A website about the 1987 Corvette C4 that was converted to an EV by Motorola in 1994.
Who made this car?
In the 90's Motorola had a team building EV engines. One engine was the EX-12, of which the team made 3. One was installed in a Chevy S-10, one was installed in an Indy race car (also called the EX-12) and one was instaled in a Corvette C4.
The EX-12 race car is featured on evalbum.com and it went on to win several races. The Corvette was built mostly to demonstrate that the engine could drive a street car.
How did you end up with it?
After the EX-12 project ended the car was taken to APCity, a salvage yard in IL. In 2022 it was discovered and reported on by Kevin Williams, who was reporting for The Drive.
I read his article and in 2023 I bought the car and imported it to the UK for restoration.
What batteries is the car using?
The car has always been powered by 14 Lead Acid Leisure Batteries. When the car arrived in the UK it contained a mixture of Marathon M12V90 batteries and some similar looking test batteries.
The CTEK could not save this one!
Today it's running 14 recently purchased Sonnenschein gf12050v batteries.
How fast can it go?
I don't know, I've barely driven it 3 ft! The pack shows ~186V when fully charged and I am told that the software will limit the current draw to 800A. Which would suggest it could get to nearly 200 bhp. In practice these batteries are not supposed to have such a large amount of current drawn from them. The team that originally built the car tell me that on the orignal batteries could run at 800A but would become unusable after only a few charge cycles.
I'm not planning to push the car in any way until it has a modern battery upgrade.
How far can it go?
Again I don't know. Until it's licenced for road use this is not possible to test. With the current batteries I'm not expecting more than around 20 miles.
How do you charge it?
Originally the car had several off-board chargers, unfortunately none of them came with the car. Instead I've been using this 3.3kW charger from Summit Power. It is now mounted inside the car:
Based on the datasheet for the batteries and some nakpin math, I think it will take over 12 hours for this charger to charge the batteries from flat.
Does it run?
The motor turned on 13th April 2024. It only ran for a moment before smoke started coming out of the power distribution box. After a lot of investigation and a few wrong turns this was tracked down to the pre-charge resistor burning out. Since then this has been replaced along with quite a few rotten wires and other compoents.
The car has been partially reassembled and can drive under it's own power.
It's important to mention that the car is still being re-assembled. In this video it could drive fowards and backwards, but the steering wheel was not connected!
Is it road legal?
After conversion, the car was registered in IL as an electric vehicle. I have the title and registration documents. To be registered in the UK it must pass an MOT, which today it would fail. The UK has a number of regulations which Corvette's of this era do not comply with. For example, rear indicators are required to be amber in the UK, whereas the Corvette's are red. Now that the car is running again, the other problems are relatively straightforward to address. I'm hoping to have it registered before the end of 2024.
What's the goal of the restoration?
Once the car has passsed MOT in the UK and recieved a license plate, the plan is to devise a way to upgrade the battery. The EX-12 motor is significantly more powerful than the current batteries. A modern pack should allow the Ex-12 to deliver more bhp than the original L98 5.7L TPI engine as well as being lighter and providing significantly longer range (and faster charging).