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I mounted the controller on a finned heatsink attached to the rear wall. This keeps the cables from the motor to the controller very short.
The motor is mounted to a 3/16 inch thick steel plate. The plate is framed with 1.5 inch angle stock, 1/8 inch thick and has 3/16 inch thick
gussets around each mounting hole. Obviously, I could have just started with 1/2 inch thick steel plate, but I'm fighting to keep the weight
down. I added slider rails along the top and bottom edges, and a tab holds a 3/8 inch bolt used to tighten up the belt. A friend at work
machined the hub adaptor for me. It turns out that the original axles were slightly bent. I ordered a new axle and CV joints just to be sure
everything would be straight. After welding, the outer edge of the pulley only has +/- .015 of side to side wobble.
I had bought a pair of idler pulleys, but they weighed 6 lbs each. They have to move fast to follow changes from motoring mode to regeneration mode. So
I made a pair of idlers out of a set of ball bearings and a 2.5 inch diameter aluminum pipe, which only weigh 1.25 lbs each. They are on separate swing arms,
with a pair of springs connecting them to each other. So they follow the belt directly as a pair, and just move slightly as you go from drive to regeneration.
At this point, I can drive the car around the neighborhood to check out the suspension and drive system. Acceleration is great!
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The rear calipers and brake lines are now installed. Ineeded a separate flex line at the pivot point of the rear wheel assembly. |
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The Curtis AC motor controller arrived this week. It's a new model which will work with a 96V nominal battery pack. It has all the vehicle features needed for a complete vehicle controller, including regenerative braking. |
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The controller is mounted in the rear equipment bay, behind the passenger seat. The Heatsink will have air ducted through it from the body side air intake. |
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The motor mounting plate is fabricated from a 3/16 inch thick base plate framed with 1.5" angle stock 1/8" thick to stiffen it. Gussets (3/16 inch thick) are welded in at the motor mounting bolt locations. |
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I made a dummy plate to simulate the motor face and bolted the pulley on it as an alignment aid. This lets me locate the motor mounting plate more accurately. |
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I used a wooden pulley hub adapter over the old axle to make sure the adaptor would fit and to locate the belt. |
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In order to keep things straight, I ordered a new axle assembly. This was turned down to get a straight clean surface to slide the hub adaptor over. Once I have it located on the rear axle assembly and the belt is straight, I will weld the adaptor to the axle. |
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Here the adaptor is welded and the belt set up without any tensioner. If I don’t bounce the suspension, I should be able to test drive it. |
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It's ALIVE!!! After almost 2 years, it's moving under it's own power! Acceleration is great, and the belt only slipped a tooth once under heavy acceleration after I drove it a while and the belt loosened up a bit. |
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This is a shot of the belt drive with a pair of tensioners, so the belt stays tight both in drive and regen modes. Now I can floor it going up the driveway and there is no slippage. Very little pressure was required. |
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I designed my own rollers, with ball bearings inside of a 2.5 inch diameter aluminum pipe. The arms are fairly light, and the response of them is quick, so I can follow the change from drive to regeneration mode. |
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The new digital instrument panel mounts next to the main panel. The volts and amps work perfectly, with negative amps meaning the current is out of the battery, and positive amps correspond to regenerative braking current back into the battery. Regen mode is very smooth. |
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I decided to look into the issues around low speed aerodynamics. It seems like a lot of work has been done with bicycles and human powered vehicles. Race cars usually just chop the rear square, because at high speeds, there's not much you can do to reduce drag. But at lower speeds, a teardrop shape seems to work well. The rear wheel setup works well with this. |
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I angled the rear suspension spring forward a bit to give a somewhat softer effective spring rate and to allow a bit more of a slope to the rear body. |
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At this point, the chassis is complete and I'm ready to start the body. I had to widen the rear end 2 inches on each side because I didn't allow enough clearance to get the wheel off on the side with the brake caliper. Once again, it seems I wind up doing everything 2 or 3 (or 4) times before I'm satisfied with the results. |
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I've put over 60 miles on the chassis just driving up and down the local roads over the past few months. Around 6 people have driven it at this point,
providing invaluable feedback about seemingly mundane issues such as precice pedal placement up to much more critical issues such as brake pedal pressure.
It was a pretty constant bit of feedback that the brake pedal pressure was on the high side, even after I adjusted the balancing bar on the master cylinder.
So after a lot of scrounging at junkyards and going over infor available on the internet, I concluded I couldn't really improve much on the 1988 Fiero
calipers and rotors without going to bigger rotors, which would not fit inside the 14 inch wheels. The obvious option was to use the original Fiero
master cylinder and vacuum booster, but this would also require the addition of a Separate motor-driven vacuum pump. Not the end of the world, but I
was not happy about the weight increase or the complexity that came with this approach.
So I looked into "softer" brake pads, and the best I could find seemed to be the EBC "greenstuff" pads. These organic pads provided a very noticeable
decrease in pedal pressure. In fact, the pedal pressure is now low enough that I feel the brakes are fine as is, with no more tweaking necessary.
At least for now... I guess I'll always keep my eyes open for better options.
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