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Leaf transaxle or not?

Posted: Thu Jul 02, 2020 8:21 pm
by DaveH
I have been thinking about my potential project. It looks like the Leaf motor would be a good solution for my VW T2. About the right amount of power, not too heavy, not too expensive.

I'm trying to work out whether it would be best to use the motor and transaxle, or just the motor coupled to my old transaxle. Ideally I would use the Leaf box, but can anyone offer some advice to help me? I can see pros and cons as follows.

Leaf transaxle
+ lighter
+ more efficient
+ quieter
+ ratio ok? (equivalent to somewhere between 2nd and 3rd gear)
- need special drive shafts
- don't know if it will fit (but should be ok without inverter attached)

VW transaxle
+ option of changing gear
+ looks like stock
+ can use original drive shafts
+ can mount inverter on motor (I think)
- need custom coupler and adapter plate
- limited life left (has 160k miles on it)

Someone tell me if I have assumed wrongly or left out some important details? I want this to be a bolt-on conversion, I don't want to modify the body except for drilling holes.

Re: Leaf transaxle or not?

Posted: Thu Jul 02, 2020 8:54 pm
by zippy500
As you are in the (UK like me) you may want to have a look at this thread,

viewtopic.php?f=9&t=543

I had plans to to use the leaf transaxle in my Rwd car and lose all cars running gear and save weight.

to keep it simple with regards to class change to electric, I think the easiest route would be just a motor/engine change.

Think this is the route I will take( although the ways things are I don't think I'm going down any route :( )

Re: Leaf transaxle or not?

Posted: Thu Jul 02, 2020 9:29 pm
by Cookie6000
I weighed up the options too on my Audi8e build and from a cost perspective, stuck with the simpler bolt of the motor onto the Audi box. Fabricating bespoke output shafts or hubs can cost €€€ compared to a just knocking up a 20mm adapter plate! I also see the benefit of having the luxury then of both acceleration and cruising speed having the 5 speed manual. I presume you plan to upgrade brakes and suspension to match, seeing as it is a T2 so having that extra couple of ratios to play with on the motorway might help the bus.

Re: Leaf transaxle or not?

Posted: Thu Jul 02, 2020 9:39 pm
by arber333
Vw bug transmission is actually really efficient piece.
You can't go wrong using it. You can easily get to top speed.

Myself I am biased towards fixed gearbox. Less moving parts and smoother drive... Though latest research showed increase in consumption due to winding losses at high rpm.

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 4:38 pm
by DaveH
Thanks for the replies, this is really valuable info.

Has anyone tried changing gear with electric while on the move, without a clutch? I have seen one or two conversions where they kept the clutch and flywheel but most of you on this forum seem to just use a straight coupler.

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 5:37 pm
by Isaac96
DaveH wrote: Fri Jul 03, 2020 4:38 pm Has anyone tried changing gear with electric while on the move, without a clutch? I have seen one or two conversions where they kept the clutch and flywheel but most of you on this forum seem to just use a straight coupler.
Yes. It works. It often takes a second or two to get the revs to match up (using the synchros) but does work well. Upshifting will probably be improved by a little regen. I'm probably going to implement some sort of revmatching system in the future (activated by clutch pedal maybe?)

-Isaac

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 5:47 pm
by mdrobnak
Could probably do something with the 'idle' code. I'll probably need something like that with my gearbox as well (and that's with a clutch).

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 6:40 pm
by zippy500
some people have fitted a switch on the gear shift , to put the board in neutral to disable the regen for gear change

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 6:46 pm
by Isaac96
zippy500 wrote: Fri Jul 03, 2020 6:40 pm some people have fitted a switch on the gear shift , to put the board in neutral to disable the regen for gear change
Putting the board in neutral means it can't go back in gear unless RPM is low (dirchrpm parameter changes the limit). That parameter is limited to 2000 so switching to neutral is not very helpful.

Others have used the BMS input to reduce allowable power. AFAIK this works well, but I'm using that input to limit power in reverse (my BMS is not talking to the inverter, I monitor it myself with screen and buzzer.)

-Isaac

Re: Leaf transaxle or not?

Posted: Fri Jul 03, 2020 7:18 pm
by arber333
zippy500 wrote: Fri Jul 03, 2020 6:40 pm some people have fitted a switch on the gear shift , to put the board in neutral to disable the regen for gear change
Thats me :)
https://mazdamx3ev.wordpress.com/2018/0 ... lopka-ven/
I fitted a switch that triggers BMS input of inverter and i had it setup with 0 regen. So when i push that button ACIM rotor becomes a piece of iron and there is no resistance from the synchros. Maybe shifting feels like 1/2s late but it is nonetheless effective.
I can assure you it is done naturally without applying throttle. Because motor does not shake it is quite smooth.
I never tried this with PMSM motor. I imagine it would be the same.

With EV motors clutch is a redundant part. The important clutch as we say it would be Lovejoy coupler or similar that dampens the force of transition from regen to traction force.

Re: Leaf transaxle or not?

Posted: Sat Jul 04, 2020 5:45 am
by johu
Works well with Leaf motor also. My setup is clumsy, I have to touch the brake and push “cruise set-“ twice to disable regen. Then I can shift. That said there is hardly any need to use another gear than 3rd unless you want to launch in second to annoy fossil cars ;)

Re: Leaf transaxle or not?

Posted: Sat Jul 04, 2020 8:58 am
by Kevin Sharpe
DaveH wrote: Fri Jul 03, 2020 4:38 pm Has anyone tried changing gear with electric while on the move, without a clutch?
Shifting without a clutch :)


Re: Leaf transaxle or not?

Posted: Sat Jul 04, 2020 9:33 am
by DaveH
Ah! I've been watching most of Damien's videos but I must have missed that one. Very smooth.