FWD / Automatics

[CalebMo44]

Hello all!

First post after lurking here heavily the last week or so. Been doing the same on the DIY electric car forum. I've watched approx 60 of Damien's videos as well.

Despite the "Subject" field of this thread, my first build will very likely be a RWD/Manual 280 or 300z.

HOWEVER, I'm in the drinking-from-a-firehose phase of learning this stuff. I'm struggling to re-sort the basics in my head. I've been looking at the Wiki, but I'm not sure how much it's been updated (I would be ok with sorting things there as I learn), and just searching the board for "FWD" isn't helpful.
SO, I started out my EV education via watching EV4U's videos, where he does ALL-NEW component ($$$$$) conversions. (Even if you have problems with his work, I found some of the basics very helpful.) He says despite doing, and knowing people who have done, automatic transmission conversions, no one would do it again. I understand the extra work with that sort of conversion on an automatic (what he explains, plus I've read other things about maintaining vacuum pressure or some such stuff?).

Question 1: on hybrid transmission-style conversions, what are the main issues with doing this to an automatic? I'm assuming it's not a problem in this type of convert. I saw the BMW Z3 thread, which is an automatic.

Question 2: on these conversions, I'm having trouble visualizing how it would even be possible on a FWD car. Obviously using a purpose-built Electric drivetrain that connects directly to the axle like from a Tesla or Leaf makes sense. But a Hybrid transmission on a FWD? I can't see how that works. Please let me know if I'm being a car dummy and if there's examples!

While I'd like to do a Z as mentioned above, I would love to do a hatch down the road and those are generally FWD.

Thanks, all!

[johu]

Hybrid transmissions, no matter if RWD or FWD always contain two electric motors and a mechanism that can relay ICE torque to the wheels at variable speed (eCVT). They do not use a lossy fluid clutch (is it called that?) of non-hybrid automatic transmissions.

The Toyota Prius has a hybrid transmission that has the shape of a typical FWD transmission. The Lexus GS450h for example looks like a typical RWD transmission.

[muehlpower]

fluid clutch (is it called that?)

"torque converter" oder "drehmoment Wandler", Because when the speed difference is large, they output more torque than the driving motor.

[CalebMo44]

I'm going to answer my own questions from above as I learn for no other reason than to allow others to search and find answers should they have them. (No, I do not have complete answers yet.)

- Question 2: There are FWD EV's and Transaxles*. They are listed on the "Motors" wiki page (https://openinverter.org/wiki/Motors) in the column that specifies FWD/RWD/AWD of each "motor".
Currently listed as FWD are:
Toyota/Lexus MGR Rear Transaxle - Q211
All Prius/Lexus models in the series P111 thru P610
Nissan Leaf Transaxle (both generations) EM57 & EM61
Tesla Small & Large Drive Units (listed as only S&X models)
Mitsubishi Outlander PHEV Front Transaxle

*As you may notice, these are all "TRANSAXLES", and thus have two connections for Right & Left drive shafts that connect to the (front) wheels. This is in contrast to transmissions such as the Lexus GS450h, which have ONE output shaft and are meant to be mounted in the front of the car, and drive said shaft to the rear in a RWD configuration.

Yes, there are other configurations, and as this whole enterprise demonstrates, parts meant for one thing can be used for another. But, in simple terms, there are FWD transaxles from Prius and Leaf models that can be used in a FWD EV conversion. (Duh. Stupid me.)

Still waiting on info about Question 1 and Manual vs Automatic, but I have a better grasp as I've seen builds from here use manuals and leave the original gearbox. This allows for the car's original gearing setup and reverse. I've also seen "You're doing it wrong" Damien do this on his E39 Land Yacht build and then eventually switch it to an automatic!

[jrbe]

That might fit the dictionary definition of transaxle but it's not how it's used typically in the car world.
Transaxles are longitudinal, so input shaft coming in the front or rear and axle stubs out the sides.

No reason to use an automatic if electric only. Electric motors have great torque at 0 rpm. The torque converter and all the unnecessary stuff will just waste energy.

Hybrids get into controls complexity which gets very complicated very quickly. Slippage, throttle control, torque balance, communication, safeties, battery, emissions, etc.

Honda, Hyundai and other hybrids have the electric motor in the flywheel and can use that to assist or regen.