# A/C motor direct diving 4x4 tcase



## Moltenmetal (Mar 20, 2014)

Tipover would be your best person to ask. I know nothing about 4x4 transfer cases, but can say that it would seem to me that a hill-climbing 4x4 that you also want to drive on the highway would have the biggest need for multiple gear ratios of any application. I think you're going to want to keep the transmission. The clutch is optional though.


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## dcb (Dec 5, 2009)

there's been a few, like the little suzukis, and in OZ
https://www.google.com/webhp?source...2&ie=UTF-8#q="transfer+case"+site:evalbum.com

Top Speed	51 MPH (82 KPH)
will climb 30 deg gravel slope in 4wd low ratio (wheels spinning, lots of fun).
http://www.evalbum.com/1149
(Lead acid batteries too)


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## evforme? (Jul 23, 2015)

That's helpful, I didn't think to look outside this forum much.

I was thinking of being geared not so much for rock climbing but just general purpose stuff, so low geared differential for the low speed hilly stuff or just for getting going and they can range anywhere from 1.5:1 and up very low if you add doublers into the mix. and the 1:1 hi gears for speeds up to about 120k in a squad body 4 door tracker/sidekick.

I was thinking an ac35 or better higher voltage setup, or maybe a remy , something that could rev a bit higher, the hardware isn't the issue ATM its more about finding practical experience with operating in these rpm ranges to do this kind of work, I don't feel like pioneering anything this time around.


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## Moltenmetal (Mar 20, 2014)

Having a couple gearings to select between is a practical necessity with affordable AC motors- unless you can repurpose an OEM EV motor. Can your transfer case do that well enough? Perhaps. My AC50 conversion would be perfectly driveable and fun with only 2nd and 4th gears. First is just for showing off, 3rd and reverse for convenience rather than necessity. I've only been in 5th a couple times...


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## evforme? (Jul 23, 2015)

Moltenmetal said:


> Having a couple gearings to select between is a practical necessity with affordable AC motors- unless you can repurpose an OEM EV motor. Can your transfer case do that well enough? Perhaps. My AC50 conversion would be perfectly driveable and fun with only 2nd and 4th gears. First is just for showing off, 3rd and reverse for convenience rather than necessity. I've only been in 5th a couple times...


That's what got me thinking, a lot of the people say just that. They keep it 2nd and forth or so on and rarely use the other gears, you can do that gear spread with the right did tcase combo and save 100 pounds of transmission.

A couple people on EV album even seem to make it happen with DC motors, so not an original thought but I couldn't find anyone that's done it, it seems 4x4s aren't real popular on this forum though.


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## akseminole (Jan 5, 2014)

evforme? said:


> A couple people on EV album even seem to make it happen with DC motors, so not an original thought but I couldn't find anyone that's done it, it seems 4x4s aren't real popular on this forum though.


It does seem that way.

I suspect that it is a different realm of car culture.
Until recently, electric enthusiasts seem to have been people who wanted to increase efficiency or save the planet, etc.

There is nothing wrong with either of those goals.

As an off-road enthusiast, I am in the search for torque. Which is what leads me to retain my transmission. In fact, I want More gearing in my build. 

Though it may not be necessary. I guess we shall see.


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## dcb (Dec 5, 2009)

I guess I don't understand, regardless of the application, you have to determine the operating parameters, i.e. how much wheel torque over rpm, vs weight and drag. You have to examine the transfer case candidates and their ratios and losses and the available motor/controller and differential selections and available batteries, etc, and see what makes sense for what you want to do.

or put a lift kit and some mudders on a p90d  (though a higher ratio would be good)


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## akseminole (Jan 5, 2014)

If I were a millionaire, I have long had a daydream about making a Lamborghini Trar. 
I'm not though.

I suggested to someone I know that the "easiest" way to accomplish the dreams they had would be to use two wrecked Tesla's so they would have the full power motors on both ends of their rock buggy. But they don't have the budget for that either. (And 170 kWhs worth of battery pack in the belly pan...)

But back to the subject at hand, there seems to have been a similar thread to this one at some point:

http://www.diyelectriccar.com/forums/showthread.php?t=35352



NickRummy said:


> I seen someone wanting to convert a Sammy but I think he had an insanely low budget and was wanting some unrealistic numbers for performance.
> 
> I do like the idea about the fork lift scrapping. I was looking around in that thread about the motors and it could definitely be a possibility. I'm really curious about how heavy this thing will be. I'm also curious to see how well these motors will run using a low throttle input and a lot of resistance? (trying to drive over an obstacle)
> 
> ...


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## akseminole (Jan 5, 2014)

Another real world experience that I found:



Jeremyfc1 said:


> i run an electric samurai and have found that high gear in the trans is only good for road use and low range im in first or second the whole time i am off road i am running twin 6.7 chain driving the transmission all stock sami drivetrain i originally was going to just run the transfer case direct drive but found there was not enough ratio to truly crawl


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## dcb (Dec 5, 2009)

I would look closely at what this guy did.
http://www.evalbum.com/1149

maybe update the batteries, consider salvage EV lithium, learn about controller options (and kits), consider how to lower the voltage requirements of the motor, i.e. look for a 230v 15-20hp 4 pole (<~1800 rpm @ 60hz) motor with good efficiency and reasonably light (trade more amps for less volts, might get higher top speed with lower voltage pack). 

He didn't spend a whole lot, it is AC, it is a large motor that can make a lot of torque, " 337Nm on controller thus no gearbox required."

but I think Tuarn has really kind of spelled it all out for exactly doing A/C motor direct diving 4x4 tcase


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## evforme? (Jul 23, 2015)

Those old sami and tracker tcases don't have much reduction, I was thinking of using a toy gear driven case with a 2.66 reduction but it would be nice to shift on the fly.


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## dcb (Dec 5, 2009)

sorry, without some links or anything, I'm not sure what you are referring to.

tuarns car says:
1982 Suzuki Sierra SJ40 
Ratios motor to wheels through transfer case..
High 2wd 6.5:1
Low 4wd 10.5:1

this says:
http://www.suzuki-forums.com/suzuki-jimny-sierra-samurai-forum/35172-diff-ratios.html
SJ40 ran 4.1:1 ratios, SJ50 ran 3.9:1 and the SJ70 used 3.7:1.
years are this: SJ40 1981-1987; SJ50 1984-1989; SJ70 1989-1998

so it has a 4.1 diff, which means it has about a 1.6 high and a 2.6 low.

you have to consider the differential ratio as well though (and tire size). Try searching out possible cars and looking up their specs. 

I do like the driveshaft connection from motor to transfer case, that is a lot easier to get right than an adapter plate/transmission/etc.


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## evforme? (Jul 23, 2015)

Did some more digging and maths for those who may be interested.

A couple baselines.

Lets say a 5000rpm ceiling for the motor and a 33" tire.

A 4.88 diff at 1:1 tcase tops out at 162kph
Reduced at 2.66 = 61kph
At 2.3 = 70kph so a tcase ratio from 2-2.5 would work or lower with a higher diff reduction.

All easy cheap pieces to find, the trick is shifting from hi to low range on the fly, very few tcases have low range scyncros. Some examples may be from merc g wagons, land rover discos, and atlas brand but all potentially very expensive. An alternate aproch may be using the controller to rev match for syncroless shifting.


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## evforme? (Jul 23, 2015)

dcb said:


> sorry, without some links or anything, I'm not sure what you are referring to.
> 
> tuarns car says:
> 1982 Suzuki Sierra SJ40
> ...


Ya that sami is showing final drive ratios, its tcase should be somewhere around 1:1.6. unless your running a doubler or specially built one a tcase higher then the low 1:3 range would be rare.


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## dcb (Dec 5, 2009)

Do you mean you know of a 1.3 gear that could drop into a 1.6 tcase and retain the 2.6 low (like a 5th gear swap on a saturn or vw?)? 

how about a 6.5 low? and some tall tires 
http://www.rocky-road.com/samurai-transfer-case.html
(like $800 complete, or $500 for all the parts to convert your case).


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## evforme? (Jul 23, 2015)

dcb said:


> Do you mean you know of a 1.3 gear that could drop into a 1.6 tcase and retain the 2.6 low (like a 5th gear swap on a saturn or vw?)?
> 
> how about a 6.5 low? and some tall tires
> http://www.rocky-road.com/samurai-transfer-case.html
> (like $800 complete, or $500 for all the parts to convert your case).


Not sure what ya mean there, most tcase are 1:1 high then whatever low not talking about final drive, I don't know off the top of my head about swapping gears out but I think some Dana's and atlases can. it'd be cheaper to get that 6.5 low doubling up a couple used Dana's or Toyota cases with homemade adapters .

Read hat link, i think im getting my sami andctracker/sidekick stuff mixed up. Now you got me double guessing myslef, something in the back of my mind is remembering something about a tracker that had a reduced 2/4 hi.


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