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I don't expect stickshift EVs to be common either, but still I think it's surprising that no one has made a non-luxury-car EV that isn't direct drive. Manual t

by elihu 6y ago

I don't expect stickshift EVs to be common either, but still I think it's surprising that no one has made a non-luxury-car EV that isn't direct drive. Manual transmissions seem like a pretty mature technology at this point. For any car company that already makes a manual transmission car it would be easy to do. They might change the design a little (maybe 3 speeds instead of 5, and use sturdier gears and different ratios). Clearly you don't need a transmission in an EV, and leaving it out is simpler and less maintenance, but still... if it can be done and it makes for a (in some ways) better or more fun car, then it's a shame no one is doing it yet. I'm currently working on converting a Mazda RX-8 to electric, keeping the transmission and clutch. It'll be interesting to see what it's like to drive. IIRC, the motor (Netgain Hyper-9 144 volt dual-ended version) has a max RPM of 8000, which is close to the 9000 rpm redline of the rotary it replaces. The motor is a lot less powerful than what you'd find in a typical Tesla (which I attribute mostly to it being designed to run at a lower voltage), but having a gearshift should make up for at least some of the difference.

jwalton 6y ago
I have a friend who dropped a turbocharged engine out of an old 80s BMW into an RX-8. He ended up having to cut a hole in the firewall and completely redesigning the rack and pinion because the old rack would have gone through the middle of the larger BMW engine. He kept the original gearbox and was always worried the low revving high torque BMW engine was going to murder it. :P
- elihu 6y ago
  Thankfully I don't have that problem. The Netgain motor is pretty big as motors go and it'll be close to the power steering unit, but still I think I've got enough room there. Most of the work so far has been making battery boxes. I've got one under each rear seat where the gas tank used to be, one in the front down low where the radiator used to be, a smaller one above it, and another that goes over the motor (which raises the CG more than I'd like, but the other batteries that basically as low as they can be probably offset it). Weight balance should be about the same. I'll have to do some welding on the back seats, because they're too low for the batteries to fit. Sacrificing about four inches of foam will make for an uncomfortable seat, but it should at least look normal.
  - Tor3 6y ago
    How do you plan to do heating? Even if it doesn't get cold where you live, but you'll still need heat (and maybe A/C) to avoid fogging the windshield when it's humid. An electric heater, powered by the same batteries?
    - elihu 6y ago
      I haven't figured that out yet. Probably an electric heater of some sort.
taneq 6y ago
Yeah, I'd have thought a DC motor plus a two-speed transmission would be a no-brainer for the budget end of the market (at least until high power AC drives come down a bit) but maybe not. What batteries are you using for the RX-8?
- elihu 6y ago
  DC motors are great if you want the most power with the least price, but for a daily driver AC has a few advantages. AC motors are usually zero maintenance because they don't have brushes to wear out, and it's a lot easier to support regen (which I've heard actually makes a big difference to driving experience; people expect the car to slow down when they take their foot off the gas, and it's disconcerting for it to just keep rolling forward like a freewheeling bicycle). AC motors and motor controllers are generally more expensive than, say, a Warp9 and a Zilla, but the price difference is gradually dropping. Probably the price difference between AC and DC for a major manufacturer is even smaller than what's available retail to hobbyists doing conversions. And I think more and more conversions are being done with repurposed Tesla and Leaf drive units. A small, cheap AC motor attached to a 2 or 3 speed transmission would be a lot of fun to drive, I think. No need for a reverse gear even. Maybe not even a clutch or flywheel, if you can match the motor speed with the transmission electronically. My batteries are about 450 pounds of lithium iron phosphate cells. That's generally what's recommended for conversions. Used Tesla packs have much better energy density, but they're more dangerous and need liquid cooling and are awkwardly shaped. I couldn't think of a good place to put them in the RX-8 where they'd be safe.
toomanybeersies 6y ago
In Europe, manual transmissions are generally preferred because they're cheaper, not because they're more fun to drive.
- arethuza 6y ago
  Also European cars tended to have smaller engines, which weren't a great combination with the relative inefficiencies of torque converter style automatic transmissions. However, newer dual clutch style transmissions work pretty well with small engines - I have a car with a 1l engine and DCT and it is a delight to drive.
- throwaway0a5e 6y ago
  Manual transmissions are preferred because on a continent where 1L engines drag around 4000lb cars (because displacement taxes) being able to shift when you want (as opposed to just having to live with whatever gear the OEM engineers who have emissions to consider think you should be in) translates into a much improved driving experience. They're marginally cheaper but the real key is that they let the consumer side step engineering decisions that were made against the consumers interests.
  - taneq 6y ago
    I thought the cars did that for you by detecting emissions tests and switching to 'emissions mode' just for the test?

by elihu 6y ago

jwalton 6y ago

I have a friend who dropped a turbocharged engine out of an old 80s BMW into an RX-8. He ended up having to cut a hole in the firewall and completely redesigning the rack and pinion because the old rack would have gone through the middle of the larger BMW engine. He kept the original gearbox and was always worried the low revving high torque BMW engine was going to murder it. :P

elihu 6y ago
Thankfully I don't have that problem. The Netgain motor is pretty big as motors go and it'll be close to the power steering unit, but still I think I've got enough room there. Most of the work so far has been making battery boxes. I've got one under each rear seat where the gas tank used to be, one in the front down low where the radiator used to be, a smaller one above it, and another that goes over the motor (which raises the CG more than I'd like, but the other batteries that basically as low as they can be probably offset it). Weight balance should be about the same. I'll have to do some welding on the back seats, because they're too low for the batteries to fit. Sacrificing about four inches of foam will make for an uncomfortable seat, but it should at least look normal.
- Tor3 6y ago
  How do you plan to do heating? Even if it doesn't get cold where you live, but you'll still need heat (and maybe A/C) to avoid fogging the windshield when it's humid. An electric heater, powered by the same batteries?
  - elihu 6y ago
    I haven't figured that out yet. Probably an electric heater of some sort.

taneq 6y ago

Yeah, I'd have thought a DC motor plus a two-speed transmission would be a no-brainer for the budget end of the market (at least until high power AC drives come down a bit) but maybe not. What batteries are you using for the RX-8?

elihu 6y ago
DC motors are great if you want the most power with the least price, but for a daily driver AC has a few advantages. AC motors are usually zero maintenance because they don't have brushes to wear out, and it's a lot easier to support regen (which I've heard actually makes a big difference to driving experience; people expect the car to slow down when they take their foot off the gas, and it's disconcerting for it to just keep rolling forward like a freewheeling bicycle). AC motors and motor controllers are generally more expensive than, say, a Warp9 and a Zilla, but the price difference is gradually dropping. Probably the price difference between AC and DC for a major manufacturer is even smaller than what's available retail to hobbyists doing conversions. And I think more and more conversions are being done with repurposed Tesla and Leaf drive units. A small, cheap AC motor attached to a 2 or 3 speed transmission would be a lot of fun to drive, I think. No need for a reverse gear even. Maybe not even a clutch or flywheel, if you can match the motor speed with the transmission electronically. My batteries are about 450 pounds of lithium iron phosphate cells. That's generally what's recommended for conversions. Used Tesla packs have much better energy density, but they're more dangerous and need liquid cooling and are awkwardly shaped. I couldn't think of a good place to put them in the RX-8 where they'd be safe.

toomanybeersies 6y ago

In Europe, manual transmissions are generally preferred because they're cheaper, not because they're more fun to drive.

arethuza 6y ago
Also European cars tended to have smaller engines, which weren't a great combination with the relative inefficiencies of torque converter style automatic transmissions. However, newer dual clutch style transmissions work pretty well with small engines - I have a car with a 1l engine and DCT and it is a delight to drive.
throwaway0a5e 6y ago
Manual transmissions are preferred because on a continent where 1L engines drag around 4000lb cars (because displacement taxes) being able to shift when you want (as opposed to just having to live with whatever gear the OEM engineers who have emissions to consider think you should be in) translates into a much improved driving experience. They're marginally cheaper but the real key is that they let the consumer side step engineering decisions that were made against the consumers interests.
- taneq 6y ago
  I thought the cars did that for you by detecting emissions tests and switching to 'emissions mode' just for the test?