# 1975ish Corvette conversion



## Loa (Apr 5, 2015)

*1975ish Corvette conversion [on pause]*

Hello, 

I'm in the beginning stages of planning (hope to start the build next Spring) for this project. The 1975ish Corvettes, because of (relatively) weak ICE engines, are pretty easy to get for cheap and they weigh around 3500lbs/1600kg stock.

My plan is to get an EV car roughly equivalent in terms of power to the ICE engine (approx 200hp/150KWh), and ultimately get a 80miles/130km range. The minimum range I could start with would be 60miles/95km. 

Here's my plan so far: 
*-Motor:* leaning towards 11". 

*-Batteries:* first option are used tesla packs. The only drawback is that I will need to buy 7-8 to get decent power out of the 11" motor. And even used, this will be expensive. But from what I've gathered, these packs are the best power/weight/price combo. (Please correct me if I'm wrong.)

*-Speed Control:* no precise model yet, but a 1000W module should be enough. 

*-Battery management system/charger:* no idea. 

*-Battery cooling system:* no idea. 

Im still in the research stage, haven't bought anything yet. So if you want to make suggestions (either on battery type, component spec, etc...), you're more than welcome. 

Thanks. 

P.S. I plan on documenting the build here as I go along, but don't expect much until Spring (which, where I live, begins in May!  )

Update: After making a parts list and checking all the prices (including Canadian conversion, and taxes), the project ended up being too expensive for the range I needed. As of now it's on pause, but when more tesla packs and perhaps even Bolt packs hit the used markets, I may consider it again. Thanks for the help!


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## gte718p (Jul 30, 2009)

C3 corvettes are fun. I did a conventional restoration on a '78. I loved that car.

They start kind of heavy, but there is a lot of weight that can be taken out of them.

Someone on here was working on a C3 conversion. An 11" should be plenty for the performance you want. Though your range and performance goals clash unless you plan to spend a ton on batteries.

I look forward to it.


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## Old.DSMer (May 18, 2012)

Hey Loa, take a look at my build. Similar weight, similar goals, similar expectations. I went CALB CA series, but your Tesla plans will be great. Don't discount Volt packs.

Your biggest problem might be finding space for the batteries. I really like your plans and am looking forward to seeing more!


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## Loa (Apr 5, 2015)

Thanks for the encouragements. 

I do plan to spend a ton on batteries: as I understand it it's the most expensive part of the build.  I'm expecting (based on recent ebay prices) to spend about 10K US$ on the packs. 

I plan on putting the batteries behind the seats. It's been a while since I've worked on a C3 Vette, but I'm sure there's enough room there. I'm also considering the front of the engine bay, where the radiator sits, for a couple of packs if possible. Ideally I'd fit 8 in the back and have room for more later one if I need more range. 

The first thing I'm going to be doing when I get the Vette is to take the body off and work on the battery placement and holder!

Old.DSMer, I haven't found a lot of info on the Volt packs, especially their availability for such projects. I'm open to the idea though. 

Loa


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## Old.DSMer (May 18, 2012)

Your battery budget is reasonable. And there are a few threads in here discussing Volt batteries purchased from wreckers. If I was doing my conversion now, I would be giving them a serious look!


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## gte718p (Jul 30, 2009)

Loa said:


> Thanks for the encouragements.
> 
> I do plan to spend a ton on batteries: as I understand it it's the most expensive part of the build.  I'm expecting (based on recent ebay prices) to spend about 10K US$ on the packs.
> 
> ...


The tank under the dash is probably not as big as you think. It is a good place to stick batteries, but you will also want to stick some upfront to help with weight balance. You can gain a little more if you are willing to do some fiberglass work and cut the the two compartments where the battery lives out and make one big space under the rear deck.

I would not put the batteries all the way forward. Makes the car feel less sporty by increasing the moment of inertia on turns. An 11" motor is tiny compared to a 350 or 420 motor. There is plenty of room for batteries along the frame rails and above the motor.


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## Frank (Dec 6, 2008)

I'd be looking at Volt packs too, tons of info out there you, just have to zero-in on it. With the frame-off (you'll probably need to make some repairs, think windshield area, trailing arm support, etc.) you might see a way to keep batteries down low and as centralized as possible. It's been 10 years since I sold mine but I wonder if you run direct drive if it wouldn't open up a lot of space for a pack?









(This isn't mine BTW, just a pic I snagged somewhere. The limit is your imagination!)


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## Duncan (Dec 8, 2008)

Hi Frank
A Corvette is a bit heavy for a direct drive 11 inch DC
That's what I'm running in the Device - which is great, but at 800Kg It's a bit lighter than a Vette


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## jwiger (Oct 18, 2014)

A few folks have noticed higher HP out of the 9" motors due to the higher RPM. Combine that with a decent gear box, and you will never have a lugging issue. Unless you want high top speed, then you simply need more motor. There is an El Camino build using two 9" motors you may be interested in seeing. He is pretty far along after doing a frame off resto. 

Sent from my STV100-1 using Tapatalk


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## Loa (Apr 5, 2015)

Hello James, 

I'm not at all sure how to compare the +/- of all the different motors available. With ICE engines, the torque/hp curves give you a very good idea of what the engine can do, but I don't know what to look for in electric motors. 

Also, I'm focusing on the netgain motors as I see them in many conversions, but I don't know much about other companies. 

Loa


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## piotrsko (Dec 9, 2007)

Quick and dirty: 750 watts is generally equal to 1hp. You wnant 400 hp? Then you need 300,000 watts which in my case at 200 volts is 1500 amps. Hmmm. Bit much for my soliton and battery pack. 15C on the batteries.

Otoh, the ice engine only makes 400 hp at floored conditions, at maximum rpm.

Idle uses perhaps 10 hp, cruising the city streets uses perhaps 30 hp, freeway uses 50 to 100.

Nice thing about electric motors is they keep making hp as you add power up until the point that you start melting stuff.

Simplistic as heck rules of thumb.


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## dtbaker (Jan 5, 2008)

you have a couple challenges with high torque DC. max rpm is low, meaning you HAVE to have a beefy transmission with at least high/low. The dragsters use planetary setups, but you're talking $5k or so for the transmission.

The available 'off the shelf' transmission adaptors from CanEV don't include any big block chevvy or Ford transmissions last I checked. So, you've got to plan design time and expense for a custom adaptor.

- the big 11" have lower rpm ceiling, meaning you NEED a big beefy transmission to get both accell from zero and a decent cruising speed top end.

- tandem 9" may be a higher output, and some controllers like the Zilla can 'shift' the motors from parallel to series voltage.

you should poke around in the gallery for some of the high output builds people started and see what their solutions were. There has been at least one corvette, and a Hot Rod in the 400ft-# torque range.


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