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Converting a roadster into another body

Discussion in 'Electric Conversions' started by pdemos, Jan 6, 2014.

  1. pdemos

    pdemos New Member

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    Looking for a reality check and any info I can get. My dream car build would be an electric Porsche 911 (preferably an early 70's model). I have located a selvage title Tesla Roadster. Would it be rediculous to try and convert the motor, batteries and electronics from the Tesla into a 911 restoration? Are there some contact or links anyone can suggest to get more information on what would be involved? Any help or info would be appreciated.
     
  2. RichardL

    RichardL Member

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    Check out 914world.com

    There is someone there converting a Porsche 914 to use a Roadster power train. 911 issues would be very similar.

    I'll try to find a link for you
     
  3. djp

    djp Roadster 2.0 VIN939

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    If it's salvage title then there's a good chance the battery is shot, which is a $40K replacement part.

    It's not impossible, but not easy. You'd probably be better off doing an EV conversion project with off-the-shelf parts rather than trying to shoehorn a Roadster drivetrain into a 911 frame.
     
  4. pdemos

    pdemos New Member

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    Can you really build a fast EV with what's available off the shelf? If I was to do this it would have to be reasonably quick. Also assume the Roadster's battery pack is a fair bit lighter and smaller than the Model S?
     
  5. djp

    djp Roadster 2.0 VIN939

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  6. dhrivnak

    dhrivnak Active Member

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    I would build such a conversion with off the shelf parts that you can get support for. I think one would have a lot of challenges to get it to work. For example one can not start a Roadster unless it detects that the charge port door is closed. I am certain there are many other such sensors you will have to wrestle with. With no documentation and likely little support you will have a challenge on your hands I do believe.

    PS I did have a converted BMW (EV West) that did very well in the Pikes Peak challenge and managed to eek past my Roadster in a 1/8 mile run so you can build a performance car with off the shelf parts that you can maintain.
     
  7. sranger

    sranger Member

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    I had a 1968 911L I should have converted to electric drive. However, a co-worker badgered me for years until I sold it to him.

    If I was going to do a conversion of a 911 I would use the HPEVS.com AC-35x2 Motor and Curtis controller. I would keep the 5 speed transaxle and simply use an adapter plate and coupler and keep the clutch. This system is a low voltage system 144 volts and is much safer for a DYI person to work with. I would use 48-50 CALB 180 AmpHr LiFePo4 cells. These are the safest chemistry you can use and do not require active thermal management.

    What you would have would be a 90-100 mile range car in the 3000lb weight class with 168hp and 188 ft-lb from 0-5000 rpm. This would make for a fast little 911. It would have programable regenerative breaking and you can even add a pressure switch on the brakes to add re-generation that increases as you press the brake pedal...

    You can buy almost every part you would need off the shelf except for the battery boxes. Total EV drive line cost would be about $25,000 with the batteries....
     
  8. qwk

    qwk Model S P2681

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    $25k is a lot of scratch for that little hp and range just for the drivetrain with no car included, considering used 1.5 Roadsters can be had for around $50k.
     
  9. TEG

    TEG TMC Moderator

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    #9 TEG, Jan 8, 2014
    Last edited by a moderator: Mar 13, 2016
    Energy density for the 18650 Li-Ion cells has been increasing. The smaller pack Model S (~60kWh) is probably fairly close in size and weight to the old Roadster (~53kWh) pack.
    Model S pack being flat under the floor makes it better for "packaging efficiency" and preserving interior space. Also flat pack under the floor gives lower center of gravity.

    - - - Updated - - -

    Using "off the shelf" (non-Tesla) parts, here is one example:
     
  10. sranger

    sranger Member

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    So you think buying a used roadster for $50k and putting that into a 911 is a better value?

    Did you miss the part where he wants an electric 911?
     
  11. pdemos

    pdemos New Member

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    May be his first drive in that 911 but it doesn't look quick. This build looks to require all the batteries to remain in the back. Isn't that putting a lot of weight behind which is kind of the 911 issue I would wish to fix by having low battery placement in the floor. Also yes $25k would be a lot to invest for only little power. I have been looking at salvage roadsters. Where can I get diagrams and info on the roadster chasis and battery placement, diagrams etc.
     
  12. sranger

    sranger Member

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    It is possible to do the swap, but the roadster batteries and motor are not going to work well in a 911. While it may have more hp and torque, the extra weight is going to cause slow acceleration. Having a five speed will be faster with less hp and torque than a single speed gear box...
     
  13. richkae

    richkae VIN587

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    Ignoring practicality, reliability and cost, it would be fun to have something that is custom and unique.

    Lots of inspiration here: National Electric Drag Racing Association
     
  14. djp

    djp Roadster 2.0 VIN939

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    The Roadster doesn't have low battery placement in the floor - it's a big box behind the seats. Schematics and engineering support are going to be tough to come by, since none of that information has been released by Tesla. We don't even have a service manual yet!

    Roadster - under the skin
     

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