Motor Performance Test

I heard back from D&D Motor Systems this morning. It seems the motor is a stock motor – no temperature or speed sensing. I’ll need to figure out what to do in regards to the speedometer.

One of the other CitiCar owners I’ve been speaking with mentioned he was considering using a speedometer based on GPS. My concerns with GPS is in situations that you are unable to receive a signal. I want to know my speed immediately, in real time, with accuracy, regardless of where I am. I’m lacking in the accuracy department at the moment where my speedometer seems to think I’m going 4 miles faster than I really am. Perhaps I need to inflate my tires.

Along with a few answers to my questions, D&D Motor Systems also sent along a performance report of the motor.

Engineering Performance Test for ES-40D-56

The stock motor that came with the car has the following information on its plate:

Ratings Plate on a stock 6HP CitiCar Motor
Time RatingINT
MOD5BC 49 JB 327 C
Serial NoAMN
CitiCar specifications on a 6HP motor

I’m not clear on how to compare motors. At first, I thought it was simply comparing which motor had the most horsepower. However, HP is variant based on the load. Voltage is similar. RPM’s… Let’s just say there is so much involved when comparing motors. I had to start reaching out for something to compare.

ComparisonStockD&D Motor
RPM40001444 – 5020
Amps12552.5 – 583.5
Horsepower6in: 3.34 – 30.70
out: 1.90 – 19.24

I feel a bit confused. The motor is both better and worse… I’m certain I’m comparing apples to oranges here since I don’t have a similar table for the stock motor. I’ve heard from another CitiCar owner that the amps can shoot up pretty high on the stock motor while going up a hill. This brings me to wonder, how did General Electric know what to stamp into the motor plate?

As stated in the owners manual, the CitiCar has a 250 amp fuse on the motor.

The same is true driving up long, steep hills. By driving in first speed, and sometimes second speed, under these conditions, you are likely to blow the Citicar’s 250-amp fuse located in the controller box behind the seat.

CitiCar 1976 ½ Owners Manual, Sebring-Vanguard, 1976, page 19

The Mother Earth News article about the CitiCar in Israel had also mentioned the range of amps with the stock motor.

Although initial current draws can reach 500 amps, the average pull at cruising is around 100 amperes.

Israel’s Solar Powered Car, The Mother Earth News, September/October 1980, page 120

Even at that rate, it appears that the new motor will have cruising speeds at 50 amps; half of what the CitiCar can do.

I plugged the performance numbers for the ES-40D-56 motor into an excel spreadsheet and started making some graphs. I like visuals, and I thought it may reveal a pattern and help to compare against with the stock motor that came with the CitiCar.

I saw lots of compounding curves. I wasn’t sure if I was onto something, but I started out comparing RPMs. At 4000 RPM, I assumed the CitiCar motor would use 125 amps and deliver 6 Horsepower – the ratings on its motor plate.

I tried to make a few formulas in the spreadsheet. At 4000 RPM, the new motor would be using around 75 Amps and 4.7 HP. If that’s the case, it’s got a much higher efficiency at only half the amps with less HP to maintain that load/speed. Unfortunately, I’m thinking in a linear scale, so at 4000 RPM’s, it would be just a bit higher for HP and amps – but not by much.

I’m learning about electric motors, and slowly grasping at how to compare them. I believe it will be an improvement. If my calculations are correct, this means that the motor can go further on the same amount of energy.

Coupling the improvement in the motors efficiency with an actual motor controller will further extend the range. I also purchased two more batteries last week to double the range and lessen the load on each of the Chevy Volt batteries.

Other News

In other news, the garage has been cleaned to a point that it is actually organized. Shelving units for indoor gardening have been broken down and moved back into the garage. I have a whole shelving unit dedicated to CitiCar parts. I even have my screw drivers all in one place. Usually I’m having trouble just finding one screwdriver – but now I’m having trouble fitting them all into one container.

Holding CitiCar motor in place

After a great deal of effort, the stock motor is back on the car. The thing is very heavy and difficult to move around while you are laying on the floor.

Battery terminal with nut

A battery nut arrived in the mail, but again – it’s too small. I decided to order nuts that are 7/16 in size, as well as in metric for M8 and M10. I feel like one of those has got to work.

I started on replacing the differential fluid over the weekend, but I got stuck trying to remove the breather cap – which you shouldn’t do. After watching a few videos, I found the filter and drain plugs. I had three #8 Allen wrenches to remove the drain plug, but I had to order a #10 for the filter plug.

I purchased an old General Electric Motor Bumper for a club car to put inside the armature after I saw a video of someone mentioning not to forget to transfer the bumper into your new motor. It’s supposed to help make the motor a little quieter. Maybe… we shall see. I like the wine the motor makes. I just didn’t see it inside my motor and would like to try it out.

I also started playing with an Aukey DRA5 dash cam.


D&D Motor Systems ES-40D-56
25 Qty 7/16-14 Zinc Plated Serrated Flange Hex Lock Nuts (BCP272)7/16″ > 3/8″
Flange Nuts Hex Lock Self-Locking Metric Thread Serrated Nut 304 Stainless Steel Assortment Kit 125Pcs,M3 M4 M5 M6 M8 M10 M12Metric #8, #10 > 3/8″
Pico 0852PT 3/8″ Stainless Steel Battery Hold Down Stud Nut 2 per PackageToo small
EKLIND 14620 10 MM Long Series Hex-L Key allen wrenchFilter Plug
Chevy Volt BMS w/Bluetooth for 48v 12 cell battery w/cell balance & charger contgoes with batteries
NEW Lithium Ion Chevy Volt 48vdc 2kwh 50ah battery Golf Cart Off Grid Solar EVmore range, shares the load
Club Car Electric GE Motor Bumper (Fits 1982-Up)Curious on quiet noise
AUKEY Mini Dash Cam 1080p Full HD Dash Camera with 1.5” LCD Screen Car Camera with 170° Wide-Angle Lens, G-Sensor, WDR, Motion Detection, and Clear Night RecordingFor fun…
Stuff I’ve purchased / ordered

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