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Discussion Starter · #1 ·
I purchased a 2014 Model S at salvage. I stripped it down to the skateboard chassis, and I am now reinforcing it so that is can become a convertible. The car that I am planning is based upon the Maybach Cabriolet 6 concept car. I am lowering the rear shock toweres, and hope to use as much of the Tesla systems as possible. I will use the rear drive unit, which has only 44K miles on it, with an EV Controls aftermarket controller. I hope to use the Tesla Bosch power steering unit, if I I can figure out a fake CAN bus signal, same for the brake booster and AC compressor. I will post pictures if the forum allows. I would appreciate any advide. I have found hundreds of builds that use the Tesla drive unit, but none that use the Tesla chassis. Thanks
 

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The ABS module, iBooster, steering and the yaw sensor in the middle of the cabin all live on the same can network so if you keep all that intact then you'll have half a shot at making it work. Pretty keen project!
 

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Discussion Starter · #3 ·
the circuits are not intact. I had to move the firewall back two feet, so I had to disconnect everything. I do not plan to use the Tesla MCU (the main controller with the touch screen) as there are just too many sensors and things that would be gone. So, either I find a fake CAN bus signal source for the steering rack, or I will not be able to use the power function. I can add an aftermarket electric steering unit like Unisteer makes, but I hoped to avoid that hassle and expense. Whatever it takes, I guess. It will be two years, probably, before I need it, so maybe in that time someone will sell a CAN bus overide. I have lots of aluminum to bend and weld in the mean time. Thanks
 

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You're not making any sense. "I had to move the firewall back two feet"

Impossible. The firewall meets the A- and door-pillars. The car would only have a back seat. The steering column would need to get stretched. The battery pack chopped and completely redone.

Use of the Blender sketch program gone wild. There's no way to do what you suggest.
 

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Discussion Starter · #8 ·
I am seriously bracing the frame. I will post pictures of that when I finish the welding. Yes, the steering shaft will be lengthened. The firewall is removed mostly intact, but is just sitting in place until the frame bracing is done. The firewall includes the front door hinges, which will have beefy aluminum supports. I am going to make longer doors by cutting the front and back doors and putting them together. Door glass will have to be custom, and that will be a serious hassle.. The Tesla windshield is too wide and long, so I will cut that out once the firewall is fixed in position.
 

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You might be better off finding a more suitable windshield and frame than sticking with the Tesla.

Ambitious & impressive.

Apologize for thinking you were a nutjob who didn't know what he was doing. You're a nutjob for what you are doing 😂 ...no sane person would do this...love it.
 

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Discussion Starter · #12 ·
I never claimed to be sane! But, I am committed to this, whatever it takes. I will need and appreciate advice from this forum. I built two Factory Five Racing replica cars, and I could not have done those without help from that blog. And, I tried to help others on that venue. Electric vehicles are a new frontier. Where is the fun in doing something easy?

By the way, my donor Tesla cost $12K, so far I sold the main battery for $8K and some other parts for $2k.
 

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Discussion Starter · #16 ·
I sold the battery for several reasons. First, this build will likely take 3 years. It will go faster after I retire next year, but still probably 3 years. The battery would degrade over that time period. Second, the high voltage disconnect circuit makes it useless unless that circuit can be overridden. If anyone knows how to do tha t please advise. Third, the weight distribution would be off, with too much weight towards the rear.

my tentative plan is to put some aftermarket batteries in an empty Tesla battery pack and put it back into position and the rest in the empty space in front of the firewall as a brick. That should allow for equal weight on all four wheels. I plan to use the existing Tesla coolant pumps and radiators. I need at least 80 kWh of battery I think.
 

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I sold the battery for several reasons.
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Third, the weight distribution would be off, with too much weight towards the rear.

my tentative plan is to put some aftermarket batteries in an empty Tesla battery pack and put it back into position and the rest in the empty space in front of the firewall as a brick. That should allow for equal weight on all four wheels.
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I need at least 80 kWh of battery I think.
The Tesla Model S 85 kWh pack (prior to whatever they changed this year and with the Plaid) fills the wheelbase putting roughly the same load on each axle, but slightly more on the front because the pack stacks two modules as forward as possible. With a drive unit only at the rear, and the body rear-biased, the car would be moderately rear-heavy... which is fine. At some point someone started this notion that 50:50 weight distribution is ideal, and while it's reasonable for an AWD or RWD car, it's not the ideal for every vehicle. Typical high-performance RWD cars are at least slightly rear-heavy without the driver, and more rear-heavy when occupied.

Just using the stock Tesla battery would provide the required energy, would be lower than any other configuration, and would result in good weight distribution.
 

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Discussion Starter · #18 ·
I agree that using a Tesla main battery would be simplest, but how to overcome the high-voltage disconnect circuit? Has anyone accomplished this? A perhaps 60/40 weight to the rear wheels would be fine. I suppose that I could finish the car then check the corner weights. If it is off by more, could always add more battery modules in front of the firewall. Thanks
 

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Discussion Starter · #20 ·
Not sure what you mean by high voltage disconnect circuit. Are you talking about a crash disabled pack? $35 part & you're up and running...
The high voltage interlock loop. My understanding is that it disables the battery and all high voltage components unless there is a CAN bus signal. Is this wrong? It would be great if there was a way to override that
 
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