# Project Planning - Suggestions please



## NickRummy (Aug 17, 2009)

After doing a lot of reading on other projects I wanted to state that I'm not really concerned about range. This will be an offroad vehicle. I'm trying to keep it as light weight as possible to help with power requirements and range. If I can get 5+ miles of play time I'll be happy, I would be interested in setups that could provide more range (which I know will vary according to terrain). Anything more than that would be a bonus. This is a play toy that will be trailered to play spots.


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## samborambo (Aug 27, 2008)

NickRummy said:


> After doing a lot of reading on other projects I wanted to state that I'm not really concerned about range. This will be an offroad vehicle. I'm trying to keep it as light weight as possible to help with power requirements and range. If I can get 5+ miles of play time I'll be happy, I would be interested in setups that could provide more range (which I know will vary according to terrain). Anything more than that would be a bonus. This is a play toy that will be trailered to play spots.


 
Buy a second hand golf cart.


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## Woodsmith (Jun 5, 2008)

Or have a look at this thread started by Jimdear2 about his tractor.

You don't say what sort of 'play' you want to do with it.


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## NickRummy (Aug 17, 2009)

samborambo said:


> Buy a second hand golf cart.


I should have been more specific. A golf cart is not what I'm after.



Woodsmith said:


> Or have a look at this thread started by Jimdear2 about his tractor.
> 
> You don't say what sort of 'play' you want to do with it.


Very cool thread! I'll have to give that a good read tonight. Just to keep it simple I basically want to convert a suzuki samurai however the only thing I'll be using from the Sammy is the drive train minus the transmission. Using only these parts gives me the gear ratios above. The chassis will be custom. It will be used for a trail riding and four wheeling mainly. Solid axles front and rear, 4-link suspension and shaft driven from the chassis mounted transfer case. I'm thinking the motor's output will go directly to the input on the transfer case. 

I should probably find out what kind of power the stock gas motor puts out and how much torque is applied to the transfer case after the transmission since I won't be using the transmission and need to at least replicate that torque number.


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## Woodsmith (Jun 5, 2008)

Someone else is suggesting the same vehicle for a similar use in the conversions and builds forum.

Have you thought about converting a 4x4 quad bike?

If you are fitting the motor straight to the transfer case then you will need to have an electrical reverse gear to use.

basically it sounds like you just need to install the complete motor, controller and battery pack from a fok lift and it will be pretty much done.

You are not looking for speed and you won't have the weight so it should move pretty well.

Buy a whole, scrap fork lift and charger and try it that way. You might even want to use the hydraulics for a bit of fun controlling the axle articulation and ride height.


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## NickRummy (Aug 17, 2009)

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)

The stock 1.3L in these trucks put out 66hp @ 6500rpm and 76ft-lbs and were mated to a 5spd tranny with the following ratios (I multiplied out the torque figures that would be going to the transfer case based on each gear)

1st - 3.652 (277.6ft-lb)
2nd - 1.947 (148ft-lb)
3rd - 1.423 (108.1ft-lb)
4th - 1.000 (76ft-lb)
5th - 0.795 (60.4ft-lb)

So in most cases you run offroad in 1st gear which means in the stock Sammy they're putting 278ft-lb to the input on the transfer case (which is divorced) so I guess I'd like to find a motor capable of putting out that torque number (or a bit higher of course)

Now if the motor spun up to 6500rpm then 1st gear that would drop that down to 1,780. 

So basically I am looking for a motor capable of about 1800rpm and 278ft-lb? Sound reasonable? 

Curb weight on a stock Sammy is about 2,100lbs and I'm looking to reduce that weight by a lot. A stock sammy wheels pretty well with the stock motor so if I can get that type of power I don't think I'll have any problems with what I want to do.


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## NickRummy (Aug 17, 2009)

So looking at specs on some of the more commonly used motors they are not putting out anywhere near 278ft-lb of torque. I think I can find a transfer case that has double the gear reduction which means I would then need a motor with around 3600rpm and 140ft-lb. The highest torque rating I could find was the warp 11 @ 135ft-lb. I wasn't looking to spend that kind of money on a motor  

Are the torque specs the same on all voltages assuming the power source can supply the current?


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## dimitri (May 16, 2008)

NickRummy said:


> So looking at specs on some of the more commonly used motors they are not putting out anywhere near 278ft-lb of torque. I think I can find a transfer case that has double the gear reduction which means I would then need a motor with around 3600rpm and 140ft-lb. The highest torque rating I could find was the warp 11 @ 135ft-lb. I wasn't looking to spend that kind of money on a motor
> 
> Are the torque specs the same on all voltages assuming the power source can supply the current?


So right there you came to realize why people don't convert EVs without transmissions  , congratulations on learning a lesson on your own, using proper math figures.

Now, you can find best motor you can afford and see how you can adapt the gear ratio to get desired torque and RPM. If the motor that fits the specs doesn't fit the budget, then adjust either budget or the specs until they meet 

Good luck!


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## NickRummy (Aug 17, 2009)

Thanks Dimitri, at least I know I'm moving forward in planning. I really wish I had a better idea of the weight this thing will be. 

The reason I'm trying to figure all this out ahead of time is so that I can get the drive train and get started on drawing things in CAD. If I have an idea of the drive train and power plant then I can design the chassis around those.

The only other gear reduction I can get will be through the differentials in the axles. I was planning on stock gearing but it looks like I can go from 3.73 to 5.12 and even up to 5.62 with some serious searching.


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