1971 Porsche 911T Targa EV Conversion

by Cal
(Buena Vista, Colorado)

A few years ago I picked up an early model 1971 911T Targa.

After stripping her down to the metal, prime, paint, restore the interior, rebuild the transmission & carbs along with some additional engine work, she sounds like a Porsche again. It looks & drives great, but I can tell she is getting tired. Most likely getting close to time for an engine rebuild.

I'm considering an EV conversion instead of the cost of the rebuild. If I understand the procedure correctly, I can still use my transmission. Is this correct? I assume there are various levels or grades of conversion kits.

Where should I begin & what should I expect it to cost?

Hi, Cal -
Congratulations on a great car. I'm quite envious!

First question, yes, you can use the transmission. The question is, is it in the best interest of this particular conversion to do so? The questions you're weighing are cost and convenience vs. excess weight and alternative gearing.

It's cheap and easy to just leave the transmission in and make an adapter plate. But electric motors don't actually NEED transmissions in the same way that gas engines do. Still, for maximum efficiency, some sort of gearing (low and high seems to work fine) really helps. You'll need a bigger motor if you're going to go straight to the drive shaft, according to the consensus of the big electric car conversion brains over at the EV Discussion List.

Next question, are there different grades or levels of conversion? Sure.
You can spend a little and get an EV that runs okay or worse, a never ending project; or you can spend more and get an electric car that makes you happy to be alive. (You seem like a guy in the "B" category, if my crystal ball isn't broken.)

In the new Build Your Own Electric Vehicle, the author gives these numbers for a typical Porsche conversion on p. 3:

"Goes 75 mph, gets 60 miles (or better) on a charge, uses conventional lead-acid batteries and off-the-shelf components, and can be put together by almost anyone.

Its batteries cost about $2200...conversion parts about $5500 to $7000, and it costs $1.25 to recharge."

I'd start with a good conversion manual like the ones I've collected here. Then join your local chapter of the Electric Auto Association.

Best of luck with the Porsche EV project!

Regards,
Lynne

Electric Car Parts and Conversion Costs

by Cal
(Buena Vista, Colorado)

A few years ago I picked up an early model 1971 911 T Targa.

After stripping her down to the metal, prime, paint, restore the interior, rebuild the transmission & carbs along with some additional engine work, she sounds like a Porsche again.

It looks & drives great, but I can tell she is getting tired. Most likely getting close to time for an engine rebuild...

I'm considering an EV conversion instead of the cost of the rebuild.

If I understand the procedure correctly, I can still use my transmission... Is this correct? I assume there are various levels or grades of conversion kits. Where should I begin & what should I expect it to cost?

Hi, Cal -

Allen Antonucci here from Duke's Garage.

Yes you should be able to use your stock transmission.

One thing you'll want to consider is where to put your batteries. You're gonna have 1000 lbs on a 108 volt lead acid system and 450 lbs on lithium ion phosphate.

Cost of batteries alone that we use are around $13,000 and total parts around 30-35k. And if you use lithium ion you'll need a battery management system that is built specifically for your car by a professional shop.

Do not buy plug N play BMS's, they will not be very user friendly and you could have more problems than you started with.

Begin with batteries then motor speed controller "curtis or zilla", AC 9in brushless motor, charger, transmission coupler"adaptor" and wires will get you started on your build.

If you need help finding parts just let us know at Duke's and we'll find a way to help!

- Allen

Duke's Garage is an electric car conversion shop in Westminster, CO which specializes in classic car conversions.