Over the Top Porsche 356 Speedster Redux

We're getting a little carried away here. The addition of Matthew Hauber to the team has given us some mechanical expertise we've just never really had before. And that has given us some opportunities - not on anything particularly magical, but on very ordinary physical things.

They count.

As we became accustomed to Speedster Part Duh, I have to tell you I've grown very fond of these Speedsters. It goes quite beyond the electric car thing, although obviously enmeshed with it. But we did a lot better job on Part Duh and it is just in all ways a more elegant car.

But my first love is the Corvette Tri-coat red Speedster with the Coker whitewalls. It just really feels good to drive.

Reminds me of Obama's campaign speech. "My friends and neighbors, we are privileged to live in the greatest country in the history of the world. With your help, we together CAN change it!"

The original Speedster looks a little.....well....home made. We had a garrish assemblage of TWO strings of 90AH Thundersky cells with cells actually piled on top of cells in the back. Of course, the original Speedster only had TWO useful gears, third and fourth. First and second were just useless. We learned on Duh to change to the 3.44 R&P and suddenly all four gears made sense and looked like someone had done them on purpose.

The wiring kind of goes every which direction. We never did document that TOO well so we're not particularly certain what any one specific wire DOES and some of them no longer do anything.

So we started talking about what we would do to spruce it up. Unfortunately, the heart of the car is the transmission, everything pretty much bolts onto that. And that was the most obvious improvement.

To change it, we have to remove ALL the batteries, the motor, and a lot of the wiring. So we might as well redo the thing. We have a couple of the NEW Netgain motors. They have larger terminals, stouter brushes, and an improved internal fan design. So what sense does it make to remove the motor and put the old one back on with a better one laying on the floor next to the car?

And as long as we're doing that, we DID kind of design a new motor adapter that is lighter and much less bulky than the Canadian EV unit we had used on the first round. Cape Precision Machine now makes them for us, so it's a phone call and a little under $800.

The original Speedster featured a Kelley 1400 amp controller. Kelley showed great promise two years ago with some innovative designs at a very low price. They never quite lived up to their specs, and it is very unlikely we ever saw 1400 amps - in fact, about 550 battery amps was the highest I had seen.

In the meantime, several people have had bad experiences with them - largely by blowing the input caps with clumsy maintenance procedures. But they've developed a bit of a bad reputation fairly or unfairly, and have gradually just faded from the scene. You rarely hear anyone propose a Kelly any more. They're just not a player in this market any longer.

Ours WOULD occasionally and rather mysteriously "kick out" - simply go limp. You can turn the ignition off and back on on this car to reset it and you can do this rolling down the road - so it wasn't a big deal. And it didn't happen often. But it was annoying.

EVnetics is sponsoring our contest and indeed we had already ordered and received two of their Soliton1 controllers for our Escalade project (STILL waiting on Jim Husted). This controller purports to do 340volts and 1000 amps. That's a LOT of power. But the case design is fabulous, it's water cooled, and appears to be a mate for the Netgain Warp 9. What if we tried one of those?

The Curtis 1238 is hard limited to 130 volts and we have been careful to stay more on the 120v side of all of that. But the Soliton1 doesn't have this restriction. We can have as high a voltage as we can string cells. Of course, the Netgain is still a commutator motor with brushes and they arc on higher voltages. The "book" on this motor has always been keep it at 170v or below. With the new brush design, the BRUSH vendor claims it can do 192v with NO arcing. George Hamstra doesn't really want to sign up to that, because he hasn't tested it. But the brush vendor undoubtedly has reason to believe. In any event, I wouldn't exceed 200v with this motor.

I confess I like the CALB cells. It's a close call. The Thundersky Yttrium cells probably DO have a longer life. ANd they are slightly less expensive. But I've always marvelled at the flat discharge curve of the CALB's and have been further impressed at how closely matched the cells are that we receive. I actually had designs on the fairly rare 200 AH cells Thundersky was selling for awhile in EXACTLY the same form factor as their 160AH cells and the CALB 180AH cells. I actually bought 40 of them. That was the James Morrison fiasco and the cells are currently locked in a storage unit in Issaquah Washington while the lawyers wrangle over all that. If it's finally settled, I'll probably get to pay for them AGAIN to actually get them.

So we decided to use CALB 180's for the Speedster.

I've actually designed two aluminum "belly pans" to fit underneath the seats between existing cross members and bolt to them. One pan is about 12.5 inches wide and the other a little over 9 inches. They will run the width of the car. This will allow about 11 cells to lay flat underneath the car in a very advantageous position - very low center of gravity and very central polar moment.

The cost is clearance. We have about an inch and a half recess between the crossmembers. The cells are just under 3 inches thick. And we do have to have some material in the game (0.80 aluminum). But it shouldn't be too bad really.

In Part Duh, we managed 16 CALB 180 cells in the very front of the car, down very low, in a box built by Special Editions. It was a bit of a squeeze as they gimped me a 1/4 inch on the box size. BUt we got them shoehorned in there.

And so I tasked young Hauber and the Brain with devising a similar box for the original Speedster.

They did well. We actually wound up with an aluminum box hanging from the frame that holds the front bumper to the car - very sturdy - with three layers of 0.63 diamond plate interleaved on the bottom. But amazingly, by cutting out a bit more fiberglass and expanding our concept a bit, they manage EIGHTEEN cells instead of sixteen.

THIS week, (after the video was shot) we took on the rear battery boxes. 10 cells on each side of the motor. Again the Hauber/Noto team scored - 11 cells on the small side. We haven't even done the other side yet.

All this starts to come together with 18 in the front, 22 in the back, and 11 underneath for a 51 cell 171v pack of over 30kWh. The original Speedster has actually driven 110 miles on a single charge with essentially 36 x 180. This implies a theoretical max of 155 miles.

Note that's NOT safe range - that's running them OUT. And of course, we have additional weight to consider from the cells themselves. Then too, with additional power available, it would be unlike me not to use some of it occasionally.

But no doubt we wind up with a SAFE range of well OVER 100 miles and potentially 120.

As to acceleration, that remains to be seen. The car will be over 200 lbs heavier. And we've never used a Soliton1 before. IF it can actually do 1000 amps from these 180AH cells, at 171 volts, and let's say that sags to 150, that's a 150 kW power level - not quite TRIPLE what we have in Part Duh and right at 201 horsepower if that number makes more sense to you.

I think we dyno'd 73 HP in this car with the Kelly. And I found the acceleration more than adequate then.

And so I'm really in this for the range and the exercise at squeezing batteries into this car - how far can it be pushed. But I think with the SOliton1 and a 170v pack instead of 120v, we are potentially looking at a beastie in the performance area as well.

Stay with us.

Jack Rickard