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Discussion Starter #1
Does anyone know if it's possible to remove the transmission from a chevy bolt motor unit? It's not bolted on like the Leaf motor arrangement, but is there a way? I raise the question, because I'm thinking of using one in a rear wheel drive conversion, instead of a gs450h unit.
 

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The gearbox and motor on the Bolt EV are integrated, so no. Weber has a Youtube video where he disassembles the unit.

My question is why would you want to? The Bolt EV makes pretty fair HP and torque. It's also pretty compact if you pull the inverter and crap bolted to it.

No reason you couldn't "overclock" it, if you're thinking the motor is weak (compared to the GS450H, I'd put it in superior territory), as far as the current you dump into it for short bursts, as there should be plenty of safety factor in the little grocery-getter.
 

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I agree - why not use the complete drive unit, mounted at the rear axle, instead of stripping the motor out and having to provide some other reduction gearing?
 

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Discussion Starter #4
Thanks Remy... I was concerned about losing speed and gaining unnecessary torque. My understanding is that its essentially a transaxle for the front wheels. If so, the final drive is the transmission (7.05:1). If l connect that directly to the rear differential (another final drive) of a w220 S-class, it'll give it even more torque, but slow it down by a factor of nearly 3 - or won't it?..
 

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No...you pull the original diff, put the Chevy in, and run halfshafts out to the hubs. Frankly, I'd go with a Tesla drive unit for that car...
 

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Discussion Starter #6
For real Remy, so would I! Just a little matter of price.. I see Tesla drive units going for $4000+ compared with the 1k or thereabouts for the Chevy Bolt motor
 

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My understanding is that its essentially a transaxle for the front wheels. If so, the final drive is the transmission (7.05:1). If l connect that directly to the rear differential (another final drive) of a w220 S-class, it'll give it even more torque, but slow it down by a factor of nearly 3 - or won't it?..
That's right, the overall gearing (including final drive) of the Bolt unit would be 7.05:1, so there would be too much reduction gearing... which is why you don't do that, and why I suggested this:
I agree - why not use the complete drive unit, mounted at the rear axle...
Then remy_martian suggested it again, with additional details in case my version was not understood:
No...you pull the original diff, put the Chevy in, and run halfshafts out to the hubs.
Of course the whole drive unit (motor with transaxle) needs to fit in the rear, where there is normally only a final drive unit.
 

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Discussion Starter #8
Sorry guys - I was typing in my reply to one of Remys' when you were both giving me the answers I needed. Much obliged 👍
I think putting the unit in place of the rear differential is a fantastic idea. Just didn't know that it was doable. One additional advantage is that I can discard the prop shaft along with the Mercedes gearbox - nice weight saving there.
 

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The Bolt is a bit ugly in that it sits vertical
The complete drive unit has the inverter on top, like all of the other EVs adapted from front-wheel-drive designs; most (including the Bolt) have the charger and other components stacked even higher, on top of the inverter. The motor and transaxle are at the bottom - like every drive unit - as low as a Tesla or anything else. Using any of these vertically-stacked units at the rear of a typical vehicle does mean moving the inverter to behind or ahead of the motor and transaxle.
 

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Discussion Starter #11
If can find a Tesla drive unit for $1k, that'll be a game changer..
 

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If can find a Tesla drive unit for $1k, that'll be a game changer..
$1500 right now, though I've seen one for $1k


If it fits with the same inclination to preserve lubrication scheme...
 

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I raise the question, because I'm thinking of using one in a rear wheel drive conversion, instead of a gs450h unit.
[/QUOTE]

Hey DrGee

Just wondering why your thinking of ditching the gs450h gearbox? It seems like a good unit to me.

Thanks
EvBeddy
 

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Yeah...you're right about the orientation. I've only paid attention to the PR photo


(12:31 ..."transaxle [with motor] weighs 170lb")

It's still looks higher from the axle centerline, though
 

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Just wondering why your thinking of ditching the gs450h gearbox? It seems like a good unit to me.

Thanks
EvBeddy
It's a good unit, but its advantage of not messing around with the drivetrain for "quick and dirty" carries serious issues like weight, reliability, more moving parts, lower efficiency (a lot of stuff sloshing in lubricant and a lot of rotating inertia), keeps the driveshaft, joints and rear end which are lossy and heavy, and displaces a space where you could stuff batteries for better car balance. There's also cost.... that Tesla drive unit costs more or less the same as the trans AND you get the inverter for the money.

The hybrid trans makes a lot of sense if you're converting the hybrid it came in, maybe. But for a car like an S-class, ....?
 

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Hi Remy

Thanks for your reply. There all good points, some that I hadnt thought of. I didnt realise tesla sdu's were as cheap as that.

One benefit of the gs450h in a rwd platform is the easier ability to have a LSD as your keeping the diff. I know you can get a (expensive) quiaffe unit for teslas LDU but theres nothing for the SDU that im aware of.

Evbeddy
 
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