Washing the Engine Compartment

Taking advantage of the mild January weather I decided to roll the 320i out and pressure wash the engine compartment (pictures). That will make working on the electric conversion much easier (no grease!). The engine compartment will also need some painting since it will be shown off at car shows or to anyone that is interested in the conversion. I also took this opportunity to clean the grease off the transmission. Though this cleaning process I also got a good look at the engine compartment and what has to been done. The first modification will be to cut out the 12V battery mount. I probably will still have a small 12V battery somewhere but no need for the big cell that was part of the ICE. The old battery mount interferes with the area where the new batteries are going to be mounted. There is a bunch of heat shielding that also has to be removed. I have to decide if I am going to replace the fuse box. The fuse box is in the engine compartment and it has the old-style Bosch fuses - the ones that are not encased in glass. The old-style Bosch fuses are problematic and having the fuse box under the hood leads to corrosion problems. But moving the fuse box to inside the vehicle will require a lot of re-wiring.
Moving the 320i outside the garage is easy because the garage is sloped and so is the driveway. The problem is getting the car back in the garage. There is a 1" lip on the garage floor that is very hard to push the car over. To get around this problem I used an electric winch to pull the car back into the garage. That worked really well. The winch was connected to a rod that I had drilled and lagged into the garage concrete floor. The process of winching the car back into the garage will prove to be handy later in the conversion.

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Weighing the car

I got the Proform vehicle scale setup and was able to measure the 320i weight at each of the four wheels. I will post some pictures in the photo gallery. The total weight after the ICE removal is now 1776 lbs. With a spec curb weight of 2452 lbs that means all the of the removed ICE components weighed 675 lbs. That is just about what I expected for the ICE weight. It is interesting that the driver's side of the vehicle weighs about 40 lbs more in the front and only 5 lbs different between the left and right sides in the back. The front weight difference is probably due to the steering column and associated hardware. The 245 lbs difference between the front and the rear weight distributions now means I have to locate more weight in the front to get a balanced front/rear weight ratio. As I said in the EV Design article, some of the weight in the rear could be moved to the front, like the DC-DC converter.  There also will be more components in the front that will add weight like the transmission.

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Conversion Design

Now the fun starts. The two biggest design problems are the battery boxes and the engine mounts. Batteries will be mounted in the engine bay, under the rear seat and in the trunk.141 batteries in all have to be mounted. The plan is to have 36 batteries mounted in the engine bay, 48 batteries mounted under the rear seat and the balance of 57 batteries mounted in the trunk. The critical aspect of battery placement is balancing the weight in the car. The BMW had nearly a 50/50 weight distribution between the front and rear wheels. The goal of the conversion is to maintain that ratio. The motor and all the other ICE components weighed approximately 600 lbs. The new electric motor and controller weigh about 300 lbs and the batteries weigh a total of 650 lbs. With the other EV components like the charger and the DC-DC converter I expect to add about 450 lbs to the weight of the car. That will put the curb weight around 2950 lbs. The max gross weight of the car is 3500 lbs so there is room for people and storage in the trunk. Check out the EV Design page for more detailed info on the conversion design.
The electric motor mounting will be difficult because the whole drive train has to be assembled and placed in the car to get an accurate measure of where the Siemens motor can be connected to the motor mount points. A spline adapter from EV West will be use to adapt the Siemens motor to the BMW 5-speed transmission. That adapter adds a couple of inches to the drive train length.

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Removing the Internal Combustion Engine

After several tries (all thwarted by snow storms) the 320i was transported to the shop and the EV conversion was started. The car had to be towed because I ran out of gas trying to run the gas tanks down. In addition to the ICE being removed, the exhaust system and gas tanks/fuel system were also removed. The 5-speed transmission was also removed and will be used in the EV conversation. All of the work was done at Henry's Automotive by the mechanic Mark who did a fantastic job. I went with an autoshop for the removal process because I do not have the resouces in my garage for this process. The removal only took a little over 5 hours to complete and went very well with no real issues. This old car has very few connections to the motor which made the removal easy. The gas tanks proved to be the most difficult as the fuel delivery system had to be disassembled and the remainder of fuel had to be pumped out of the tanks. On this BMW there were two fuel tanks, one either side of the drive shaft, directly below the rear seat. That area will be used to mount batteries in the EV conversion. The ICE motor should be a valuable item to someone that is restoring a similar vehicle. Only 49,000 original miles on the engine.

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