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jokeitch

Crazy plan: A Tesla and chevy Volt powered EV hotrod S30

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So uh, this is early planning stages, i'm just going to lay the plan out and fish for feedback from you guys on feasibility, suggestions, thoughts, etc.

 

I've wanted to do a classic car EV conversion for a very long time, and soon i'll be in a financial position to do so.

The plan is to get a classic, drive it and enjoy it for about a year, get used to the platform's quirks/specs/aftermarket/maintenance, THEN jump into the conversion.

As for which classic? it's still a bit of a tossup between an S30 and a C3 corvette since the styling of both really speak to me. They both have strengths and weaknesses in my eyes, both the cars themselves and as EV swap candidates

 

The EV drivetrain will be a tesla model 3 performance rear motor placed where the differential lives. No driveshaft (but probably an armored tube for coolant+power lines), no taking up space in the engine bay, just half shafts and probably extra welded in mount points for the model 3 motor casing's subframe mounts. 400 wheel horse power is very reasonable, if not a little less. This thing will haul ass, to the point where really wide tires with fenders are probably a necessity to keep from just skidding everywhere.

 

The batteries will be chevy volt modules, 2.5 battery packs worth to get right to 40kw of capacity. This should get me like 150 miles of range on a good day, although i may drop that to 32kw for 120 miles of range but less weight and cost and packaging complexity. Volt packs are low energy density but high power density. Not much range, but you can THRASH them for power and they won't voltage sag, which you can sort of equate to heat soak. Also they have built in coolant pipes and they're super friendly to DIY hacking.

 

Battery placement will be in the engine bay, in the area where the gas tank was, possibly one or two in the empty transmission tunnel, and maybe one or two in the rear luggage compartment. I have a somewhat ambitious wish of making the battery (not the motor) install largely reversible by making use of the original motor and transmission mount points to make a battery "cage". This is because i imagine WAY better batteries will be available from junkyards in as little as 5 years and i want to not be "Stuck" with one kind of battery geometry forever, so it pays to plan for obsolescence.

 

CCS quick charging is a must. being able to 30 minute fast charge is basically a requirement for usability when you're under 150 miles of range. More ambitious plans include putting a chevy Volt engine on a trailer with a shorty exhaust and tiny gas tank with an armored cable to provide a continuous 30-ish-kw while cruising on the highway, giving me a muuuuch longer cruising range.

 

for perspective, the electric conversion parts alone will probably total 15 grand if not more. yikes!

 

Thing is, i don't know much about the Z (hence this post), so here's some questions:

  1. How strong is the rear subframe? can it handle 400hp going through a differential or do high horsepower v8 swaps have to beef it up a lot, and if so how?\
  2. How spacious is the area around the diff? is it right up against the body or sitting kinda low? the model 3 drive unit isn't THAT big but it's definitely bigger than a standard diff, and weighs a good 200-300 lbs
  3. Would you say the engine bay is pretty spacious? Or kind of cramped compared to most other cars? 
  4. Same question for where the gas tank is mounted up. Really limited space or pretty roomy?
  5. Do they handle really well and not-sloppy stock? Or do they need a ton of suspension work to feel more "modern" (like how the corvette c3 needs newly made most everything and a rebuilt steering box or it's a boat)
  6. would an extra 500lbs to the curb weight completely kill the car? or can some stiffer suspension keep it feeling tight with that much extra heft?
  7. how simple are the electricals/vacuum systems? If the engine is literally missing, how much of the car will be screwed up? Beyond the obvious things of the A/C compressor, power steering pump, and brake booster. Like if the door locks will need to be converted to electric, etc.
  8. what's a better starting point, a bone stock s30 that was well kept, or an SBC swap that was done well and not hacky? I'd prefer the SBC unless there's some fundamental discrepancies that'll make an ev conversion harder

 

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1) It doesn't have a rear subframe.

2) Google "240z dimensions" there's a drawing that comes up as the very first picture.

3) Have you ever seen a 240z before? You can fit a V12 in there.

4) It'll fit a gas tank.

5) They won't feel modern, ever.

6) The battery pack alone weighs 1200 lbs. You're gonna be adding more then 500 lbs to the car.

7) ....what? Power steering pump? it's a 240z.

8) Don't ruin a clean one.

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Posted (edited)

oh, for some reason i thought some of the 240's had a power steering option but maybe that was on later 260s and 280s. Or maybe it was never ever a thing. Shows how much (little) i know.
edit: nope, literally never a thing since it's so dang light. A lot of ev conversions switch to electric power steering because it sucks way less power than a hydraulic system, and that seems to be the more popular option for the Z so uh, yay i think

 

that dimensions graph i believe you're referring to is really rough, i was fishing for anecdotes along the lines of "oh god no it's squished up in there" or "yeah it's practically in it's own little roomy cave back there". No rear subframe complicates things, means i'll need to weld up a cradle with mount points to match the 3's drive unit.

 

the Volt packs are about 400lbs each, which includes all the extra insulation chevy uses. So 800 for 2x roughly. Also remember all the fuel lines, transmission, drive shaft, diff, exhaust, and everything engine related except the accessories are going away. Even the stock radiator can go since a small intercooler is more than enough cooling capacity for the motor and batteries. that's gotta be like 700 pounds worth of weight gone considering the engine alone is ~500

 

looking at the gas tank's uneven geometry and location, i could fit one larger module (each Volt pack has and some charge controller bits back there, probably

 

also sorry if this comes off as shooting down information, I do really appreciate the response, i'm just adding more context 

Edited by jokeitch

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It has a frame structure, but not a removable rear sub frame. With the spare wheel well and gas tank removed you have quite a bit of room back there.

 

There are some 3d models of the chassis floating around. 

 

Modern sport suspension and steering is a pretty different animal. You can get pretty sporty handling out of these cars, but what they have going for them is light weight. If you add 1000lbs up front in batteries you are going to really be stressed to find suspension to compensate.

 

This has been done a few times. You may have to do some digging, I know a couple locals that have done the ZX's I know someone on here did an S30.

 

Might want to consider a tube chassis with a body on top ala "B is for Build" where he did a tube chassis and welded the body to it. 

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ah, i should clarify that by "modern handling" i mean not really wallowy and sketchy feeling. Of course, i'm using classic american cars as a comparison point, where "oh god what is the suspension doing i'm going to die" is the baseline, whereas on the Z it didn't have that problem from the get go. So perhaps just some basic stuff will get it where it feels right for me.

 

Trying to keep the engine bay added weight to be comparable to an SBC swap, so like, 650lbs worth of batteries. Beefier springs will need to be up front to compensate of course. one big module can go in the gas tank area and maybe another few behind the driver's seat as a luggage compartment partition of sorts. 

 

I looked around for EV ZXs but they're almost all old style setups with forklift motors and lead acid batteries that have awful power and no range. Being able to utilize all of the engine bay because the motor isn't there makes for a fundamentally different animal of a layout. 

 

Tube frame, maybe, seems like possibly overkill. In that case it'd either be gutting a clean s30 or getting a really janky shell i need to build back up into a car, which i cannot drive for a year in the mean time :(

 

i guess this is one major point in favor of the C3, it has a boxy frame underneath to start with. It's a little floppy stock but some gusset bracing makes it pretty stiff.

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Posted (edited)
17 hours ago, Ironhead said:

Are you the same guy who posted on r/Datsun a while back about doing a Prius powered S30?

 

Nope. That sounds like it'd have awful range and power, to be honest, but I guess the parts are exceptionally cheap by comparison

Edited by jokeitch

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On 6/28/2019 at 5:07 PM, jokeitch said:

I have a somewhat ambitious wish of making the battery (not the motor) install largely reversible by making use of the original motor and transmission mount points to make a battery "cage". This is because i imagine WAY better batteries will be available from junkyards in as little as 5 years and i want to not be "Stuck" with one kind of battery geometry forever, so it pays to plan for obsolescence.

You should probably think of it as a one off, you will have to do some innovative modifications to tie that stump puller rear end into the unibody.  A 280z that has had a badly done V8 great cause it should be cheap, 240's are just too expensive now.

The body was only designed for about 200hp so will have to beef it up, electric power steering is easy and light.  Big big project, will take lots of dedication and probably more than a few years. I hope you do it, would love to watch.

 

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i think its only a matter of time before tesla swaps are more common. i would suggest using a s130 just cause they are cheaper to start and who cares if you cut one of them up and never finish it. im a s130 guy but even i wouldnt mind seeing one cut up and not finished. i would be super excited to see one finished also..i didnt exactly read the whole thing but i saw something mentioned about power steering. alot of s130's came with pwr steering, not all though..

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6 hours ago, G-Tech said:

i think its only a matter of time before tesla swaps are more common. i would suggest using a s130 just cause they are cheaper to start and who cares if you cut one of them up and never finish it. im a s130 guy but even i wouldnt mind seeing one cut up and not finished. i would be super excited to see one finished also..i didnt exactly read the whole thing but i saw something mentioned about power steering. alot of s130's came with pwr steering, not all though..

 

The S130 doesn't grab me quite as much.

Thing about a huge, expensive project like this is i want to start with a car i actually truly like instead of "eh, gotta use this one because x y z reasons", so i'm not dropping 15-20 grand and 6 months to a year of time on a car i settled on.

 Also, curb weight started in the 2900 range on those. Part of the reason the Z is appealing over the Vette is the low starting weight, since weight is the enemy for an EV in general

 

19 hours ago, Ryanotown22 said:

But why do you want to do this?

 

Future of hot rodding, lots of fun, cool challenge, etc.

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Posted (edited)
On 6/29/2019 at 3:40 PM, grannyknot said:

You should probably think of it as a one off, you will have to do some innovative modifications to tie that stump puller rear end into the unibody.  A 280z that has had a badly done V8 great cause it should be cheap, 240's are just too expensive now.

The body was only designed for about 200hp so will have to beef it up, electric power steering is easy and light.  Big big project, will take lots of dedication and probably more than a few years. I hope you do it, would love to watch.

will it be that bad? I'm fine with some degree of fab to get the model 3 rear end to fit in there. It definitely won't be reversible back there, the motor's just too big, but i want to minimize body cutting...
On the upside the gas tank's right behind the diff it seems, and that's mutable so i might end up using the gas tank area for part of the motor and also bracing. 

poking around, looks like some folks make fancy custom diff frames when they're pushing down lots of power.

but yeah, the pure weight of the motor could be the biggest problem, it's a 300lb nugget replacing a 80 pound-ish thing

Edited by jokeitch

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There are a few people who have put s13/s14 rear subframes in the s30's.  I'm sure dimensions are not even close but it may give you an idea of what is involved in putting a subframe in the back of a z.  You may just have to cut the chassis off in the back & weld in some square tubing to mount it too.

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On 7/2/2019 at 12:39 AM, caperix said:

There are a few people who have put s13/s14 rear subframes in the s30's.  I'm sure dimensions are not even close but it may give you an idea of what is involved in putting a subframe in the back of a z.  You may just have to cut the chassis off in the back & weld in some square tubing to mount it too.

 

holy shitballs

 

Image result for s14 subframe into s30

 

Image result for s14 subframe into s30

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Oldish thread, but I wanted to share some of my preliminary research on this topic.

 

This swap seems pretty feasible if you have a wrecked Tesla available to you, or if you have about $16-20k for Tesla parts alone. It's not easy or cheap, but it's definitely not impossible. Some obstacles will include converting the rear end to accept the Tesla rear subframe. Several people have put in Nissan S13 and S14 rear subframes on their S30s, so a Tesla rear subframe is not impossible. See my attached pictures to see examples of a Model X and Model 3 subframe with motor and complete rear suspension. You'll pay in the neighborhood of $4k for a Model S/Model X rear assembly, and maybe $10k for a Model 3 rear assembly. With those rear assemblies, you are reducing your moving parts count by lots. Tesla drivetrain omits the following:

  • engine
  • transmission
  • driveshaft
  • differential
  • alternator
  • water pump and coolant system
  • pulley driven air con
  • timing belts / chains
  • ignition systems with spark plugs
  • fuel pumps and fuel regulation
  • fuel tank / cell
  • exhausts / mufflers / emissions control devices

The Model 3 has a very advanced modular battery array compared to the S and X. In the 3, Tesla situates them all in a row below the floor and they each have integrated circuitry. The S30's floor isn't long enough to place a stock Tesla Model 3 array in. If you have half a million dollars, maybe you can buy a Tesla Roadster for parts 😅. If you removed modules from this array, you'd still also have to raise your S30's floor by at least 4 inches. Or. you can reconfigure the array and have the modules line your engine bay and the hatch area. There's also the transmission tunnel which you'll no longer need, which you can widen at the rear to facilitate the storage of several battery modules. Currently, complete battery arrays from wrecked Model 3s are in the $10k range. Check out Jack Rickard's video of a Model 3 teardown: 

 

Some people are creating their own LiIon battery arrays, but the Model 3 is truly next generation stuff with great longevity and energy density Lastly, you'll need "engine management" ... it's territory I haven't researched heavily, but a good start would be checking out EVTV Motor Verks and EV Controls, neither of which I have any experience or affiliation with.

 

Basically, you can put pretty much anything in a Datsun but getting it to work (reliably and safely) is another story. I have two Tesla PowerWalls for the house, but I definitely don't have $10k for a battery array for the Datsun, so I'm just roll with the S14 subframe that I already have. I know EV swaps are inevitabie in the near future, so I might save the Tesla dual motor swap for my Land Cruiser. 

 

I know some people ask "why do this?" Once people have ironed out all of the wrinkles, good battery tech comes down in price and charging times are reduced (graphene batteries and supercapacitors, perhaps), the performance potential and overall simplicity make pretty compelling reasons. Also, if you generate your own electricity, even better.

 

 

Model 3.jpg

Model X.jpg

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Telsa swapped Porsche is my next build I will attempt (If I can find the money).  https://www.zelectricmotors.com/

 

They don't use the model 3 batteries.  They all model S battery packs.  https://www.evwest.com/catalog/product_info.php?cPath=4&products_id=463&osCsid=do45arn6gds71gq6vo893ikdk5

 

You can buy pretty much everything you need to swap them into a VW or Porsche.  Pretty neat stuff.  

 

Telsa Motor

https://www.evwest.com/catalog/product_info.php?cPath=8&products_id=476&osCsid=do45arn6gds71gq6vo893ikdk5

 

 

 

 

 

 

Edited by DuffyMahoney

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I've thought about the drivetrain from the RWD/AWD Lexus GS450h and LS600hL. We have a LS600hL and the power from the electric motor assisting the V8 5.0L is really nice, but I don't know how to feel about a CVT transmission in the Datsun. I suppose there won't be any gear shifting with a pure EV anyways.

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