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Simon TT · 08-29-2023, 05:13 PM

I have a 2004 Smart Roadster Coupe, it weighs just 800kg(1800lbs), is only 1.2m(47" or whatever weird completely random uint of measurement you use for car height) tall, has a 60KW 3 cylinder 700cc rear-mid engine mated to an absolutely awful 6 speed automated manual driving the rear wheels.

I love this car, but the transmission shifts incredibly slow, combined with the fact that the tiny engine NEEDS revs and boost to accelerate sensibly, I crave a little electric boost sometimes. When I make a turn the transmission takes a couple secs to shift, then the engine takes its time to make power resulting in basically having 0 power while turning, which isn't nice. If I had just a little power that would be much nicer, also during gear shifts a little extra power, so I don't loose speed, would be greatly appreciated.

I would like to add small (2-5KW) motors to the front wheels and a very small battery (~5kWh), just enough to drive ~15km pure electric.
The whole system shouldn't be to heavy, since you really feel every kg in such a light car. Ideally the electric motors should have enough torque to start the car from a standstill, if it can do that it could replace the reverse gear, the alternator/battery and the starter.

Reverse gear: simple just reverse the polarity of the motors and you have reverse.

Alternator/battery: use the motors as regenerative brakes. I don't need much power anyway, I don't use the ac, stereo or any other unnecessary stuff. If the power gets to low just use the motors like a normal alternator.

Starter: the motors should be able to push the car to ~10kph meaning I can bump start the engine like LMP cars.

The question is just what motors should I use and how to mount them. my car is currently on 25mm spacers but 30-35mm should be easily possible. mounting them directly onto the rims seems the most solid to me. I habe a CNC so making a mounting plate shouldn't be a problem.

What motors should I use? I saw some scooter motors which are rated up to 120kph (would be really nice) although they are probably not slim enough to fit.

08-29-2023, 05:13 PM	#1 (permalink)
Simon TT EcoModding Lurker Join Date: Dec 2022 Location: Bavaria Posts: 10 BMW - '09 BMW E91 325d 90 day: 50.38 mpg (US) SRCE - '04 Smart Roadster Coupe 60KW Thanks: 0 Thanked 0 Times in 0 Posts	Very Mild Hybrid I have a 2004 Smart Roadster Coupe, it weighs just 800kg(1800lbs), is only 1.2m(47" or whatever weird completely random uint of measurement you use for car height) tall, has a 60KW 3 cylinder 700cc rear-mid engine mated to an absolutely awful 6 speed automated manual driving the rear wheels. I love this car, but the transmission shifts incredibly slow, combined with the fact that the tiny engine NEEDS revs and boost to accelerate sensibly, I crave a little electric boost sometimes. When I make a turn the transmission takes a couple secs to shift, then the engine takes its time to make power resulting in basically having 0 power while turning, which isn't nice. If I had just a little power that would be much nicer, also during gear shifts a little extra power, so I don't loose speed, would be greatly appreciated. I would like to add small (2-5KW) motors to the front wheels and a very small battery (~5kWh), just enough to drive ~15km pure electric. The whole system shouldn't be to heavy, since you really feel every kg in such a light car. Ideally the electric motors should have enough torque to start the car from a standstill, if it can do that it could replace the reverse gear, the alternator/battery and the starter. Reverse gear: simple just reverse the polarity of the motors and you have reverse. Alternator/battery: use the motors as regenerative brakes. I don't need much power anyway, I don't use the ac, stereo or any other unnecessary stuff. If the power gets to low just use the motors like a normal alternator. Starter: the motors should be able to push the car to ~10kph meaning I can bump start the engine like LMP cars. The question is just what motors should I use and how to mount them. my car is currently on 25mm spacers but 30-35mm should be easily possible. mounting them directly onto the rims seems the most solid to me. I habe a CNC so making a mounting plate shouldn't be a problem. What motors should I use? I saw some scooter motors which are rated up to 120kph (would be really nice) although they are probably not slim enough to fit.