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Electric (Hybrid) 356

FM Former Member

Hopefully I am in the right place...

I am looking for advice and Ideas - primarilly regarding 356 frame/chassis options and the resulting replica body options which are open to me.

I am an Electronics Engineering Student building an electric daily driver as my thesis project. For the curious in the crowd, here are some requirements (!), and Goals (*):

! Light, Light, Light!
* Vehicle Weight (without Drivetrain) < 450kg (990lbs)

! Rigid Frame
! Must Carry Battery Weight = 322kG! (708 lbs)!
! = 46 evenly Distributed Car Batteries
! They are each 194mm x 155mm x 127 (7.6"x6.1"x5")
(Phosphate-Lithium-Ion, if you were wondering)

* Small & Aerodynamic
* (But NOT a "golf cart" Nor "Go Cart"!)

* Easily Modifiable

* Supportive Builders community

! Reasonably priced & Available components.
I need to minimize the number of custom parts.
(Body parts, Chassis, Suspension, trim, etc.)

* Shooting for 300km (186mi) highway Range.

* Register-able in Canada...



I have little Automotive mechanical experience. I plan to hire friends/family to do most of the build-up. My brother has built several custom vehicles and my friend owns a Porsche/BMW/VW rebuild & repair shop - But this will be a learning experience for me!

SO - Which replica is the lightest? Do you see any glaring problems with using a 356 replica as my base? Suggestions?

Trevor.
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FM Former Member

Hopefully I am in the right place...

I am looking for advice and Ideas - primarilly regarding 356 frame/chassis options and the resulting replica body options which are open to me.

I am an Electronics Engineering Student building an electric daily driver as my thesis project. For the curious in the crowd, here are some requirements (!), and Goals (*):

! Light, Light, Light!
* Vehicle Weight (without Drivetrain) < 450kg (990lbs)

! Rigid Frame
! Must Carry Battery Weight = 322kG! (708 lbs)!
! = 46 evenly Distributed Car Batteries
! They are each 194mm x 155mm x 127 (7.6"x6.1"x5")
(Phosphate-Lithium-Ion, if you were wondering)

* Small & Aerodynamic
* (But NOT a "golf cart" Nor "Go Cart"!)

* Easily Modifiable

* Supportive Builders community

! Reasonably priced & Available components.
I need to minimize the number of custom parts.
(Body parts, Chassis, Suspension, trim, etc.)

* Shooting for 300km (186mi) highway Range.

* Register-able in Canada...



I have little Automotive mechanical experience. I plan to hire friends/family to do most of the build-up. My brother has built several custom vehicles and my friend owns a Porsche/BMW/VW rebuild & repair shop - But this will be a learning experience for me!

SO - Which replica is the lightest? Do you see any glaring problems with using a 356 replica as my base? Suggestions?

Trevor.
execk2execk2
It would be cool to see it on a 356 which without motor and transmission and gas tank would probably be close to your weight requirements. Where are you located? There are members here that can have you look at their toys. Having the batteries evenly distributed means you can even use a stock VW pan and build a shelf in the engine compartment and go through to the rear seats and add some more in the front to even out weight. Like a 60 rear and 40 front. Heck that might even handle like mad.

Are you going to have the discs create energy and all that jazz? Maybe paint the car with photovoltaic capture paint so that it recharges while parked. (not sure if that's been invented yet)

Sound like an awesome idea.

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  • bob
WOLFGANGWOLFGANG'89 CMC FWB, FL Supporting Member
The sub frame (which came mounted to the fiberglass body on a CMC roadster is pretty substantial and with a VW pan could hold the weight. If I recall the shipping weight of a CMC kit was 1100# - without pan/suspension/trans/engine so it isn't light. The MGTD/Gazelle would probably be lighter but not as aerodynamic. Seems I've heard of some Bradley GTs with electric power running around --- they are considerably lighter. Check out the build manuals for CMC online here in the Library. Do a Google search on Brubaker Box --- Popular Science or Mechanics had a spin off that was built with foam panels on a VW pan. Suspect Foam with a fiberglass coating would be lighter weight and actually have more interior room - plus it could be built cheap.
FM Former Member
[Ricardo] Thanks for the Floorplan!

It underlies less of the vehicle than I thought. I probably would need to build pretty significant support structures to extend the battery holding area into the engine and front bonnet corner spaces :/

If anyone has any other diagrams showing the pan in the vertical dimension - that would be appreciated too.

[Theron] Thanks for the heads up!
I did not realise that the floorpan needed shortenning :( I'll look through the Library section on this site to see if I can figure out where the length is removed... can I assume that the floor pan that Ricardo posted above is an un-shorened one?

[Lane], [Wolfgang] the additional info is appreciated. I was also looking at the Spyder style, but I prefer the look of the 356 and I didn't think there would be that much weight difference.

Does anyone know which 356 Body is the lightest? I fear that due to the number of batteries I need to squeeze in there, I'll be forced out of using a pre-existing pan anyway. I'm in Canada, so I favored the Intermechania, but it describes a steel-reinforced body which sounds quite heavy... and they have not responded to the email I sent.

Also, (I realise this is a long shot) has anyone come accross any wind-tunnel analysis info on the 356? I'd love to find a Coefficient-of-Drag or Frontal-Area equivalent for that body.
FM Former Member
The drag data is available in the book "Porsche 356, Driving in its Purest Form" by Dirk-Michael Conradt.

The engineers at Porsche put a bunch of their 356s into the wind tunnell in the 1980s to see what they came out at. Depending on the configuration (coupe, speedster, etc.), the drag coefficient ranges from 0.296 to 0.46.

The book has a whole table of data.
J jgajdecki

I think this is a great idea, and I actually wanted such a vehicle rather than the water cooled gas powered one I ordered from Intermeccanica last year.

You should consider a Speedster rather than a Convertible D as it has fewer bits and therefore weights a little less, and looks rather smashing without the rag top. If you can get by without the top you would realize a weight savings, but a drag increase. Finally, the steel frame is heavy, but the jigs exist and if you are building a test car you may want to look into welding with aluminum. It is more expensive and much more difficult, but people are out there who do it all the time. I
FM Former Member
The Aluminium chassis is a brilliant thought, and I really appreciate the advice on calling Henry directly; I would still prefer IM to turn out to be my best choice. Thanks, John!

I'll call Henry tomorrow while I'm visitting my father to plan this out more. Although, if IM is busy, they may not be too eager to start something heavily customized.

One of the my friends does custom choppers and has welded up a few aluminium motorcycle frames with good success. (He does it for the look of a huge tube without the weight, I think) He's an outstanding welder with experience registering scratch-built vehicles; I can't believe I never thought to talk to him about doing a 356 frame for me!

If I got him to replicate the dimensions of a shortened VW pan would there be multiple body options available to me? Or does each Manufacturer use significantly different body moulds?
(Different enough that each one means re-designing the frame from scratch)
FM Former Member
Yes - it would be dramatically easier to register if I start with a VW pan, my concern is the torsion on the pan itself with significant weight on the opposing corners... of course this may be fine, I just haven't looked into it yet. (my father is a mechanical engnineer, & we are meeting this weekend to discuss this).



I guess what I need is an AutoCad mock-up of a VW pan so I can lay out exactly where all of the batteries will go while considering typical 356 body & mounting points.



I am in Saskatchewan, Canada. If you know the area, The Electronics prototyping will be done in MooseJaw, and the Mechanical and final assembly done in Regina. I travel back and forth to Saskatoon a lot too.



Yes, since I'm in Electronics Engineering, not Electrical or mechanical, the core of this project is to develop an adaptive computer controlled power management system with n number of power sources, both AC and DC. The initial power reclaimation systems include heat and kinetic regenerative braking & photovoltaic (Although the paint you speak of is not on the market yet... and it's more of a "surface lamination" than a paint).



If anyone knows where I can find a pre-made autoCad drawing of a VW floor-pan, Please let me know!
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