924Board.org

[Llamaguy]

About how much would you expect to pay for a 924 or 944 that looks good, like you would want to a daily driver, but that didn't run? as in broken timing belt or other engine trouble, but with a good transmission. I was thinking about building an electric vehicle as a summer project since it would be quite practical for a high school/college student. I was also wondering if anyone else here had converted a Porsche to electric (I had seen a couple electic 924s somewhere on the internet)
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

[Khal]

Dunno what you'd pay for a 924/944 over there... not much if it's broken - especially if it's a timing belt failure, that's apparently a re-build situation. Of course, that might not be important if you don't need the engine! But Fuzzbeaner, who posts here, is doing an electric conversion on his 924. See;

http://www.evproject.com/

So what is it with these electric conversions? I believe it would be a very expensive exercise with ultimately not much benifit. Sure, you get an electric car which is theoretically (and only theoretically, mind you) cheaper to run because you don't have to pay for fuel. But surely the initial costs and maintenance would outweigh any savings fuel-wise... I mean you still have to pay for all the normal consumables and registration, right?
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'80 924 Turbo

[Llamaguy]

simply a fun exercise in electronics
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

[gohim]

Do you mean a 924S or 944, or really a 924 or 944?

A 924 with a broken engine is worth $0-$200. It's a giveaway, unless it has some historical significance, emotional value, or the car is perfect and original, other than the engine.

A 944 or 924S with a broken engine is not worth a whole lot more, since the engine repairs witll often cost more than the car would sell for if running. I would say somehwere between $0-$500 with average body and mechanicals, or up to $1000-$1500 if the body and interior are close to perfect and original.

I would not waster my money on an electrical motor conversion as an experiment. If you want to experiment, you would be better off with a VW Rabbit, Golf, or Jetta. They are lighter, and even cheaper (lots of cheap ones to choose from) than a 924 or 944 would be.

Of course if you paid money for the VW or Porsche, you could recoup some money by selling off the parts that you don't need.

[Llamaguy]

I would prefer a 944 for the looks and possibly oval dash, but a 924 would probably be better b/c of the aerodynamics, less weight, and cheaper
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

[ProudGecko]

My uncle did an electric conversion on a saturn sc a couple years ago. If you have any questions or anything about electric conversions I'm sure he'd be willing to offer his knowledge. Where in Indiana are you located? I too live in Indiana, Lafayette to be exact and my uncle is in Indy
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1988 Porsche 924S
1986 Kawasaki Concurs ZG1000
1984 Mercedes 190D
1973 Honda CB500

[kaffine]

With the electric car conversions do they normally use DC motors or AC motors with an inveter?
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80 924
80 931

The best desciption of an atom boils down to something unknown is doing we don't know what.
Sir Arthur Eddington

[Fuzzbeaner]

With electric conversions it's typical to use a DC motor simply due to price. AC motors are cheaper, but require a helluva AC/DC inverter and a 3 phase motor controller which is usually pretty pricey.

As for use of consumables....well tires yea, everything else is pretty much permenant. If you use a clutch it takes a LOT less stress since you don't have to put it in at stops since there's no stalling, no oil....or gas....and I won't even have a clutch. Remember, one of F. Porsche's earliest projects was an electric car I'm just continuing the legacy! (Chuckle)

As for use of the 944, there's always varying reports about weight, but they definately do get weightier as time goes on. I'll stick to my '77 ultra-light sleek 924!

Anyways, if you have any questions about EVs drop me a line.

-Jeff
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A Ravaged '77 924 (Electric Conversion in Progress)

[Llamaguy]

are you going to use the clutch to shift like a normal car, or are you going to pin it in 2nd?
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport

[ProudGecko]

actually the clutch doesn't take that much less abuse, and it may take more in fact on an EV. It's true that you don't need it to get going from a start but shifting is tricky because the electric motor spins so freely that engaging the clutch will either be very rough or you'll have to slip it alot to get the RPMs down.
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1988 Porsche 924S
1986 Kawasaki Concurs ZG1000
1984 Mercedes 190D
1973 Honda CB500

[CBass]

Unless you reverse the polarity while the clutch is in.
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'81 931 in various states of assembly

[Fuzzbeaner]

I'm going to use the "Pin it in gear method" but the + version.

There's this method of shifting without a clutch. It's called "Power shifting" by those who do it in race situations or what not. It involves tossing it in neutral, and slowly sliiiiiiding into the new gear. I guess it takes 5 seconds or so once you're used to it! I'm intersted to see how well it works! No clutch shifting? What will they think of next....it's like a triptronic tranny, but not at all!

As for normal clutch wear, people say that if you buy a new one they last 200,000 miles + in an EV, but I don't have any first hand experince with it, so I can't tell you.

-Jeff
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A Ravaged '77 924 (Electric Conversion in Progress)

[Khal]

Yeah, you can change gear without using the clutch, I used to do it for fun all the time in my parent's little Ford p.o.s.! You just have to match revs and the gear will slip right in. We generally call it "flat-changing" around here - like on a motorcycle, where you'd upshift without using the clutch while holding the throttle wide open... i.e. accelerating "flat-out". Of course, racing drivers do it too because it speeds up the shift, you don't lose so much momentum. But it's bloody hard to do quickly in a "normal" car without a lot of practice! And if you stuff it up, well, it doesn't do the gearbox a whole lot of good!

You can also just slam the thing into gear without matching revs but you'd wanna have a bloody tough gearbox...
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'80 924 Turbo

[Sleykin]

Depending on how you set up your freewheeling diodes and caps you should be able to closely mimic the speed changes of an IC engine. The freewheeling diodes will also give you engine braking while they try to re-charge the battery. The big catch for me has always been the motor control circuit. AFAIK they still have not come up with a thyristor that will gate off with current flowing. A bank of transistors will get the job done but they are fiddly to balance and toast if you unbalance them. I probably should look around at speed controls again as it has been years since I was involved with it much ... but speed controls for small (2hp) DC motors are still up there in the $$ range. I suppose you could couple up an alternator of sorts to be a feedback for the controler and use that to bias the thirister off?
Just what are ya gonna use to control the places between wide open and off??
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Glenn Neff
Medford, OR
87' 924S

[Fuzzbeaner]

For speed control I'm going to use a PWM (Pulse Wave Modulation) controller. It's sorta like a transistor based SCR controller except it uses a bunch of surface mount MOSFETs. A 5 kohm variable potentiometer is pulled by the old acclerator cable and that potentiometer attaches to an input on the controller. The controller, upon meeting different amounts of resistance, will turn on and off the juice to the motor thousands of times a second, and in that way work to adjust speed. More pedal = closer to 5 kohm number = a larger percentage of time spent in the "On" position.

It's some pretty interesting stuff!

-Jeff
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A Ravaged '77 924 (Electric Conversion in Progress)