The Tesla Model S/X drive unit places the motor behind the axle, and that's where the fuel tank is. This could be a packaging challenge, depending on the orientation of the battery modules. The overall plan seems workable, but a realistic look at how everything would go together would be required.
Rate my build plan (c3 corvette)
5
Location: San francisco, CA
Budget: Like 15k for the donor car, and hopefully less than 20k for all the conversion parts and any labor costs.
Donor car: 1975 c3 corvette. They're cheap, easy to convert the bumpers back to the wonderful 68-72 chrome bumper design, and have some decent safety equipment upgrades over the early cars. A clean 1975 is like 15k, a clean 1970 is 25k or more, YIKES
also, maybe some race car flair to it, need big rear tires to hold all that torque eh?
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Motor: Tesla model S P85 large rear drive unit OR Tesla model 3 performance rear drive unit. The entire tesla rear subframe and all the suspension components, fabricating mounts so it bolts onto the c3 ladder frame. This could be relatively easy or the hardest, most expensive part of the entire project. The motor 3 motor is more efficient when not under heavy load, and FAR FAR better cooling capacity BUT nobody supports their firmware yet and it isn't clear how many years it'll be until the T-1C supports it.
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Battery: 34kw of chevy volt batteries. I'd like Gen2 but the Gen1s are half the price and only slightly lower capacity. Some in the engine bay with a battery enclosure to make it look like a V8 because yummy under hood candy, like ICON's derelict mercury EV did. the rest of the batteries go where the gas tank used to be, which may or may not hang lower and thus cause the full size spire tire sling to have to go away. Volt batteries have excellent high performance because of almost no voltage sag. They're also cheap, work very reliably, have a nice log-like form factor, and have built in excellent battery cooling. I'm hoping for 80+ miles of range
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Cooling: unsure yet, but the water pump and electrically controller diverter valve out of a tesla. chevy volt batteries and the tesla motors have built in cooling systems so no need to screw around making chill plates.
Controller: EV Controls T-1C, pretty close to turn-key, i'd buy it from EV west specifically so i can lean on them for tech support and general info. This controller's already been used in a few tesla motor/chevy volt battery builds
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Contactor: unsure
Power steering: I really want to keep hydraulic power steering, electric pump driven. It's wasteful but it feels so much better than electric power steering. EV West makes a belt fed pump but i'll probably re-use the one that came with the car.
A/C: MVP might omit this since i live in a SF and A/C is kinda unnecessary
Charger: Not sure how to get there, but i absolutely want to shoot for a 50kw charger which interfaces with CCS. With such a short range this feels like a heavy requirement for this to be driveable. There's some noises about CCS charging for DIY builds but this might be a wait and see, hopefully this becomes a mature thing soon (within a year). For 50kw, maybe just stack 5 of those 10kw tesla chargers...?
Safety: Haven't researched much but i would really like switchable fuses between every 72 volts or so, so at any given moment during assembly or maintenance, if i make an oopsie, i only get shocked with 72v before a fuse cuts it. Also, inertial fuses so in a crash, everything is isolated from everything else. Also, a first responder safety line, mimicking tesla's implementation with a BRIGHT RED WIRE right under the hood with a really obvious label on it.
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Timeline: purchase the c3 within a few months, spend about a year maintaining it, adding quality of life upgrades, more deeply researching the platform, more deeply researching the feasibility of my componentry and fabrication. HOPEFULLY buy most of the drivetrain bits in advance and make sure the entire thing works on a bench, THEN start converting in fall of 2020 and be done some point before fall of 2021
So, what am i missing, what bad assumptions or assessments am i making, etc
Budget: Like 15k for the donor car, and hopefully less than 20k for all the conversion parts and any labor costs.
Donor car: 1975 c3 corvette. They're cheap, easy to convert the bumpers back to the wonderful 68-72 chrome bumper design, and have some decent safety equipment upgrades over the early cars. A clean 1975 is like 15k, a clean 1970 is 25k or more, YIKES
also, maybe some race car flair to it, need big rear tires to hold all that torque eh?
Motor: Tesla model S P85 large rear drive unit OR Tesla model 3 performance rear drive unit. The entire tesla rear subframe and all the suspension components, fabricating mounts so it bolts onto the c3 ladder frame. This could be relatively easy or the hardest, most expensive part of the entire project. The motor 3 motor is more efficient when not under heavy load, and FAR FAR better cooling capacity BUT nobody supports their firmware yet and it isn't clear how many years it'll be until the T-1C supports it.
Battery: 34kw of chevy volt batteries. I'd like Gen2 but the Gen1s are half the price and only slightly lower capacity. Some in the engine bay with a battery enclosure to make it look like a V8 because yummy under hood candy, like ICON's derelict mercury EV did. the rest of the batteries go where the gas tank used to be, which may or may not hang lower and thus cause the full size spire tire sling to have to go away. Volt batteries have excellent high performance because of almost no voltage sag. They're also cheap, work very reliably, have a nice log-like form factor, and have built in excellent battery cooling. I'm hoping for 80+ miles of range
Cooling: unsure yet, but the water pump and electrically controller diverter valve out of a tesla. chevy volt batteries and the tesla motors have built in cooling systems so no need to screw around making chill plates.
Controller: EV Controls T-1C, pretty close to turn-key, i'd buy it from EV west specifically so i can lean on them for tech support and general info. This controller's already been used in a few tesla motor/chevy volt battery builds
Contactor: unsure
Power steering: I really want to keep hydraulic power steering, electric pump driven. It's wasteful but it feels so much better than electric power steering. EV West makes a belt fed pump but i'll probably re-use the one that came with the car.
A/C: MVP might omit this since i live in a SF and A/C is kinda unnecessary
Charger: Not sure how to get there, but i absolutely want to shoot for a 50kw charger which interfaces with CCS. With such a short range this feels like a heavy requirement for this to be driveable. There's some noises about CCS charging for DIY builds but this might be a wait and see, hopefully this becomes a mature thing soon (within a year). For 50kw, maybe just stack 5 of those 10kw tesla chargers...?
Safety: Haven't researched much but i would really like switchable fuses between every 72 volts or so, so at any given moment during assembly or maintenance, if i make an oopsie, i only get shocked with 72v before a fuse cuts it. Also, inertial fuses so in a crash, everything is isolated from everything else. Also, a first responder safety line, mimicking tesla's implementation with a BRIGHT RED WIRE right under the hood with a really obvious label on it.
Timeline: purchase the c3 within a few months, spend about a year maintaining it, adding quality of life upgrades, more deeply researching the platform, more deeply researching the feasibility of my componentry and fabrication. HOPEFULLY buy most of the drivetrain bits in advance and make sure the entire thing works on a bench, THEN start converting in fall of 2020 and be done some point before fall of 2021
So, what am i missing, what bad assumptions or assessments am i making, etc
1 - 20 of 81 Posts
Yes, DECAlink completely replaces the Corvette's rear suspension with a sound multi-link suspension that does not use the axle shafts. It uses two longitudinal links per side, similar to the stock suspension in that respect, for compatibility with the C3 structure; as a result, it doesn't need an extensive subframe. If I were upgrading a C3 and wanting to keep the structure close to stock, I think this would be a good choice... but the probability that I would ever spend tens of thousands of dollars to upgrade a C3 is zero.... i think this detroit speed kit solves the axle shafts as suspension members problem
https://www.detroitspeed.com/1963-1...3-82-corvette-stock-differential-041740-group
....for $8,800
My guess is that crossmember is there primarily for the final drive and leaf spring carrier, so it may not need to be replaced at all.unfortunately the giant can impacts that crossmember bit, so that'll have to be cut off and a new crossmember welded up
https://drive.google.com/file/d/1WOz5oaK8srJ2t_ot8tWBb4p5Ygk_Get1/view?usp=sharing
another benefit of a model 3 subframe setup: the motor's quite a bit smaller
The other obvious way to address motor bulk is to use the Tesla Model S/X small drive unit. While never used by Tesla as the only motor for a vehicle (it's only in AWD variants), and obviously less powerful than the large drive unit, it might still provide better performance than most stock C3s.
The Model 3 motor isn't just smaller - it's mounted ahead of the axle line, changing what it might run into. The Model 3 subframe is also differently shaped, due to the different suspension.
I see the name "corvolt" in an image filename. "Volt" made me think of "Bolt" - you could use the 150 kW Chevrolet Bolt motor instead of a Tesla, and not get anywhere near that crossmember.
Right, you would need either boost the Bolt or Tesla small motor output, or build a two-motor all-wheel-drive C3 (with either brand of drive units).
And regardless of the motor or even the battery, "CorVolt" is a pretty good name for a Corvette EV.
1 - 20 of 81 Posts
