then
> maintain the original design?
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev

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Discussion Starter #7
Solectria added battery boxes in the spare tire well and under the back seat
of the Metro, and I'm pretty sure they passed NHTSA certification. I
wouldn't sweat it.
David Roden - Akron, Ohio, USA
EVDL Administrator

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