Duane Ball's Porsche Carrera GTS 904 Project

This week, we take a look at one of our viewer's builds. This is a very interesting one to us.

If you recall, we bought an electric Spyder, done very similarly to our Part Duh Speedster. The similarity was not entirely accidental. Duane Ball was doing the Spyder in Albany New York at the same time I was focused on Part Duh. It was his first conversion and we kibitzed almost daily.

I drove Duh last night. I had been driving the Mini Cooper every day. But we added a brake transducer this week and are trying to get it working with the Rhinehart Motion Systems controller. They have some new firmware incorporating the brake potentiometer concept, and frankly we are having severe difficulties with it. It's thrown the whole car off.

Fortunately, the weather has turned spring so I've driven our just completed Redux the past few days. It's very nice. It's quite powerful. And it's going to the dynomometer today to find out just what we did do with the Soliton 1 and Netgain Warp 9.

So last night I took a cruze in the ivory Duh.

I have to tell you, we will never do a better electric car than this. It is just perfectly balanced and "right". No issues. No things to be worked off. The gear ratios are perfect. The motor is perfectly matched to the system. We will no doubt update to the new Curtis controller. And we could always use more instrumentation. But this car just drives "right". I can shift entirely without the clutch. It just feels good.

In any event, when Duane got done with the Spyder, it worked quite well. But he went into decline because he and Scott weren't meeting every weekend to work on the car. It drove fine. He just missed "the project."

He started talking about a new Chuck Beck replica - The Porsche 904. This was a 1964 era race car. I knew little of it. They only made 108 of them. Porsche kind of confused the naming of it because this was the period when they wanted to bring out the 901 but for trademark issues with another car maker, they could not. So it became the 901, and the 904 became the Porsche Carrera GTS.

It was quite successful as a racecar. Like the Spyder, there weren't very many of them.

According to Chuck Beck, the 904 was the greatest car Porsche ever built. Street legal and race ready, and the first fiberglass Porsche.

So Duane wanted to convert one of those. So he wanted to get his money back out of the Spyder and invest in a 904 where just the ROLLER was going to cost $53,000.

So we bought the Spyder.

Actually we are going to do some work on the Spyder. Airkweld has a set of rotors/hubs that are very lightweight aluminum. They're proud of them, but it would knock 100 lbs off the car. Duane had put Porsche 911 wheels on the Spyder using some adapters that make the wheels stick out a bit. So he had to raise the front end so it would steer. Etc. etc.

Bottom line is it's not quite right from our perspective. So we'll put on some of these lightweight rotors - we use regen for braking anyway. And have them done in a different bolt pattern so we can go to a 9 or 10 lb wheel as well with some Michelin Energy savers.

We're going to dyno the car, and then change the controller to the new 650 Amp Curtis upgrade, and dyno it again.

Should be interesting.

But in this week's video, we give a little history of the Carrera GTS and then include a video report from Duane on the 904 conversion. They have received the roller and are back happily at work on a new project to convert it to electric drive. Again, we're kind of kibbitzing on components and I've steered him this time to again kind of what we're working on with the Escalade - a Netgain 11 inch with Soliton1 controller and 50+ CALB 180Ah cells.

It has the potential to make a fantastic, very aerodynamic and powerful electric sports car. True, he'll probably have $75G in it when he gets done. But a Tesla Roadster realistically runs twice that. And this one will be every bit as much fun.

We also take a look at a couple of things on the Mini Cooper. We installed a 250 psi 0-5 brake pressure transducer and wired it into the Rhinehart Motion Systems controller. As I said, we struggle with that, but it's a software issue and I'm sure we'll get it worked out.

We also dug out the old Mini gas tank and pulled the innards out of it. Surprise surprise. PLain old fashioned floats and potentiometers report fuel level. The Mini Cooper actually has a most excellentious fuel/trip computer onboard. It calculates MPG in real time and displays remaining range and all sorts of interesting info. Of course, we dont' have any fuel or any gallons.

Or do we? Now that we have a simple resistance sensor input, I could use Ian Hooper's Zeva II fuel gage driver as an input to this computer. Replace gallons with Ah.

Ian doesn't like me very much because he sells a BMS system and I am kind of anathema to all who do so at this point. He has to be a little conflicted though because every time we talk about this little device, he sells out of them immediately.

The Zeva, (Zero Emissions Vehicles of Australia), is actually kind of annoying. The adjustments are mostly in the blind and I get them horribly confused. The unit features a little 5 pin molex and he sends you a mating connector with precisely FIVE pins. If you drop one and lose it, or mangle it putting a wire on one, your ZEVA won't work. Come on Ian. These pins have ZERO cost. Put 10 in the bag. I can't see to do it anyway and if I drop one to the floor there's no way I can ever find it.

And then you have weeks of charging and fully discharging to get the thing calibrated to your pack. But it IS pretty neat. A fuel gage driver, another driver to turn your tachometer into an Ammeter, and finally an alarm for low pack SOC that you can use for ANYTHING. We like this device. It's a pain in the ass. But we love it.

But case in point. Matt Hauber is very anxious to please and cleaned my solder station bench. This is a huge no-no. Yes, I know its a mess, but it's my mess. In doing so, he somehow moved my nice little box with the RC battery, switch, diode, and Zeva kit and spilled it on the bench. Got most of it back together, but now I'm MISSING the little molex connector and the generous allotment of precisely FIVE pins that came with it. So there is no way to use this device at all.

If anyone has the Digikey part number for this connector and pins, I would sure appreciate it. We simply cannot finish this little Mini project without them now.

But the plan is to install the Zeva and use the fuel gage output to drive the input to the fuel computer. I think this will work very well, and we'll have an estimated range remaining, a MPG figure that updates, even though it is a little meaningless until we get used to it. I would predict that will take aobut 10 miles of driving and we'll adjust to it.

So the instrumentation thing continues to be a fascinating area with our cars.

We also talk a little bit about the EVCCON. After two weeks, and a good six months out, we have 32 signed up and 10 cars coming. David Kesler is going to come talk about his J1772 home charging stuff, and Bill Ritchie has joined us as speaker for High Performance Electric Vehicle Systems - that's the powerplant in the Spyder and Speedster Duh. We have Sebastien Bourgois from EVnetics/Rebirth Auto, George Hamstra from Netgain, and Eric Kriss from Kriss motors all speaking.

We also have Dennis Doerffel joining us to do a session on battery chemistry. Dr. Doerffel is one of the pioneers of LIFePo4 prismatic cell testing and the principle behind REAPSystems Battery Management Systems. He also moderates, or even better doesn't moderate the Thundersky discussion group on Yahoo. This is the only online forum I will still participate in occasionally.

I am actually hopping up and down in my seat. I'm enormously excited. I have two big name speakers that we have invited, and they have kind of provisionally accepted. But we're still checking schedules and working out the details and so I CANNOT at this time announce either one of them. EITHER one would blow the lid off this convention in my estimation. And we've got a good shot at getting both.

Since I can't talk about it, let's play guess who? This will be fun and might even be productive. I want you guys to GUESS who I think would be the most important speaker we could get for an Electric Vehicle Conversion Convention. If we could get ANYBODY to come address this meeting of guys who build their own electric cars, who might that be?

The reason this might be interesting, is that who YOU think would be the biggest draw to such a convention might not actually match who I think would be. I may have missed a trick here. We'll have THREE big evening events, Thursday, Friday, and Saturday. If I get both of those I'm working, that still leaves one night open. Of course, I can be the star then. But I'm the star everyday anyway in my own little mind. It would be easy to replace me with somebody good. So if you guess who my "optimum superspeakers" are and guess WRONG, maybe I'll go try to get them. I may have missed somebody.

WHO then, as featured evening speaker at EVCCON, would cause you to WANT to come to this event, beyond any other. If we could get ANYBODY, who would be the ideal headliner.....

This will be fun.

Jack Rickard