I drew up a design for the adapter plate in SolidWorks.  I think it is pretty much done.  I will have to verify the thickness before I cut it out.  I will put the coupler on the motor and measure how much it is sticking out from the face of the motor.  I may make the tapered hole in the back of the coupler a little deeper to allow the bushing to seat in a little further to get the whole assembly a 1/4″ or so shorter.

This was my first foray into using SolidWorks and I have to say that it’s a pleasure to use.  If only it was a Mac OS application and not so ridiculously expensive.

In the past I have used Rhino for things like but it makes it much more difficult to go back and change things.  With this drawing could modify things like the thickness of the ribs by just changing one number.

I finally decided that the way to go was to make a coupler that accepts a QD bushing and bolts to the back of the flywheel.

I drew the part up a couple of times in Rhino until I got it the way I wanted and then decided to draw it up in the emachineshop.com software to see how much it would cost to have them fabricate it.

The price is quite reasonable considering the amount of time it would take me to make it myself.  It’s around $250 for two of the couplers (2 of them was only about $20 more than one so I got two just in case).  Unfortunately, I messed up on one of the dimensions.  I didn’t realize that for the taper on the back of the part they wanted the dimension of the smaller end, not the larger end.  I gave the software the dimension of the larger end and ended up with a hole that was too large.  I fixed the design and ordered another two.  So, I have two expensive paperweights.

The second version seems to be correct. I was kind of guessing on the size of the tapered hole and made it a little small so it doesn’t seat quite as deeply as I would like but it should be fine. I attached it to the motor shaft and spun up the motor and it seems to have very little runout (from what I could tell visually and by running my finger on a smooth portion while it was spinning).

Overall the quality of the part is impressive. The surface finish of the part is beautiful (much better than I could have done). My one complaint is that it took a full month to get the parts (each time). They must be pretty busy at emachineshop…

Now I just have to make the adapter plate. Our CNC machine is about to be online again so I need to get the part drawn up so I can cut it out.  I have measured the transmission (using a Microscribe arm for most of it and a dial indicator and DRO for the dowels and input shaft).  I need about 2.5″ of thickness in the adapter so I will probably use a stack of two 1.25″ plates (I actually found a 2.5″ thick plate on EBay and was tempted but I can’t bring myself to waste that much aluminum).

The controller is capable of pulling 1900 amps out of the batteries at 200 volts.  This is a more than twice what the T-Rex controller I had in there could do.

The main thing that pushed me to switch to the Zilla is the amount of configuration you can do with them.  The T-Rex was a nice controller but it basically had one adjustment which was the max current (well, it also had a rev limit setting).  The Zilla can also return some data about the current operating conditions over the RS232 link.

I’m hoping to have a small linux based computer (probably a Nokia N770) that will grab data from the Zilla and from the battery regulators (probably Manzanita Micro Mk3 Regs).  The regulators will be able to return the voltage of the individual batteries.  The computer could also be set up to modify the settings for the Zilla (like the current limit).

I will probably have the current limit dialed down most of the time since I think maximum limit will break stuff pretty quickly.

Well, a couple of days ago we saw it again and again the next night (in the same area). I decided to try to catch it.

I made a simple trap out of a yogurt container by cutting a small X in the lid and bending it in a little. The hope is that it will go through the X but then have trouble getting back out. That’s the theory at least. I baited the trap with some chopped up shrimp.

Not long after the lights went off we noticed the worm out and about. It was actually going after my brittle star. It had one of the brittle star’s legs in its pincers (or whatever the mouth parts are called). We haven’t seen it over by the trap yet. It does seem to be much bolder tonight. It might be the smell of the shrimp in the tank.

Anyway, I took a video of it and put it on YouTube:

In my old setup, there was a coupler attached with set screws and a key to the motor shaft. This seems to have been ok but the general consensus seems to be that this will fail under higher power setups. Since I plan to hopefully make my car a little more peppy, this is a little of a worry so I am hoping to switch to a more durable taperlock setup.

QD Taperlocks work by using a tapered bushing that has a cut in it. The bushing goes on the shaft of the motor and then goes in a matching tapered hole (on the coupler). There are bolts that pull the bushing into the hole and cause it to clamp down on the shaft of the motor. They also can have a keyway cut in them. You can get a tremendous amount of clamping force with them and they tend to clamp all around the shaft instead of just pushing on one or two points like a set screw coupler.

I would have loved to have ordered one from Electro Automotive but they seem to be unresponsive these days. They don’t already have a pattern for my transmission so I would have had to send the transmission to them. I’m a little scared to do this since they don’t seem to enthusiastic about making adapters anymore. So, my plan is to make the coupler myself (or have a local machinist do it for me).

The easiest way to start is to simply cut the end off a crankshaft and modify that. Unfortunately, the flange on the end of the crank is rather small and wouldn’t really supply enough material to install a large enough taperlock bushing.

I designed a coupler from scratch in Rhino but the problem is that they bolt circle for the taperlock bushing interferes with the bolt circle for the flywheel. To get them to not interfere I had to go up to an extremely large bushing (which has the advantage of being able to handle more than 900 ft-lbs of torque). This makes the coupler get very large which in turn pushes the flywheel farther away from the motor which means that the whole motor/transmission gets a little longer.

It seems like the best solution is going to be to make a brand new flywheel that accepts my exedy twin plate clutch and a taperlock bushing. I drew up another design and it definitely makes for a much neater and simpler design. It allows me to get rid of the ring gear easily and it makes the whole assembly pretty light. My current design should way a little bit over 7 lbs when machined out of steel. Now I just have to find someone to make it for me because I think it’s a little too much for our lathe.

The new transmission came a while ago. The differential that cam with the transmission had been welded by the previous owner so I needed to find a new differential. I decided that since I was replacing the diff it would be nice to have a limited slip in there. There are always a few JDM LSDs on ebay so it wasn’t hard to find one.

I was pretty sure that some modifications would be required to fit the differential and upon opening the case and attempting to fit the diff. it looked like they wouldn’t be too extensive.

There was some webbing in both halves of the case that needed to be ground down so that the differential wouldn’t rub. I also had to replace the bearing from the bell housing side of the differential with one from a 2000 integra type-r (part number 91005-P80-E31). This bearing is a little taller which stops the speedometer gear on the differential from rubbing on the case.

After the modifications the diff appears to fit fine. Now I just have to order the shims, the gap is a little larger than normal so I may have to stack two shims but I don’t see why this would be a problem.

The main change that I am planning on making to the EV is that I will be replacing the transmission with a b-series transmission from a ‘92 Acura Integra. This will make it possible for me to find a much stronger clutch and possible a limited slip differential. The ‘87 transmission was just too old and there aren’t many cars with that transmission making a lot of power so the clutch offerings for it were pretty slim. I probably could have gotten a multi thousand dollar clutch for it if I wanted but with the B series trannsmission I can get a pretty stout clutch for much less.

I’m also going to be rearranging everything under the hood. The controller was towards the middle of the engine bay before and I have decided that I would rather have it as far back as possible to keep it away from the weather. I’m also going to try to finally make the wiring nice and neat since it was a bit of a rat’s nest before.

So, now I have wait for the transmission to arrive, then I have to get a new adapter plate made to attach the motor and get some motor/transmission mounts to put the new transmission in the car. Conveniently there are a few off the shelf motor mounts for that transmission/engine combo since people have been sticking the more powerful b-series motors in that car for quite a while.

I have already transferred some of the old pages over (as you should see on the right).