Robin W.

The best place for info is on my blog. http://electricporsche.ca but I'll keep updating this as well.

I took it for a short drive on a ~50v battery pack (doesn't do much for my 288v motor) however I did want to test shifting.
The 1-2 shift is ok, however 2-3 is just like using the clutch (with the rpms that I could manage at 42v under load anyways)
Do you guys know how much noise the transmission/torque tube/brakes make?!?!?! (when the motor doesn't make any noise) It's not alarming but it's a bit annoying. I think I may have to ADD sound deadening to this car, then it should be whisper quiet.

The car drives well, I only had about 100A at 42v under load so that's a very boring 4.5hp to the wheels (give or take) however I did manage a 3rd gear run to 40km/h. It feels a lot more powerful though, since it's 74ft-lbs of torque off the line, tapering to about 15-20ft-lbs as I run out of voltage.

I can't wait till I can get the proper batteries, 310v and 1000A will be a lot more fun.

AScholtes

Sounds good. I like to hear about stuff like this (not my cup of tea to do personally, but I do like the technology involved) as it shows how innovative people are... Being a tech junky, I love to follow along and learn as much as I can about what the DIYers come up with compared to the OEM's and all their fancy engineers... pfft, amateurs! LOL

St3mpy

I read about not needing a clutch. Quick question though: If you ever do decide to go with a racing clutch, could you install it in the rear inside the transaxle's bellhousing?

Questiong 2: Could you run an automatic transmission? I don't have any experience with autos on the 944, but i would imagine the torque converter has to be in the rear, correct?

Robin W.

The clutch is in the front, it would be more work than it's worth to relocate it to the rear. If for whatever reason I need to reinstall the clutch I still have all the parts and it would go back in the front where it was. I don't know anything about the auto, but an automatic transmission could be used with no problem. My motor controller has built in logic to "idle" the motor at whatever rpm you specify so it would run just like an automatic. Usually the shift points have to be adjusted, or the use of a "tiptronic" style of shifting to let the driver make the best use of the electric motor. Since the auto is only a 3 speed it might actually work well with the increased torque of the electric motor. I don't know how strong the auto is though, I have the 5 speed out of a turbo in my car, I'm about to order the Lindsey racing ultra mount transmission mount so hopefully that will help handle the extra torque at low rpms without breaking cv's.

Does anyone have direct experience with the Lindsey Ultramount?
I could fab my own solid mount, but since the electric motor doesn't make much noise the transmission/torque tube is already the loudest part of the car, I don't want it to get louder.

AScholtes

I would try the fill method on the stock mount before ordering another mount... it gives the same benefit from what I have been reading.... PM me if you need some links..

Robin W.

I saw your links in another thread, lots of good reading, including the "pan hard" type bar to locate the transmission, however I would start with the main mount.
I do have a tube of window weld waiting here (bought two, only used one to do my hatch) The other thing that interested me was the urethane fill method around the stock mount. I'd rather get it done right the first time instead of correcting after breaking something else. I'm probably going to launch the car hard once in awhile with 300+ ft-lbs available from 0rpm it might be hard on the mount/cv/axles etc.
Since I ditched the clutch everything that the motor can put out is going to make it to the transmission with no extra support who knows what would happen. Even a V8 can't make the kind of torque I'll have off the line (without a 3000rpm launch that is)

AScholtes

The urethane fill would likely be the best bet over the window weld. With no engine noise, hard mounting the trans is going to be noisy....

Robin W.

Well I haven't done any updates for awhile so I guess it's about time. I've been driving the car a bit lately (still a small battery pack, so I'm limited to 25km) but it's fun to drive and very quiet. I'm just about to put the heating system in, 3kw of water heater to pump through the stock heater core. It has a lot of torque and it's comfortable starting in 2nd (turbo transmission) it will also start in 3rd with no problem, but with slower acceleration. As soon as I have heat and more battery I'll be driving it to work daily. Right now I have about 90lbs of LiFePO4 cells powering the car so it's still pretty light. With the new cells it should come in just under the stock curb weight when finished.

Does anyone know how the fuel economy gauge works? I know there is a sensor input to the main harness and it also uses rpm? or speed? Any info would be great, I would like to re-use it as a "fuel economy" gauge to represent current draw. At the moment I'm using the oil pressure gauge to show battery current and it's handy but needs work, I'm using the temp gauge to represent voltage, but I would like to switch things around so the temp gauge shows controller temp, oil pressure is battery voltage and fuel economy is battery current. That way the only "weird" one would be oil pressure. The speedo/tach work just fine along with 12v battery voltage. I also have some digital gauges below the stereo, but they don't exactly match the interior so for daily driving I would like to turn them off but still have a rough idea of what's going on from the stock gauges.

Van

I believe the fuel economy gauge is operated by vacuum - when the throttle body is closed, more vacuum is created then when it's wide open throttle. The higher the vacuum, the less fuel you're using... thus the more MPG. The lower the vacuum, the closer you are to WOT - the lower the MPG.

On a turbo, the boost gauge is obviously intake pressure (both vacuum and positive pressure). It's sensed by the KLR computer which then sends an electric signal to the gauge in the dash. I'm not sure how the NA senses or calculates it, though.

Glad to hear you're using the car! How long does it take to charge?

Robin W.

thanks for the info, perhaps I'll just have to hook it up and see what it does. I'm sure the gauge itself wants a 0-5v or 0-12v signal but I'm curious about the interaction with the tach or speed signal.

At the moment the car takes overnight to charge, but that's only because I have a single 120v 15A line in the garage right now, so I have to share it with lights, tools etc. I'm going to look at getting a 240v 100A line to the garage which when I'm completely done with the charger would let me charge from empty in 1 hour. Or top up from my commute to work in 15 minutes, giving me 100km range and a 15min to 1 hour fill up. (that's all the range I needed, more range costs $$, weight and space)

The fastest I could charge based on the batteries limits would be 10 minutes, however I would need to hook up to a small power station. 480v 3 phase at 350-400A would get me close but that's not gonna happen any time soon.

Van

That's gotta generate some heat!!

86 951 Driver

Very cool to hear. How do you shift with no clutch?

Robin W.

Just like shifting with a clutch but don't press the clutch. The rotational mass of the motors armature is a fraction of an engines rotating mass and back pressure. The syncro's do a really good job at matching the speed and you can actually watch the rpms increase as you down shift. There are no racing shifts here though, it probably takes 1/2 a second to let the syncro's adapt and it just falls into gear. I have noticed issues if I'm not completely stopped it's hard to get it in first, but since I don't normally use first anyways it's not a big deal. My typical driving around town is 2nd and 3rd gear so there isn't much shifting anyways, plus I can start in 3rd gear just fine.

steel968

So i've been looking at this more seriously lately as an alternative to my gas guzzling commute. I see you have heat, but will you have A/C? I live in south texas and i'm unsure how you would drive the a/c. What do you think?
I looked at EVTV products and I like what they have. I was thinking about the Netgain Warp 11 Motor, what od you think?

drift a 944

Saw this in May 2013 up at Road Atlanta. Had to take a few quick pics. Crazy stuff!