# Investigating converting BMW 318i



## ebne0018 (Jun 10, 2008)

I have the opportunity to buy a 1993 BMW 318i 4 door sedan and I am considering converting it to electric. I have looked on google and found some people converting older BMW's, but not specifically this family of 3 series.

I am interested in what everyone's thoughts are about converting this car.

Here are pros/cons I have come up with:

pros:
1. manual tranmission
2. Engine still functions so I could sell the motor to offset the cost
3. Lots of parts available for this car
4. Weight distribution in BMW's are great
5. This car was designed to take BMW's inline 6 motor so the engine bay has lots of room 
6. BMW engines are very heavy, so removing the engine will save more weight than removing an engine from a similar sized vehicle
7. No traction control/ABS
8. Suspension/brakes were designed for the larger engine, so adding batteries will not kill the car
9. Car is in good shape
10. AC does not work so no loss their

Cons:
1. 2800 pound weight
2. Power steering
3. no easy to buy interface plate available
4. no easy to but battery brackets



I work about 4 miles from my home and I live in Minneapolis, so range isn't critical. It would be great to get 60-80 miles to a charge, but 40 miles would work. 
Freeway speeds would be nice, but not necessary.

All input is encouraged and thanks in advance


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## Thaniel (May 25, 2008)

Personally I think it is a great idea. You find some others that have done it here: http://www.evalbum.com/type/BMW

pros:
1. manual tranmission
Yes this is a plus. 4 door cars with manuals are hard to come by
2. Engine still functions so I could sell the motor to offset the cost
I wouldn't count on much money from the motor. Being a 4 cyl it is not highly sought after. Even if it were a 6 cyl it would need low miles to be worth much. On a different E36 project I did I sold the motor, trans (auto) driveshaft, exahaust, computer all for $100 and felt lucky just to get rid of it.
3. Lots of parts available for this car
Yes yes. Stiffer springs or even coil overs to adjust ride height after the added weight of batteries will be no problem.
4. Weight distribution in BMW's are great
Yes but it's all going to change so the starting point is really moot.
5. This car was designed to take BMW's inline 6 motor so the engine bay has lots of room 
It does have a decent sized engine bay. A V-8 would even fit (wink)
6. BMW engines are very heavy, so removing the engine will save more weight than removing an engine from a similar sized vehicle
I suppose. THey do have an iron block but being a 318 your motor is small
7. No traction control/ABS
Really? my 93 has ABS. I deflinately want ABS. It doesn't care anything about what motor is in the car. I know this for a fact. My daily driver with an engine swap has had a chance to work the ABS on slippery days.
8. Suspension/brakes were designed for the larger engine, so adding batteries will not kill the car
As long as you don't exceede the gross vehicle weight rating for any car the added weight will not be a problem
9. Car is in good shape
 That's a plus.
10. AC does not work so no loss there
I guess.

Cons:
1. 2800 pound weight
Are you sure? I thought E36s were more around 3200. Then again I am always looking at 325's
2. Power steering
This is not a con. PS can be kept or if you don't want it convert to a manual rack. Check a BMW racing forum for how.
3. no easy to buy interface plate available
True. If you want a bolt on kit better go with a more popular car to swap.
4. no easy to but battery brackets
Same as above. 

Personally I'd use a 325i to start as the diff is stronger and the high torque of the electric motor could kill the 318 diff pretty easy. However the diff can be swapped on a 318 for a larger diff if it is an issue.

I like the handling of the 3 series BMW's. My drive is 9 miles each way and full of curvey roads. So I'm going to design for 25 mile range but still get a good 0-60 accel if possible. 

Thaniel.



ebne0018 said:


> I have the opportunity to buy a 1993 BMW 318i 4 door sedan and I am considering converting it to electric. I have looked on google and found some people converting older BMW's, but not specifically this family of 3 series.
> 
> I am interested in what everyone's thoughts are about converting this car.
> 
> ...


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## etischer (Jun 16, 2008)

I thought that would be a good candidate too. I say go for it. I got started on a passat conversion for the same reasons you listed. The engine is cast iron in my car, should free up a ton of weight. 

Im thinking about having a second small electric motor to run accessories like AC, PS and alternator. There are cars with electric ac compressors and electric power steering pumps. I think the Subaru XT and toyota MR2 had electric units? 

Is the 318 a hatchback? 2800 pounds is considered light these days.


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## karlos (Jun 30, 2008)

Thanks for your interesting observations guys, after a year or two of thinkingabout it I also came to the conclusion that the BWW 318i might be the one of the better candidates for the same reasons you have come up with.
I actually bought a Toyota Celica for a conversion but the thing has very little traction (really bad in the wet) and having had 3 of the 3 series and loving the handling, I really like the possibilities.
After looking I also saw that there were no adapters to be had off the shelf but Electric Automotive http://www.electroauto.com/index.html seem pretty keen and able to get parts made for a new model. They like the client to supply the gearbox to measure which is a bit hard for me to do as I'm in NZ. Are any of you guys close to them (Felton CA) and able to give them the gearbox to work with? Of course it means using their motors and controllers of which I like the AC option which is air cooled for the system they use.
Let me know how you are going!
Karlos


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## DVR (Apr 10, 2008)

karlos said:


> Thanks for your interesting observations guys, after a year or two of thinkingabout it I also came to the conclusion that the BWW 318i might be the one of the better candidates for the same reasons you have come up with.
> I actually bought a Toyota Celica for a conversion but the thing has very little traction (really bad in the wet) and having had 3 of the 3 series and loving the handling, I really like the possibilities.
> After looking I also saw that there were no adapters to be had off the shelf but Electric Automotive http://www.electroauto.com/index.html seem pretty keen and able to get parts made for a new model. They like the client to supply the gearbox to measure which is a bit hard for me to do as I'm in NZ. Are any of you guys close to them (Felton CA) and able to give them the gearbox to work with? Of course it means using their motors and controllers of which I like the AC option which is air cooled for the system they use.
> Let me know how you are going!
> Karlos


Karlos, any machine shop should be able to do it for you as KIWIEV found out, but it will cost $
As a machinist, I can tell you that it is a straight forward job and most of the price is in the working out. The alluminium will only cost about $60 aus. steel less.
Hint. Work it all out yourself, make a drawing and take it to a machine shop. That will just about halve the price straight up.
Or, find a mechanic who's into swapping out motors for drag cars or Dune Buggies or such. They make adapters all the time and shouldn't be to daunted to do it for you especially if you don't want the clutch.

I've got a brother in law who's into buggies and he can do an adapter plate to put a nissan on a VW box in about an hour with a Gas AXE!!!
Rough as guts but they work and he races them!


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## TelnetManta (Jun 5, 2008)

What did you ever decide about the 318? I have a 318 that I'm about to begin converting.

Ben in SC


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## karlos (Jun 30, 2008)

*


TelnetManta said:



What did you ever decide about the 318? I have a 318 that I'm about to begin converting.

Ben in SC

Click to expand...

*Hi Ben, thats great you are about to start. What motor,controller, batteries etc have you decided to use?
The 318 is still maybe my preferred option but I'm also seriously looking at a Porsche 924, a pre power steering model (less complications and lower power consumption) Also the Porsche has the transmission at the rear. Anyone thank a 924 is a bad selection? 
So far my preference is to use Electro Automotive AC equipment, more pricey then DC but more efficient (less batteries required = less cost and makes up for extra AC cost), less voltage drop, regen etc. If I felt I would keep the vehicle a long time I'm tempted to go for the Siemens motor and Evisol Controller which I understand has a built in DC DC converter (if built in does it the extra price make up for not having to buy a separate converter?) to run normal car things. 
Still, safety wise it would be good to have the 318 in a model that has the airbags etc. Does your 318 have airbags and is it a compact model?
Someone mentioned somewhere they wanted a car without ABS, would that just be for the extra room under the hood or is there another reason?
Does anyone know of the quietest vacuum pump to use for the brakes?
Cheers
Karlos in Akl NZ (anyone else in Auckland building an EV?)


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