Hello all,

I'm a long time lurker here, and I've posted a few times, but I'm starting this thread to discuss the upgrade I'm doing to my 74 bumblebee LE.

I converted the car to electric drive starting in 1995. I purchased the car in 1994 with the intention of putting in a chevy v8 or something, but after looking at what that would take I opted to put in an electric drive train. The car was sitting in a field with weeds all around and no interior, engine, transmission or anything. It took a few years to just get the car restored before I could put in the electric drive. I got the car on the road as an electric in 1997. It has been a fantastic car for commuting and it is a lot of fun to drive, but with all the lead in the car it was a bit heavy.

I decided last year that I was going to upgrade the car to lithium power which will remove about 700lbs of battery and give me more power and more range at the same time. I purchased a gearbox (BorgWarner 31-03) that is the same as a Tesla Roadster, and I got a Siemens induction motor and inverter that will give me almost as much power as the Roadster. I should end up with a little less weight than the Roadster which should allow me to have similar performance numbers...assuming I can get enough grip from the tires.

In order to fit this motor and gearbox under the hood, I'm going to have to remove the firewall between the trunk and the motor bay. The gearbox sits between the axles (obviously) and the motor will sit above it (hence the space time conflict with the firewall). This is not a problem since I've seen posts with this firewall and trunk floor removed and then triangulating by putting a bar between the strut towers and then two more from the towers down to the rear trans cross bar in the trunk. This part of the build is all pretty clear in my mind. The connection between the strut towers works perfect as an upper mounting point for the motor and gearbox. Existing motor and trans mounting locations work for the lower support.

The area where I have a question is with regard to the gearbox location. In order to put the gearbox and electric motor in the car, it installs like a transverse motor in a FWD vehicle. The gearbox is mounted slightly to the driver side of the vehicle and the motor is to the passenger side. So instead of the existing 901 getting installed exactly in the center between the two wheels, I'll have to mount the eGearDrive about 5" toward the driver side of the car comparatively, and then I'll have to put in an intermediate half shaft on the passenger side to allow for the articulating portion of the axles to both be equal length (about 5" shorter than stock). Anyhow, this is my question, and one that I thought I'd ask for help here first before heading to a drive shaft shop to get opinions. Will the suspension work well with 5" shorter drive axles. It means probably steeper angles as the suspension articulates, but I think it should work. I just don't have any experience in this area and I'm going to have to get some help with this decision before I start cutting the trunk apart to install all of it. If it does not look like it is going to work I'll have to come up with a plan "B".

I'll post some pictures in a later post, but I wanted to get the question about the drive shafts out there since I need that answered.

Thanks,
Michael

If it is a true LE, please don't cut it up. Find another tub.

EMPI makes various axle lengths in a 33 spline count. A 914/944/Bus CV can go to around 20 degrees of angle before destruction. Pacific Customs will sell individual axle lengths so you don't have to buy pairs.

It is a true LE, and it was headed for the recycle yard when I revived it nearly 20 years ago. It has been electric drive for nearly half its life now, and certainly has more road years as electric since I don't know how long it sat unused as a gas car without the motor and trans.

Anyhow, I hope the fact that I'm keeping it on the road will make up for the loss of the firewall in your mind.

Thanks for the link to Pacific Customs. I'll send them an email and see if they can quote building some custom drive lines for me. There is also a shop here in Sacramento I'm going to see if they want to quote custom drive lines.

20 degrees is quite a bit. I'll see if I can get an estimate on the angles it will create with the 5" shorter axle.

http://www.pacificcustoms.com/porsche-930-...moly-axles.html

Axles will be around $100 each through these guys.

That's funny. I bought my 914 with the intention of converting it to electric. I was NOT a car guy at the time. After driving it, I decided it was too much fun and am doing a 914/6 conversion instead!

But I still want to do an electric conversion someday...

I've seen similar numbers on other CV joints in my research since you posted this, so it does make sense. Given that the stock axles are 20.25" long and you can have up to a 20 degree angle, that provides 6.93" of wheel travel in each direction. Almost 14" of total travel. Clearly we are not taxing the stock joints. Now if I shorten the axle to 15" then a 20 degree angle will allow for 5.13" of travel in each direction. 10" of total travel. I'm fairly certain that the wheel cannot travel more than 5" in either direction, but I'm going to lift the car and see how far down they travel just to be sure.

Does anyone have any specifications for rear suspension wheel travel on the 914? A quick google did not turn up anything, but I'll keep looking.

OR, use the rear shock insert range of motion length and adjust per the difference in suspension mounting point of rear axle vs shock mount. Your suspension shouldn't travel outside the range the shock insert will let it.

Some race 914s use a nylon webbing strap to limit the overall suspension drop: these cars are tightly sprung and low and do it so springs don't shift in their seats when frequent lifting to change wheels occurs. So, that's not a fix for driving, but food for thought.

GOTS TO ASK - how much $$$ for the new set-up???

I too originally bought my 914 for an EV, but am having too much fun trying to expire my 1.7 TIV while saving $$$. The kits I've seen for the conversion are $8k-12k total, w $1k-3k for motors and $2k-3k for lead acid batteries. It's been a few years since I looked up prices...BUT I recently saw a guy selling "rebuilt" Prius batteries!!

Good luck! I'll be watching for updates

I had about $10k into the original conversion parts back in the 90's. That did not include all the expenses that went into the restoration of the car before I put in the electric drivetrain. I had to purchase a 901 tranny and a complete interior for the car as well as countless small parts that were missing, paint, body, suspension, drivelines, etc. I really have no idea how much I spent on this car, but I did not choose to work on this car because it was going to be a big money maker for me, I chose to work on it because it is such a fun project car and a blast to drive. Once I got it going on the road I was hooked.

It started to get a little boring so that is why I decided to spice the car back up again. I'm probably going to spend much more on this upgrade than I did on the original conversion. Already spent $9k on lithium batteries and $5k on the motor, gearbox and inverter. Probably gonna be another $1k on just getting the drive-lines connected. But the fun part of the project is all the "free" labor that goes into it. The car will never pay for itself...actually I get payed back handsomely the day I get it back on the road and feel the pride of accomplishment. It felt great the first time and I'm betting it will feel good this second time as well.

With regard to the limiting. I installed the AutoAtlanta economy suspension kit 20 years ago and I don't remember any limiting components. I'm sure there must be something, but I've not taken a close look. When I head out to the garage tomorrow to work on the car I'll take a look.

Like to see some Picts, even before u change to the new lithium battery.

Dave

Hey, Stockton. My car spent many years in Stockton. It was a Stockton ICE and then electric from 1997-2000 and 2005-2012. I moved to Florida from early 2000 to late 2004. Then we moved to Sacramento in early 2012. Did you catch the article about my car in the local paper "The Record"?

About a year or so after I got the car running, a reporter from the newspaper contacted me. A coworker of mine called the paper and they came out to do a story. About 9 months later the article showed up in the paper. The reporter had absolutely zero technical background and was not interested in anything technical about the car which was the complete opposite of my interest when building the car. I was not sure how well he would do writing an article about this car, but in the end I think it turned out ok. It’s definitely a human interest piece and not a technical piece.



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Originally published Monday, October 11, 1999
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Electric avenue
By Christopher Lewis
Record Staff Writer

Rule No. 1 in the as-yet-unwritten guide to driving an electric-powered car: Watch out for pedestrians in parking lots.

If you think they’re oblivious now to cars backing out of parking spaces, just wait until they can’t hear you.

Pulling out of his driveway one afternoon, Michael Palmer of Stockton demonstrated how he’s spooked a few innocent bystanders. He turned the key in his 1974 Porsche 914 and … nothing but dead silence.

Instead of vroom-vrooming to life, the car sounded like it had a dead battery. Actually, the little bugger had 21 juiced-up batteries rarin’ to go.

Like a kid working on a school science project, Palmer, 31, kept his electrical creation a secret during three years of garage tinkering. Friends and co-workers were positively electrified last month when he unveiled the Porsche during his daily commute.

“They thought I was nuts,” Palmer said. “But the reaction so far has been all positive.”

He thought the revamped car might anger Porsche purists. But the 500-amp motor, which ran effortlessly at 250 amps (about 70 mph) during a quick test spin on the Crosstown Freeway, has almost as much muscle as the original 75-horsepower engine. All for about 4 cents a mile.

“If this was a company project, he’d have a bonus that would support you and me,” said co-worker Bob Reynolds of Franrica Food Tech in Stockton, where Palmer works as an automation engineer on food-processing equipment.

“I was totally amazed,” Reynolds said. “The only noise it made was the tires on the pavement.”

Palmer’s Porsche didn’t have an engine when he bought it, either. He paid less than $500 for the beat-up frame lounging in Brent Berkebile’s front yard in west Stockton, looking like junked leftovers from a teenage gang’s Saturday night strip show.

Palmer had her towed home and dressed her up. He painted the exterior black and yellow and installed a fiberglass convertible roof.

“(Brent) kept calling me up — ‘Do you want these engine parts?’ ” Palmer said, chuckling mischievously.

Berkebile, who works at Martini’s Auto-
motive, said Palmer showed up at his house unannounced last month.

“I was eating dinner and I didn’t hear anyone (drive) up,” Berkebile said. “I thought he was just going to put a fuel-injected, 2-liter Porsche (engine) in it. I looked underneath and I said, ‘Kind of quiet, isn’t it?’ ”

He was impressed with the car’s performance. “It has a lot of pickup,” Berkebile said.

Perhaps the biggest perk is the running list of headaches Palmer can do — actually does — without: no more tuneups, valve adjustments, oil changes, radiator leaks, busted fan belts … (insert your own “no more” here). Replacing the batteries every five to six years for a total of about $1,000 is still a bargain compared to regular car maintenance, he said.

And smog checks? Puh-leeze. That’s, like, so 20th century.

The state Department of Motor Vehicles was impressed — they gave Palmer’s ride a clean bill of health and new registration.

“They just flipped out,” he said.

Palmer may blow off smog checks, but his electric car has a few reality checks. The motor doesn’t have quite the same kick going up hills, in part because the batteries pack an extra 300 to 400 pounds.

The main roadblock is the limited range — the car can go a maximum of about 100 miles before recharging. A full recharge takes about eight to 10 hours. But Palmer carries an extension cord in the trunk so he can conveniently plug in to a standard 110-volt outlet wherever.

The car runs on 20 six-volt traction batteries more familiar on putting greens than roadways. Golf carts typically run on four to five such

batteries. A smaller battery powers the radio, headlights and blinkers.

Besides the speedometer, the only instruments Palmer relies on now are the palm-sized volt and amp meters.

Several local government agencies employ electric vehicles, but they’re struggling to dent the mass market because of the high cost. The cities of Lodi and Stockton, which are exploring grants to lease electric cars, might get a charge out of Palmer’s Porsche. He researched electric cars on the Internet and purchased $5,000 worth of parts from Bay Area and Arizona companies.

The Porsche isn’t Palmer’s first project. He worked on a solar-powered car while he was a student at California Polytechnic State University. And his mountain get-away is a 1968 Ford Bronco he restored after college with a digital dashboard and computer-controlled engine.

He’s got wheels for each of the four decades he’s lived in — the Bronco, the Porsche, a 1987 Toyota Corolla (possibly his next electric venture) and a 1991 Corvette.

But the Porsche is the jaw-dropper when Palmer rolls to a stop at intersections.

“People just turn their heads and look at me funny,” Palmer said. “They are curious. Most of them have never seen an electric car. They want to know all about it.”

Thanks for sharing that info

It's about what I figured on costs to go w the newer batteries and motor. Not cheap, but comparable or cheaper than some other engine conversions done. If/when you get Tesla-like performance numbers it will make the EV a more respected option for 914 projects.

If you can mock-up the motor/tans install and post pictures I'm sure more folks could offer advice. Why not offset the whole thing, to make equal length axles, and then balance weight distribution w offset battery placement?

Have fun

Yesterday I removed the motor and transmission. I still have much more to remove before I do a mini restoration on the engine compartment and give it a quick coat of new paint.

Started work on the temporary support between the rear strut towers. I'll have to figure exactly where to place the permanent support once I test fit the new motor and gearbox.

For comparison, here is the new motor and gearbox temporarily connected together getting ready for a test fit into the car. The level that I have sitting on top should be just about where the bar will be going between the strut towers. Looks like it is going to be a nice fit. I'm getting excited about the possibilities here.

You are looking at the driver side of the gearbox, and the motor sits on the passenger side of the vehicle.

So the CV+axle attaches where that big red circle is?
Would be good if you could lay that whole thing flat instead of mounting it upright!

Yes, the red plastic plug is the driver side output. I've gone around a dozen times and this is the best solution. If I lay it forward, then the motor and gearbox fill much of the engine bay and I lose a lot of space I need for the fuel tank (batteries). Otherwise I'd have to put batteries in the front and rear trunks and I think putting them all in the engine bay will keep the car balanced best. I'm using the gas tank area for the charger and some other electronics, and so I'll have the front trunk usable as well as what is left of the rear trunk, and I'm hoping to still have the rear large enough to stow the top.

The other option was to turn it around and have the motor on the driver side and behind the axles, but that would make the gearbox turn backward and the lubrication is designed in such a way that the turning gears "pump" the oil. Its really only designed for light loads in the reverse direction.

That left me with the option of putting the motor above the gearbox and hence the need to move the firewall back.

Very nice! I applaud the use of the Siemens motor - what controller are you going to use? What battery pack voltage? Which battery are you going to use?

Oh my, so many questions.

Reason I ask is that I have converted my 914 to electric, but went a slightly different route: 108 CALB60Ah, 100kw BLDC motor and controller (from a chinese company - don't do that), and stock transmission. Next round will up the battery pack and use a real AC motor (MUCH lighter and smaller), and use a direct drive transaxle.

So it looks like you've done what I shoulda done. Do you have specs posted anywhere?

Cheers, Peter

I'm still looking for some information about suspension travel. My question in post #6 was not answered. How much suspension travel does a 914 have?

My car is sitting without any motor or transmission, and just for the sake of documenting some numbers I found that the distance from the edge of the fender to the center of the wheel is about 14" when sitting like this. When I jack up the car and let the wheel "hang" it extends to 15". When I loaded all my batteries into the car is dropped to 12". I'll have another 250lbs to add with the motor and gearbox, so I assume it will drop another 0.5 inches. to put it at about 11.5 inches. That makes the downward travel about 3.5 inches. How much upward travel can I expect. Is there a suspension wiki somewhere? I have not found anything so far regarding how much travel to expect on the rear suspension (nor the front).

I'm not exactly sure that I understand your needs here but I'll give it a shot. It appears that you have a rough idea of the travel from full droop to full compression. Most people would do this measurement without the coil spring installed.

But for practical planning of a fully built car, realize that you can control the travel by factors such as spring rate, spring length, adjustable spring perch, and probably several others that I haven't thought of. For example my race car has 350 lb/in springs and has a real world working travel of about 1 1/2 inches. This would not be comfortable on the street but I believe that 3 inch travel could be livable. My car would go into coil bind at about 3 inches compression from static weight on wheels. You definitely don't want to go to the bump stop or to coil bind as this would effectively set your spring rate to infinity and would not be good for you or car. Perhaps others with street driven cars can add to this discussion. Good luck with your project.
Steve

Well, not quite. I have full droop to car sitting static. I'm missing the full compression and that is my question. How much will it compress. I suppose it does depend on the springs, but I thought I could find some information on the full travel on a stock car. I guess I could remove the springs and measure the full travel distance, but I thought asking the question here would get me a quick answer.

Are there bump stops? I guess my car did not have them when I purchased and if I had them, I guess I could easily measure it. Measuring distance to coil bind may be a bit more difficult. Perhaps I could just purchase the bump stops and then I'd know the answer to my question.

I'm not sure what CV you are using. There is an off road version of the 930 CV. It's called a "Non Plunging" CV. Is has a range of motion of 40°. It needs to be used with a plunging axle. The EMPI style axles are a plunging type with 3" of spline length. This allows the axle to slide in the CV.

I plan on upgrading to this type of CV since I still hear clicking from my standard 930 CV's. I already have the axles. I don't know of any other style of non plunging CV without going to a tripod style CV. Tripods are used on many FWD vehicles to allow for steering.

Michael, as a rough ball-park/extreme figure could you just measure the distance between the top of the tire and the inner wheel well while loaded as described? This won't tell you how much your shocks/springs will compress, but it will give you an idea of the limit of travel. Just thinkin out loud.

Yes there are bump stops and they are located in the shock. They are hard rubber-like things slotted and installed on the shock rod and are typically removable and replaceable. On a Koni shock you remove the bump stop and then fully compress and rotate the shock to change the setting from stiff to soft or vice versa. Bump stops are the last bit of protection for the shock when undergoing a hard full compression and are intended to prevent metal on metal contact.
If you look with a flashlight up in the top of your rear shocks you should see the bump stop. I use a bent over coat hanger to retrieve the bump stop from mine when I need to remove or replace them.

Some cars have bump stops mounted to the body or frame and suspension members but to my knowledge the 914 does not use this design on any of the model years.

You can get a rough idea of the distance to coil bind by simply measuring the distance between two coils and multiplying by the number of coil gaps. Normally your suspension will get to the bump stop prior to coil bind as this is a safer transition than directly to coil bind.

In your case it may be best to build the car to completion and with the car on its wheels measure the amount of distance that you have until coil bind and try to get the distance to the bump stop. Measure this with a stiff piece of wire that runs from the bottom of the exposed shock rod to the bottom of the bump stop. If either is inadequate, go to a higher spring rate and/or longer spring. You may have to convert to a shock with an adjustable bottom spring perch. If you are expecting a large amount of suspension travel, then the post about CV joint deflection is important and you must take steps to keep the CV's within their design deflection limits. Cars are systems and one change often leads to a cascade of impacts.

I really like to see the electric projects, surely is the future of cars and just love the
sure quickness potentially up for grabs !!!!!! Your project looks great and I'm sure you will revise things because its just so new and an ever changing technology.
I hope to do one as well but am just not tech savvy enough to tackle a project like this.

Ok, I forgot about that and you cant see them once installed. I installed them almost 20 years ago, and since then it has just been driven...not any work except battery watering and replacement since then.

And now I have my answer...at least close enough to an answer. I was able to take a coat hanger and with the car wheels hanging at full droop again, I got an estimate by pushing the coat hanger end against the bump stop and then marking the other end at the top of the shock. It was 6.75 inches (+/- 0.25 or so). Assuming this number is good, with a total travel length of 6.75 and the car sitting 3.5 inches up from there, that means I have another 3 inches of compression before hitting the stops. This means I'm sitting about right in the middle and I'm also not worried about drive angles with my shortened shafts. Things are looking good. Not much other progress on the car since I got sick right after Christmas. So much for taking a week off of work to work on the car. Back to weekends and evenings in the new year.

Wow, neat projects. I'm curious re the use of the gearbox, do you use all gears, and how are shifts accomplished ??

I am thinking of doing one of these conversions on the near future. What's the Avwrage cost on parts?

Hey Paul
This thread has some information and some links.

http://www.914world.com/bbs2/index.php?sho...=157923&hl=

Thanks

For those that remember Otmar, another electric/914 guy - he is now putting a Tesla Model S drivetrain into his stretched Vanagon (don't know if this has been linked before):

Electric Vanagon

With the DC conversion, the max RPM is about 5000, so shifting is not unlike the stock motor. The DC system had much less power and torque than the motor I'm installing now, so the transmission was necessary. Actually the car ran very much like a stock 914. It was quite a bit heavier but I had about the same horsepower and a bit more torque than the stock motor, but it (torque curve) was flat from 0rpm to 3000 or 4000 where it began to taper off. The new motor has much more torque and is capable of 10,000 rpm, so I can get away with a single speed gearbox. I'd prefer 2 speed, but the single speed gearbox that Tesla used in the Roadster is very efficient and robust, so I am going to be using this same gearbox. Downside is that I'll be limited to 95mph at 10,000 rpm.

As far as conversion costs, the cost varies wildly. If you purchase old forklift equipment used and install used batteries, I've heard of people doing it for under $3000, I've also heard of conversions over $50,000 in components. I'm going to be in the $25,000 ballpark, and my first conversion on this car was in the $10-$15k range. (neither include vehicle restoration costs...which I'm discovering more every day as I remove parts...no surprise to anyone here I'm sure)

Discussion of conversions and cost should be moved to the linked thread above. PM me if you post there, and I'll join the conversation over in that thread. I'd like to keep this thread about my conversion specifically.

Thanks and sorry for the hijack.

Michael,
Cool project. I wanted to build a electric car until researching and finding out the cost...pretty pricey.

If u need any help on it let me know, i work in Sacramento area and would like to learn more.

Dave

Another waste of a 914

Fixed that for ya.