Manual vs. Automatic Tranz

What is the downside with using an automatic tranny when building an EV and searching for the right Donor car?

Will an automatic only let you rev it up to certain speed? Couldn’t you technically put the auto tranny into 2nd and have the same capabilities?

[QUOTE=PATZKE;3543]What is the downside with using an automatic tranny when building an EV and searching for the right Donor car?

Will an automatic only let you rev it up to certain speed? Couldn’t you technically put the auto tranny into 2nd and have the same capabilities?[/QUOTE]

If you understand Auto-Tranny’s then you know they are all belt driven and depending on the pressure to “power” ratio it adjusts and switches gears to what the cars power output would be. (typically taken care of with a computer)

well if you do an EV you have to reprogram the ECU to accept the proper power options and shift points… where as with a manual you put in clutch, select gear, let out and you dont have to worry about stalling the car because you dont have to worry about an active flywheel to keep the car running because the motor wont be spinning at all. so thus just press gas when you want to and your off when you want to be… WAY easier.

[QUOTE=FEUS;3546]If you understand Auto-Tranny’s then you know they are all belt driven and depending on the pressure to “power” ratio it adjusts and switches gears to what the cars power output would be. (typically taken care of with a computer)

well if you do an EV you have to reprogram the ECU to accept the proper power options and shift points… where as with a manual you put in clutch, select gear, let out and you dont have to worry about stalling the car because you dont have to worry about an active flywheel to keep the car running because the motor wont be spinning at all. so thus just press gas when you want to and your off when you want to be… WAY easier.[/QUOTE]

just the answer i was looking for. :smiley: Was just curious.

I’m searching frantically for a donor car. :frowning:

[QUOTE=PATZKE;3548]just the answer i was looking for. :smiley: Was just curious.

I’m searching frantically for a donor car. :([/QUOTE]

thats easy… just find a manual car with a blown motor :wink: usually you can get them for a steal. I’ve been looking at an Acura NSX with high miles thinking about picking it up since i need an all aluminum chassis/body for what i’m working on, but i’m still not sure i want to spend the 4K on a shell or not yet.

[QUOTE=FEUS;3549]thats easy… just find a manual car with a blown motor :wink: usually you can get them for a steal. I’ve been looking at an Acura NSX with high miles thinking about picking it up since i need an all aluminum chassis/body for what i’m working on, but i’m still not sure i want to spend the 4K on a shell or not yet.[/QUOTE]

i know i just cant find the right car…

i’m trying to spend <$2000 on a donor. I’ll be able to do it i just have to find the right deal. I would like to use a Porsche 944… I may just have to go with a goofy lookin’ car. :wink:

[QUOTE=PATZKE;3550]i know i just cant find the right car…

i’m trying to spend <$2000 on a donor. I’ll be able to do it i just have to find the right deal. I would like to use a Porsche 944… I may just have to go with a goofy lookin’ car. ;)[/QUOTE]

Today i found the neatest little car:

it’s a Honda Civic Del Sol

sweetest lookin thing ever. :stuck_out_tongue:

Looking on Ebay Motors, there are several Charities that regularly auction “donated cars” cheap. Depending on your location, this might be a good place to find your donor car.

The bad part about auto’s is they are hydraulicly operated. They use clutch packs and bands to hold planetery gears to give you different ratios. You also have the torque converter. To get it all to work you have to run a pump. The takes a lot of power, not something you have a lot of in an electric car.

As far as an auto being belt driven I have never heard of that outside of maybe motorcycles.

[QUOTE=Seafarer12;3585]The bad part about auto’s is they are hydraulicly operated. They use clutch packs and bands to hold planetery gears to give you different ratios. You also have the torque converter. To get it all to work you have to run a pump. The takes a lot of power, not something you have a lot of in an electric car.

As far as an auto being belt driven I have never heard of that outside of maybe motorcycles.[/QUOTE]

Manual transmissions are the better choice for simplicity. Automatics can be made to work, but you will need a separate moro driven pump for the hydraulics and a manual valve body for the shifting so you can hold a gear to the higher rpm required for an electric motor.
-enganear

http://craigslist.org

each big city has one
check it out.
thanks
jesse

All autos waste energy because when they shift, for a brief amount of time, 2 gears are engaged at the same time, plus the torque converter is like a slipping clutch - even the ones with a lock-up clutch in the torque converter except on steady state high way speeds. All this wasted engergy is send via ATF to the trans cooler in the form of heat. Ao, even if you get past the technical challenges of making the auto think it still has its ICE, to you want to throw away that much power ? You will only need one or 2 gears in the manual trans anyway, depending on your driving speeds.

now there is a shell i would love to get :smiley: and to think of it even further as an EV…now that is simply… wow…:whoo:

I am still learning these EV

You could use an automatic transmission for your EV but it would be more beneficial to use a manual. There would be no need for any external pumps as I have seen suggested in this post. The Electric motor would just be replacing Engine. Automatic transmissions have pumps within them and the torque converter is part of that system. As long as the electric motor will spin to the desired RPM required to turn the torque converter you will get function. I would think that if you did go this route that there would be an issue with efficiency due to parasitic drag from fluids and you might experience a lag due to the electro motor moving a 0 rpm during your stops and then having to spin to rpm to get the system functioning. Might be like doing a neutral slam often depending on how heavy your foot is.

One advantage of automatic car is that if you want to overtake someone you don’t have to worry about which gear to select to make sure you get round them in time. Just floor it and the automatic gears do all the work for you!