Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Adding these electric motors to the back wheels of my FWD gas car?

electrabishi · 04-02-2017, 05:04 PM

Although I haven't seen any research papers on the subject with respect to this application, I can prove it to you. Or you could prove it to yourself. Go get two small DC motors. Little ones like you find in a cheap kids toy car. Wire them in series across a 6V battery. They will both start spinning about the same speed if they are the exact same motor. Then grab onto one motors shaft and slow it down and you will hear the other one speed up. You could go even further and totally stop the one motors shaft. Although the torque will increase on this motor, the other motor will spin a lot faster. Just remember the current will always be the same through the series circuit. The motors will share their voltage in direct proportion to their speed.

Warp11 weighs 243#
Warp9 weighs 143#
Warp7 weighs ~100#
A 6.7" motor weighs ~67#

Be careful in reading the Motor Torque RPM charts. They can confuse you if you are not familiar with all the test conditions. For example the torques shown will be at a certain speed with a certain load on the shaft. For accelerating from a stop try to find the locked rotor torque and it will be extremely high. And as the RPM on the motor rises the torque will slowly drop. And as Jay said it will also work naturally with the gas engine taking up at higher RPM as the torque on the electrics drop to almost an insignificant contribution.

Dyno results for my Pinto are here http://www.dragtimes.com/1978-Ford-P...phs-15453.html

Other details here http://www.dragtimes.com/Ford-Pinto-Timeslip-15453.html

and here Mike Willmon's 1980 Ford Pinto

Yes adding these motors to the beam axle will increase unsprung weight. Which is I would advise not to go with a WarP11 motor, thats way more than is needed for the desired outcome. I might argue more for a 6.7" or the WarP7 (which is 7.25"). Mounting right to the axle would allow coupling to the hub with a gear set or a 50 roller chain. Tension would be taken up in its mount and would not change with position of the axle.

04-02-2017, 05:04 PM	#38 (permalink)
electrabishi electrabishi Join Date: Apr 2017 Location: Anchorage, Ak Posts: 6 Thanks: 0 Thanked 5 Times in 5 Posts	Adding these electric motors to the back wheels of my FWD gas car? Although I haven't seen any research papers on the subject with respect to this application, I can prove it to you. Or you could prove it to yourself. Go get two small DC motors. Little ones like you find in a cheap kids toy car. Wire them in series across a 6V battery. They will both start spinning about the same speed if they are the exact same motor. Then grab onto one motors shaft and slow it down and you will hear the other one speed up. You could go even further and totally stop the one motors shaft. Although the torque will increase on this motor, the other motor will spin a lot faster. Just remember the current will always be the same through the series circuit. The motors will share their voltage in direct proportion to their speed. Warp11 weighs 243# Warp9 weighs 143# Warp7 weighs ~100# A 6.7" motor weighs ~67# Be careful in reading the Motor Torque RPM charts. They can confuse you if you are not familiar with all the test conditions. For example the torques shown will be at a certain speed with a certain load on the shaft. For accelerating from a stop try to find the locked rotor torque and it will be extremely high. And as the RPM on the motor rises the torque will slowly drop. And as Jay said it will also work naturally with the gas engine taking up at higher RPM as the torque on the electrics drop to almost an insignificant contribution. Dyno results for my Pinto are here http://www.dragtimes.com/1978-Ford-P...phs-15453.html Other details here http://www.dragtimes.com/Ford-Pinto-Timeslip-15453.html and here Mike Willmon's 1980 Ford Pinto Yes adding these motors to the beam axle will increase unsprung weight. Which is I would advise not to go with a WarP11 motor, thats way more than is needed for the desired outcome. I might argue more for a 6.7" or the WarP7 (which is 7.25"). Mounting right to the axle would allow coupling to the hub with a gear set or a 50 roller chain. Tension would be taken up in its mount and would not change with position of the axle.